Manipulating map objects

Transcription

1 107 6 Manipulating map objects Understanding MapInfo: A Structured Guide Ian Jonson Arcaeology (P&H), University of Sydney

2 108 DRAWING NEW OBJECTS Te Drawing toolbar contains a number of standard drawing tools wic can be used bot for drawing objects wit te mouse and for digitising objects wit a digitising tablet (see capter 9). Objects are inserted into te current editable layer on a map window. Drawing tools operate bot on map windows and on layout windows. Te drawing tools are available wen a layout window is active or wen a map window wit an editable layer is active. If a map window wit no editable layer is active, te drawing tools will be greyed out.? Te tools available are: Symbol tool. Click on map to draw point objects in te current symbol style. Line tool. Draws individual straigt lines in te current line style. Press, drag and release to draw line in current line style. Sift to constrain at 0º, 45º, 90º. Ctrl extends line in opposite direction simultaneously. Polyline tool. Draws open polylines (lines composed of multiple straigt segments) in current line style. Click for individual nodes. Terminate line by double clicking. Sift constrains to 0º, 45º, 90º line segments. Polygon tool. Draws closed polygons in current region style. Click for individual nodes. Automatic closure if node is witin snap distance (page 125) of starting point, or close polygon by double clicking (mouse) or closure button (digitiser - pages 213, 217). Sift constrains to 0º, 45º, 90º line segments. Arc tool. Press and drag out to desired arc size and sape. Sift constrains to arc of circle. Ctrl centres arc on starting point. Circle/ellipse tool. Press and drag out to desired radius/sape. Sift constrains to circle. Normally centred on start point. Ctrl constrains tangential to start point. Rectangle tools (sarp and rounded corners). Press and drag out to desired size and sape. Sift constrains to square. Ctrl centres on starting point (reverse effect to circle/ellipse tool). AAA 6AAAAAAA Text tool. Click position to enter text - brings up text insertion bar and inserts text typed in current text style. Text can be several lines separated by Enter. Click elsewere, select anoter tool or press Escape to complete text. Double click text wit Select tool to edit text or modify style.

3 109 Drag and drop tool. Use tis tool to drag a map window onto te MapInfo desktop (to clone te map window) or into an OLE container application (page 115). Autoscrolling Wen you are drawing on a map or layout window wit a drawing tool and you move te pointer beyond te edge of te window, te map or layout will scroll in tat direction, allowing you to draw beyond te limits of te original window. You can stop scrolling by pressing Escape - te tool remains active.? Autoscrolling only operates wit tools wic can be dragged. Single click tools, suc as Info or Symbol, do not support autoscrolling. Adding tabular data Tabular data can be added to newly drawn objects on a map in one of two ways: Click on an object wit te Info tool and enter data into te Info tool window (page 152); Higligt (select) te object(s) using any of te normal selection metods (page 86) and open a new browser window for te Selection table. Enter data into te browser (page 153). Newly drawn objects can be automatically associated wit an existing record in te tabular data by first selecting te record in a browser ten drawing te object. New (blank) records can be added to te browser/table wit Edit>New Row (Ctrl-E).

4 110 MODIFYING EXISTING OBJECTS Te map object(s) to be modified must be in te editable layer. Te editable layer is indicated in te status bar at te bottom of te screen. 1 Select te object(s) by any appropriate metod (selection on te map - pages 86-88; selection on a browser - page 88; selection troug queries - pages 89-91). 'Handles' will appear at te corners of te bounding rectangle for lines, areas and text, one andle will appear at te centre of point symbols, and an additional andle (used for rotation) appears on text objects. If te andles don't appear, te layer is not editable or tere is a selectable layer above te editable one and objects ave been selected from tis instead (objects can only be selected from one layer at a time)? Undoing edits Te last editing action (delete, move, copy, resize etc.) on a map window (or browser) can be undone by Edit>Undo (Ctrl-Z). Undo is limited to te last action and to a limited number of objects/records (maximum 800, default 10, set under Options>Preferences>System Settings). Beware: If te number of objects/records modified exceeds te number set, NONE of te canges are undone.! Deletion To delete te selected object(s), press te Delete key or Edit>Clear. Tis deletes bot te map object and te tabular data If you delete te current selection in a browser, using Edit>Clear or te Delete key, te associated map objects are also deleted, because tey cannot exist witout tabular data. Objects and teir associated tabular data can be deleted to te clipboard wit Edit>Cut (Ctrl-X) - see detailed discussion on pages ! Edit>Clear Map Objects Only deletes only te selected map objects, but leaves te tabular data unaffected. 2 AAA 6AAAAAAA 1 Te status bar can be switced on and off wit Options>Hide/Sow Status bar. 2 You migt use tis prior to using Table>Create Points to ensure tat new map objects are created from te X,Y values in te tabular data (wic migt ave been modified), oterwise new map objects will not be created for tabular records for wic a map object already exists (page 64).

5 111 Duplication To duplicate te selected object(s), use Edit>Copy (Ctrl-C) ten Edit>Paste (Ctrl-V). Tis creates duplicate object(s) at te same location as te original(s). Point at one of tese objects, press and drag te duplicate(s) to te location required. Were multiple objects are copied and pasted, dragging any one of te pasted objects, as long as tey are still selected, will drag te rest of tem te same amount (see "Moving" below). Cutting, copying and pasting are discussed on page Moving Note: Tere is a one second delay after te mouse button is pressed before te object(s) can be dragged. Tis delay exists to avoid inadvertent moving of objects wen te mouse is clicked to select an object and moved at te same time. Single object To move a selected object, point at any part of te object wit te Select tool, press, drag and release. If te object is a polyline or text, te pointer must be on part of te line or on a caracter, oterwise te object will be deselected instead. Te window will autoscroll (page 109) if te pointer moves off te edge of te window. Multiple objects Wen multiple objects are selected (page 86), point at any one of te objects and drag it. All objects are moved by te same amount. Tis is true weter or not all te selected objects are visible on te screen. Tis is particularly useful for labelling e.g. large numbers of point objects, grid lines or map outlines. Having autolabelled te objects using te tabular data (e.g. wit site name or identifier, grid latitude, map number etc.), one can zoom in on a small area for precise positioning of lettering relative to te objects and know tat all te oter labels selected will ave been moved by te same amount.! Beware: moving a line or area object outside te defined coordinate limits of a non-eart projection will cause te part moved outside te defined limits to be truncated unpredictably. Moving a line or area object back into te mapped area will not reinstate te truncated section.? Point objects moved outside te coordinate limits will 'stick' at te edges of te defined area (tey will appear to move past te edges, but once te mouse is released tey will jump back to te nearest edge).? Text objects beave in a rater more complicated manner: teir centroid 'sticks' at te edge of te defined area, but te actual text can extend beyond te limits in some circumstances. If moved off te bottom or top tey are rescaled. If moved back into te defined area, any truncated text is reinstated, but te scaling remains.

6 112 Rescaling To rescale (enlarge, reduce or cange te overall sape of) selected line and area objects, use te Select tool to drag te andles at te corners. Wen multiple objects are selected, dragging te andle on any of te objects will rescale all te objects and te space between tem. Te andle can be dragged more in one direction tan te oter to cange te sape of te objects (e.g. squares into rectangles). Hold down Sift to rescale in proportion (i.e. to maintain te same overall sape). Hold down Ctrl to rescale around te centroid (normal rescaling expands or contracts te object(s) in te direction of te andle wic is dragged). Sift and Ctrl can be eld down togeter to get proportional scaling around te centroid. Point objects (symbols) and text objects cannot be rescaled - teir size is modified using te style settings (page 117). However te space between tem can be scaled if te selection includes a line or area object wose andles can be dragged. Autotracing Wen drawing or digitising 3 contiguous polygons (suc as a soil map or cadastral plan) te boundary between two polygons must be duplicated. If it is traced twice (once for eac polygon) tere will be overlaps and/or gaps between te two boundaries (page 218). Tis is bot messy and can result in errors suc as te attribution of a point to two polygons or to no polygon at all if it falls in an overlap or a gap respectively. MapInfo's Autotrace function is one way of avoiding manual retracing of boundaries and ensuring tat duplicated boundaries are identical. To use Autotrace, you must be in snap mode (page 125) - turn on/off by pressing S. Draw or digitise as normal until you reac te first node of te section of boundary wic you wis to trace. Switc on snap mode if it isn't already on. Click to place a node in your new object coincident wit te starting point of te section to be traced, ten old down te Sift key and point to te last node in te section to be traced. Te straigt line between te last node and te pointer will disappear and te pat between te two, along te object, will be marked. Click on te last node wile continuing to old down Sift to include te marked section in your new object. Continue drawing or digitising until te new object is complete. You can include more tan one traced section in an object. Te first and last nodes in te section to be traced must be part of te same object, oterwise te autotrace function as no effect and a straigt line is drawn between te nodes. However Autotrace will trace objects in any layer, not just te one you are editing.? Normally MapInfo traces te sortest pat along te object between te two nodes. If you old down Ctrl rater tan Sift wen tracing a polygon, MapInfo will trace te longer pat. AAA 6AAAAAAA 3 Digitising (capter 9) is precisely equivalent to drawing wit a mouse, except tat te position of te digitiser puck is converted to coordinates relating to te paper map or aerial potograp (and tereby to te real world), rater tan to te arbitrary space of te computer screen.

7 113 CUTTING AND PASTING Bot tabular data and map data can be copied, cut and pasted wit te usual Windows commands (Ctrl-C, Ctrl-X and Ctrl-V), eiter witin MapInfo or between MapInfo and oter applications. Cut and paste witin MapInfo Witin MapInfo, map objects are cut and pasted as map objects to te same geograpic location in watever layer is currently editable (not necessarily te same layer as te one from wic te objects were cut or copied). Map objects are pasted as new objects and will not replace a igligted selection. Wen a map object is cut and pasted into a map window, te associated tabular data is also pasted into te tabular data for te editable layer, creating new records. If data is cut from a browser and pasted into a map window, bot te map object and tabular data are pasted.! Wen rows are cut from a browser, te corresponding map objects are cut from te table, even toug te layer may not be editable on any open map window.! If data is pasted into a browser, te map objects are not pasted into te table.! Wen tabular data is pasted into a different table and te table structures are different, te results are unpredictable (MapInfo matces fields by order and type, so fields may not be pasted if te fields in te recipient table do not matc up). No tabular data is pasted wen map objects are pasted to te cosmetic layer.? Since cut and paste always transfer tabular data (oter tan wen pasting map objects to te cosmetic layer), it is not possible to paste into a read-only table (suc as a table based on a spreadseet or ASCII delimited file, or one locked by anoter application). Wen a group of nodes are selected (by selecting tem in resape mode - page 123) and ten cut or copied, tey will be pasted as a polyline. Wen a single node is pasted, it will be pasted as a point object. Copy and paste map window Wen a map window is active and no objects are selected, Edit>Copy is modified to read Edit>Copy Map Window. Wen a map window as been copied to te clipboard, Edit>Paste is modified to Edit>Paste Map Window. Pasting a map window creates a new map window, equivalent to Map>Clone View or dragging te map window onto te MapInfo desktop wit te drag and drop tool. One use for tis is to create a second view of te same data wic can be zoomed in to create a pull-out from a small area.

8 114 Moving objects witin/between layers Were several objects in te editable layer lie on top of one anoter, cut and paste will generally move te selected object(s) to te front (as will any editing action suc as resaping or canging style). Cut and paste can also be used to move data from one layer to anoter. Cut from one layer (wic must be editable), make anoter layer editable, and paste te cut objects back into tis second layer. Tabular data is moved wit te map object(s). Alternatively, cut te objects from a browser (te map objects are cut as well, weter or not te map layer is editable) and paste tem back into te editable layer on te map window. Pasting text to a map window Pasting text (e.g. text cut from a wordprocessor, as distinct from a text map object) into a map window will paste te text as a text object in te current text style at te centre of te map window (it can of course ten be moved elsewere). It will not overwrite a igligted text object on te map or paste to an insertion point placed wit te text tool.? Cutting or copying text from a map window places a text map object in te clipboard wic will be pasted back into its original geograpic position in its original text style. Cut and paste witin dialogue boxes As wit all Windows programs, text can be cut and pasted between fields in dialogue boxes using Ctrl-X, Ctrl-C and Ctrl-V. Higligted text will be replaced by pasted text or insertion will occur at te current cursor position. Cut and paste to oter programs Te beaviour of cut and paste to oter Windows programs is determined by te options set under Copy to Clipboard wic is reaced troug Options>Preferences>System Settings: Enable Copy TEXT to Clipboard to copy tabular data, Copy BITMAP to Clipboard to copy map data as a single bitmap representation and Copy Metafile to Clipboard to copy map data as individual (vector) objects. All tree types of copy can be enabled simultaneously.? In grapical applications, suc as a drawing package, Edit>Paste will paste te bitmap by default. In text applications, suc as a wordprocessor, Edit>Paste will paste te tabular data by default. To paste te bitmap or metafile, use Edit>Paste Special and coose Bitmap or Picture respectively. AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA Wen pasting into a text application, suc as a wordprocessor, te fields are pasted wit tab 6AAAAAAA AAAAAAA AAAAAAA caracters between tem and Return at te end of eac record. Wen pasting into a AAAAAAA AAAAAAA spreadseet, fields sould end up neatly in columns. AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA

9 115 OBJECT LINKING AND EMBEDDING MapInfo map windows can be dragged or pasted into OLE version 2 container applications suc as Microsoft Word 6, creating an embedded OLE object 'MapInfo Map'. Tis object can be manipulated using a subset of MapInfo commands by double-clicking on te object in te container application (te object border and te menu and tool bars cange appropriately):? Object linking and embedding is only available in 32 bit MapInfo (Win 95 or Win NT). For 16 bit MapInfo, te map window is pasted as a bitmap. Drag and drop To drag a map window to an OLE container application, select te drag and drop tool, click anywere on te map window, drag and drop onto te destination application window. A no-go icon will sow in areas were te map object cannot be pasted. Map windows can also be dragged and dropped onto te MapInfo desktop, in wic case a clone of te map window is created wit full MapInfo functionality. Copy and paste To copy and paste a map window into an OLE container application, make te map window active and remove any selection using Query>Unselect All. Copy te map window to te clipboard wit Edit>Copy Map Window (Ctrl-C) 4 and paste into te container application wit Edit>Paste Special. Edit>Paste Special allows you to select display of an icon labelled 'MapInfo Map' witin te destination application, as an alternative to te map window itself. Tis makes it quicker to move around in te destination document, as you don't ave to wait for te map(s) to redraw. For more information on object linking and embedding, see MapInfo Reference pages Edit>Copy Map Window is only available if no objects are selected on te map window.

10 116 MAP OBJECT STYLES Te style of symbols (point objects), lines (line objects), regions (area objects) and text (text objects) can be canged wit te style entries on te Options menu or teir toolbox and keyboard equivalents: Object type Toolbox icon Keyboard sortcut Options menu entry Point/symbol Alt F8 Options>Symbol Style Line/polyline Sift F8 Options>Line Style Area/region Ctrl F8 Options>Region Style Text F8 Options>Text Style Selecting te menu entry or toolbox icon will display te appropriate style dialogue. Clicking on te pull-down lists will display te alternative symbols, line and fill styles, colours etc. available. Scope of application of styles Canges made in te style dialogue box apply: To select objects on te currently active map window: te map layer must be editable; To any objects of te same type (point, line, area or text) wic are drawn until anoter style cange is made. You can also modify te style of an object, and all subsequent objects drawn, by clicking te style button on te object information dialogue (see below). MapInfo's beaviour in canging bot te style of selected objects and te default style for tat type of object, is contrary to normal Windows conventions (were te default style is canged only if no objects are selected and can be extremely frustrating). It is to be oped tat tis 'feature' will be fixed in a future version.? Wy styles don't cange AAA 6AAAAAAA Te style of selected map objects will only cange if tey are in te editable layer. Ceck tat te objects wose style you are trying to cange sow editing andles. If te objects are in te editable layer, ceck for style override (page 82). If style override is on for te layer containing te objects, te objects will display wit te styles specified under style override, watever te individual styles applied to te objects. Your style canges will ave been made, but tey will only sow wen style override is turned off.??

11 117 Point object style Te Font list allows selection of any of te Windows fonts installed, including special MapInfo fonts. Te default is MapInfo Version 3 compatible symbols, wic is not a True Type font. N in te font pull-down indicates a null symbol, i.e. no symbol will plot. Maximum symbol size is 48 point. Minimum size in te pulldown list is 9 points, but smaller sizes can be typed in and are generally useful down to about 4 point. Rotation, Background and Effects are only available for True Type fonts. Rotation gives te angle of rotation in an anticlockwise direction. Te different backgrounds (None; Halo; and Border) are exclusive - only one at a time can be selected - wereas te effects (Drop Sadow and Bold) can be applied togeter. New symbols can be defined troug te Symbols MapBasic application, supplied wit MapInfo, or created as bitmaps in te CustSymb directory (see page 246 for details). Line object style Line styles are limited to tose provided by MapInfo. Tere are a number of conventional cartograpic line styles towards te end of te pull-down list of styles (sown on rigt, above), but te paucity of styles and te inability to create new ones is a problem for cartograpic applications. N at te start of te list indicates a null line style, i.e. no line is drawn. Null lines are particularly relevant for line styles associated wit area object (region) boundaries (see below) wic may not require borders. Note te line styles wit a symbol at eac end (arrows or blobs). Tese can be useful for drawing in arrows or empasising te ends of lines, but te quality of te arrows is poor and

12 118 tere is no coice of arrow style. A utility for creating arrows in different styles is available from te GISNet MapInfo FTP site (Appendix I). Region object style Uncecking te box to te left of Background in te Region Style dialogue makes te fill background transparent, so tat underlying objects can be seen troug it. Te pattern sown in te Patterns list is drawn in te Foreground colour; te spaces between te atces, dots etc. are te background. Note tat N in te line style or fill pattern lists means no line or no fill respectively. No fill is transparent, so tat polygons, rectangles etc. wit tis fill style do not obscure underlying objects (even an apparently empty fill will obscure underlying objects, because it is a solid fill in te colour wite). Text object style Text style applies to te wole of eac text object - te style cannot be canged for an 6 individual word or oter sub-string. Individual text objects can be rotated, justified and spaced

13 using te Text Object dialogue (see below): tese are not available as part of te text style dialogue (page 120), wic is limited to setting te font styles. 119 Text sizes Text font size is a rater complex issue, because font sizes beave differently for text objects on a map window, labels on a map window and text on a layout. Text map objects On a map window, point size as no intrinsic meaning. Text maintains a constant geograpic size and text point size is measured relative to te screen. 5 As you zoom in or out, text objects will become larger or smaller, and te point size (as sown in te text style dialogue) canges accordingly.! If you click OK in te text style dialogue, te default style for future text objects will be set to te point size and font indicated. New text objects are drawn at tis default point size relative to te current screen, so tey will be geograpically large if drawn on a zoomed-out map, small if drawn on a zoomed-in map. Te style of text objects on layouts is also reset. Object labels Text labels on a map window (i.e. labels created wit te labelling function or label tool) maintain a constant size relative to te map window, watever te zoom. If te text style dialogue is opened wit labels selected, it will sow te same point size watever te map scale. Labels become larger in proportion to oter map objects, and te space between tem, as te map is zoomed out, smaller as it is zoomed in. Point size, and oter aspects of text style, set ere do not affect future text objects on maps and layouts. Layout text On a layout window, text point size is te actual point size at wic te text will print. Altoug te text gets larger or smaller as you zoom in or out, its point size stays te same. Point size, and oter aspects of text style, set ere does affect future text objects on maps and layouts. Standardising text object size If you ave drawn or canged text objects on a map in more tan one batc, your text will probably be all different sizes. To fix tis, select all te text objects, zoom in until you can see some of tem at a readable size and use Options>Text Style to set te font to te point size you want at tat zoom. All te selected text objects will be reset to te same size, even toug tey are not visible on te screen. Zoom out to ceck tat it looks rigt on te wole map. For more information on text objects, see "Modifying text objects" on te following page. 5 Point size relates to nominal screen size. Nominal screen size does not relate to monitor size but to video driver resolution. A 640x480 driver generally defines te screen as 5" ig at a resolution of 96 pixels per inc. A 1024x768 driver generally defines it as 8" ig, at te same resolution.

14 120 MODIFYING INDIVIDUAL OBJECTS To modify te position, sape and style of a map object, use te Select tool to doubleclick on te object, or select it and coose Edit>Get Info (F7). A dialogue box is displayed giving information about te position, extent, style and smooting of te object (te exact dialogue will depend on te type of object - see te next section for Text objects): If te layer is editable, tis dialogue can be used to modify te position of te object, its style and, if applicable, te size, aspect ratio, smooting, font, justification and text orientation. If te layer is not editable, tese caracteristics are displayed but cannot be modified. Clicking on te Style button brings up te style dialogue box appropriate to te type of object, as described in te previous pages. Note: new colours can be defined using Options>Custom Colors (page 247). Custom colours are also available by clicking te ellipsis (...) at te end of te colours pulldown lists in eac of te style dialogues. AAA 6AAAAAAA

15 121 Modifying text objects Text entered wit te text tool appears in te current text style. To edit text after it as been typed, or to cange its style, double click on it wit te Select tool, wic will bring up te text object dialogue: Font, caracter size, style (bold, italics etc.) and special effects suc as aloing can be canged by clicking on te Style button at te top rigt, wic brings up te Text Style dialogue (page 118). Note tat canges to te text style affect future text objects as well as te current object. Te text can be rotated anti-clockwise by te amount given under Rotation Angle. Te text can also be rotated by dragging te andle just below and to te rigt of te text (labelled 1 below) wen it is igligted on te map window: 2 1 If eiter of te label line options (Simple line or Arrow line) is activated, MapInfo will draw a line wen te text is dragged away from its original position. Tis line connects te text wit te centroid of its original position. Te end of tis line as a andle (labelled 2 above) wic can be dragged back so tat it points at te desired location.

16 122 RESHAPING OBJECTS CHANGING SIZE AND PROPORTIONS Wenever a line or area object is selected in te editable layer, its overall sape (aspect ratio) can be canged by dragging te edit andles (page 85). Hold down te Sift key wile dragging te andles to rescale te object in proportion (i.e. witout canging its overall sape) or te Ctrl key to rescale around te centre of te enclosing rectangle. Sift and Ctrl can be eld down togeter. NODE EDITING For simple lines, arcs, polylines and polygons, te sape may also be canged by moving nodes, as follows: Select te object to be modified; To enter resape mode, coose Edit>Resape (Ctrl-R) or click te icon; Wen resape mode is active, te Resape tool icon will sow as pused in and andles will appear on eac node of te selected object: Wen two nodes coincide exactly on te screen tey do not sow, because te second node cancels out display of te first (page 85). Simple lines and arcs only ave two nodes, one at eac end, wic may be dragged to resape tem. Additional nodes can be added to simple lines, but not to arcs, wit te node addition tool (see below). To resape arcs, ellipses or rectangles by node editing, first convert to a polyline or polygon using Objects>Convert to Polylines or Objects>Convert to Regions.? AAA 6AAAAAAA

17 123 Selecting nodes In resape mode, te Select tool allows selection of individual nodes rater tan te object as a wole (clicking on anoter object selects te object and retains resape mode). Clicking on a node selects it. Te currently selected node is sown by a ollow andle (small square). Clicking on additional nodes wile olding down Sift selects multiple nodes. If te node clicked is not te next node along from te currently selected node(s), all intermediate nodes will also be selected. For polygons, Sift-click selects all intermediate nodes in te sorter pat between te nodes. Ctrl-click selects all intermediate nodes in te longer pat between te nodes. Ctrl-click on an already selected node selects all nodes in te object. Deleting and copying nodes Te current set of selected nodes can be deleted wit te Delete key or Edit>Clear, and deleted or copied to te clipboard wit Edit>Cut (Ctrl-X) or Edit>Copy (Ctrl-C). Multiple nodes deleted or copied to te clipboard are pasted back as a polyline. Moving nodes Te currently selected node(s) can be moved by dragging wit te Select tool wile in resape mode. If multiple nodes are selected, drag one of tem and te rest will move by te same amount. Note: Tere is a one second delay after te mouse button is pressed before te node(s) can be dragged. Tis delay exists to avoid inadvertent resaping of objects wen te mouse is clicked to select a node and moved at te same time. If you ave coincident nodes in two objects (for example, two rivers wic were snapped to join at a node, or a sared boundary between two polygons drawn wit autotrace), moving nodes in one object can (optionally) move te corresponding node in te oter object. Tis beaviour is enabled troug Options>Preferences>Map Window (page 244).? MapInfo will not searc troug all layers for duplicate nodes - te objects must be in te same map layer. To ensure tat coincident nodes are moved togeter, tey sould be drawn or positioned using snap mode (page 125). Moving centroids If object centroids are sown for closed objects (enable using Map>Layer Control>Display and ceck Sow Centroids) tey can also be moved (but only witin te outline of te object). Tis may be useful as a means of controlling te position of automatic object labelling or te position of bar carts, pie carts or graduated symbols on tematic maps (labels and tematic objects are all placed relative to te object centroid). Note tat moving te centroid does not move existing labels. Moving te centroid may affect marquee select, radius select, boundary select and spatial joins (polygon witin anoter object) wic are all based on te position of te centroid.

18 124 Adding new nodes Add new nodes to a line, polyline or polygon by activating te Node addition tool and clicking anywere on te outline of te object to create a new node at tat point. Te node can be dragged to a new position, if required, before releasing te mouse button. Simple lines are converted to polylines by te addition of nodes. Nodes can only be added to arcs, ellipses and rectangles by first converting tem to a polyline or polygon (page 127). Te node addition tool can only be activated wen in resape mode.? Smooting Use Objects>Smoot to convert a jagged outline (defined by te nodes recorded - left and diagram) into a smoot curve (rigt and diagram). Smooting can only be applied to polyline objects. Select Objects>Unsmoot to switc off smooting.? Unsmooted Smooted Note tat objects are only smooted for display - if you export te data te original X,Y coordinates of te nodes on te line are exported. Te example above sows te position of te nodes - tey are te same for bot te smooted and unsmooted versions.! Curves can be smooted by te creation of additional nodes using a program in Curve.Zip on te GISNet MapInfo FTP site (Appendix I). AAA 6AAAAAAA

19 125 NODE SNAP It is often desirable for objects to meet up cleanly - for example, tributaries will join rivers witout a break, power lines sould run from pylon to pylon, and triangulation lines sould run precisely from te triangulation points to te target feature. If two objects are digitised separately, tey may appear to meet precisely, but zooming in will invariably sow a misalignment. To avoid tis problem, and to speed drawing and resaping of features wic sould join up, MapInfo provides node snapping. Snap mode is enabled by pressing S wen a map window is active (weter or not tere is an editable layer). Te status bar at te bottom of te screen will sow SNAP.? Wen in snap mode, crossairs will appear on te nearest node wenever te mouse or digitiser pointer comes witin te snap distance (see next page) of a node. 6 Te nodes to wic te crossairs snap can be in any layer: Mouse pointer indicates current mouse position Crossairs indicate node to wic current object will snap If te current tool is a drawing tool, any node created wen te crossairs sow will be created at te position of te crossairs, i.e. coincident wit te nearest node, rater tan at te actual position of te mouse or digitising pointer. Snapping also occurs wit oter tools allowing, for example, quick selection of nodes wit te select tool, dragging of nodes to snap wit oter nodes, zooming on a specific node, radius select from a node or accurate measurements of te distance between two or more nodes.? Altoug te crossairs will snap to nodes in any layer, only nodes in te editable layer can be moved or deleted, and any nodes or objects created will be in te editable layer. Wen selecting an object in snap mode, te displacement arrows ( ) will snap to a node in te selected object if one falls witin te snap distance. Wile te object is being dragged, te displacement arrows will continue to snap to nodes (in oter objects) wic fall witin te snap distance, so te object can be positioned precisely wit te node you selected coinciding wit a node in anoter object. Wen in snap mode, MapInfo is continuously searcing for nodes to snap to as you move te pointer. Wit complex maps or a slow macine tis can slow selection and editing on te map to a crawl. It is a good idea to turn snap mode on and off wit S as required. 6 For clarity, snap distance as been set to an unusually large value in te illustration.

20 126 Controlling snaps If you ave trouble wit tings snapping inadvertently, use Options>Preferences>Map Window to cange te snap tolerance:? Te default snap tolerance, i.e. te distance witin wic te pointer will snap to a node, is 5 pixels - a larger value can be entered if dealing wit sparse maps or a ig resolution screen. Enabling Move Duplicate Nodes in te Same Layer causes snapped nodes in te same map layer to be moved togeter, i.e. wen a node is dragged wit te resape tool (pages ) any node wic was snapped to it, or to wic it was snapped, will be moved accordingly: Only nodes in te same layer as te node being moved will be moved wit it, as only one layer can be editable at a time. Fortunately objects wic need to join up accurately are often, toug not always, in te same map layer (e.g. roads or rivers joining at a node or contiguous polygons wic must sare exactly te same boundary).? AAA 6AAAAAAA

21 127 POLYGON/POLYLINE CONVERSION Different types of line and area object can be converted to polylines or polygons. Polylines and polygons can also be converted from one form to te oter. Te main reasons for doing tis are: 1. to close open objects (by converting arcs and polylines to polygons) Closed objects suc as polygons can be filled and used in operations suc as witin-area selection of objects or area calculations. However, polygon outlines cannot be smooted. 2. to open closed objects (by converting ellipses, rectangles and polygons to polylines) Polylines can be duplicated were boundaries are sared. Polylines can be combined wit oter polylines were features ave been digitised in sections. Te outlines of polylines can also be smooted for display (page 124). 3. to create individually manipulable nodes along te object (by converting arcs, rectangles or ellipses to polylines or polygons). Tis allows te addition of nodes and selective deformation of te object. Rectangles convert to four corner nodes, as do rounded corner rectangles (te rounded corners are lost). Arcs and ellipses convert to multiple nodes (101 nodes per 360, proportionally fewer for arcs). Conversion is carried out as follows (te layer containing te object(s) must be editable): Select te object(s) to be converted; Use Edit>Convert to Regions to convert polylines, arcs, rectangles and ellipses to polygons (regions); Use Edit>Convert to Polylines to convert polygons, arcs, rectangles and ellipses to polylines. Te conversion assigns te current line style (Convert to Polylines) or region style (Convert to Regions) to te objects converted. Multiple polygon regions are converted to multi-section polylines not multiple polylines (i.e. tey remain as one object). Point and text objects are not affected by tese conversions. OVERLAYING NODES Objects>Overlay Nodes creates new nodes werever two line objects or te boundaries of two area objects intersect. Te nodes are created on te target object(s) - see next page - werever tey are intersected by te Current Selection. Overlaying nodes is useful for creating nodes at intersections of networks suc as roads or rivers. You can use te same objects as bot te target and te current selection - tis will create nodes werever te object(s) cross over temselves.? Wen nodes are displayed (in resape mode), nodes created by te intersection of an object wit itself do not sow, because tey occur in pairs - te second node cancels out display of te first (page 85).

22 128 COMBINING AND SPLITTING OBJECTS MapInfo as a number of commands in te Objects menu (Combine, Split, Erase and Erase Outside) wic allow one to: combine two or more objects togeter into a single object (and aggregate any tabular data for te combined objects); split or erase part of one or several objects using anoter object as a mask or 'cookie cutter' (and disaggregate te tabular data proportionally). Te mask must be an area object (polygon, ellipse or rectangle). Tese commands apply to line and area objects only. Tey cannot be used on point or text objects.? Setting te target A target can consist of one or more map objects wic must be in te editable layer. Te target is te set of objects to wic te action will be applied: modification wit split, erase and erase outside; addition of objects wit combine; creation of new nodes wit overlay nodes. Only a single object can be selected as te target for combine, wereas te oter actions can be applied to multiple target objects. To set te target, select map objects using any of te normal metods and coose Objects>Set Target (Ctrl-T). Te target object(s) will be igligted wit a distinctive pattern (set in Options>Preferences>Map Window). Setting a target is optional for combining objects, but is required for split, erase, erase outside and overlay nodes. Objects>Clear Target reverses setting of te target object(s) - it does not delete tem or affect tem in any oter way. Te target is cleared automatically after split and erase operations. Combine objects Objects>Combine turns te currently selected objects into a single object or combines te currently selected objects wit a target object. If no target as been set, te selected objects are combined into and replaced by a single composite object. Consequently te selected objects must be in te editable layer. If a target as been set, te selected objects are added to te target object, wic must be in te editable layer. If te selected objects are also in te editable layer tey are erased, oterwise tey remain uncanged. AAA 6AAAAAAA You can only combine line objects wit line objects (line, polyline, arc) and area objects wit area objects (polygon, ellipse, rectangle). Point and text objects cannot be combined wit oneanoter or wit anyting else.?

23 ? MapInfo gives te message 'You cannot combine linear and closed objects' if you select objects of mixed types (line and area togeter), but also, rater confusingly, if you select point objects or text objects. Te end product of combining area objects (polygon, ellipse, rectangle) will be anoter area object. If te original objects were not contiguous, te end product will be an object made up of several non-contiguous parts. If two or more contiguous or overlapping objects are combined, MapInfo will eliminate te boundaries between tem to form a single polygon.? Objects>Combine will be greyed out unless two or more objects are selected from te editable layer, or a target is set in te editable layer and at least one oter object is selected. Te tabular data from objects wic ave been combined is aggregated to create te tabular data for te resultant object. See "Aggregation and disaggregation of tabular data" (page 132). Wen combining objects wit a target, No Data leaves te tabular data for te target intact. Objects can also be combined using Table>Combine Objects using Column (page 131). 129 Split and erase objects Split and erase allow one to split objects into a number of separate sections or erase parts of an object using oter object(s) as a mask or 'cookie cutter'. To use te split and erase functions you must: 1. set te object(s) you wis to split or erase as target object(s) wit Objects>Set Target (Ctrl-T); 2. select te mask object(s) using normal selection metods. Te mask objects act as a 'cookie cutter' to split or erase parts of te target. Te mask objects must be area objects - you cannot erase or split wit a line object; 3. apply te required function (Objects>Split, Objects>Erase, Objects>Erase Outside). Objects>Split creates new objects for any areas in te target objects covered by te mask objects, and deletes tat part of te original objects. Were one mask object covers two or more separate sections of a target object, one new object is created comprising two or more polygons, as illustrated below:

24 130 In te example above, an inverted U (te target) as been split wit two rectangles producing tree objects (numbered 1-3). Note tat te parts of te original object wic were not covered by mask objects remain as one non-contiguous object, as do te separate parts of te new objects created by eac mask object. Objects>Erase erases any part of te target objects covered by a mask object. Objects>Erase Outside erases any part of te target object not covered by a mask object. Eac target object remains as one object even if te remaining sections are separated. Te tabular data attaced to objects wic ave been split or erased can be disaggregated to provide tabular data for te resultant object(s). See "Aggregation and disaggregation of tabular data" (page 132). Coping wit 'islands' Erasing is particularly useful for cleaning up digitised polygon data were polygons occur as 'oles' in oter polygons (for example, islands in a lake or 'islands' of one soil or vegetation type witin a large area of anoter). Tese are best andled by digitising te broad area first, ten te islands. Altoug tis would display correctly, a spatial operation suc as point-witin-polygon would assign, say, a sampling location on one of te islands to two landform/soil/vegetation categories, wic is clearly incorrect. Te same problem occurs wit elevation bands, if contours are digitised as closed polygons working upwards, or for concentric buffers around a set of objects (e.g. distance bands away from rivers, roads or te coastline). To clean up te data, select te broad area as te target, ten select all te islands and use Objects>Erase. 'Holes' will be made in te target into wic te islands fit. You may need to old down Ctrl wile clicking to select islands wic ave disappeared beind a larger area. Cutting and pasting an island will bring it to te front, as will canges to its display style (e.g. border colour or fill pattern). Creating a study-area dataset Erasing wit a mask can also be used to select data for a study area out of a larger dataset. Wile one can use normal selection tecniques (capter 5) to select objects witin te study area and ten save tem as a new table, te trailing bits of tese objects wic extend outside te study area will also be saved. Objects>Erase Outside can be used to erase everyting outside te study area, or Objects>Erase can be used around te edge to trim off te excess. If you are creating te study area only for display purposes and not for analysis, you may prefer to define clipping of te map (page 99) to sow only te area in question, witout modification to te underlying data. AAA 6AAAAAAA

25 131 COMBINING OBJECTS USING TABULAR DATA Selecting and combining objects on a map is particularly useful as way of cleaning up map data. For example, you migt use it to combine two alves of a feature digitised off two separate map seets, combine soil classes to create a coarser classification, combine administrative districts wic ave coalesced or combine a cain of islands into one multi-polygon object for analytical purposes. It is suitable were tere are just a few objects to combine, or objects occur in clumps wic can be easily selected in one operation. Selecting and combining objects on a map is not so suitable were you wis to combine large numbers of objects scattered across te map, or were tere are many different groups of objects you want to combine. You migt, for example, want to combine dozens of small patces of soil classification into a single multi-polygon object representing sallow stony soils, ten repeat for oter scattered patces to create a series of broader soil classifications. Quite often, te information required to combine objects is stored in te tabular data. For example, a coarse soils classification as well as a detailed classification may be stored for eac patc of soil; eac National Park, nature reserve or exploration licence may record te administrative region to wic it belongs; sampling units may record topograpic and environmental information wic migt be used to group units. Table>Combine Objects using Column allows map objects wic sare te same value in a particular column, to be combined automatically. It can create a wole series of new objects in one go, rater tan producing just one new object eac time you use Objects>Combine. Te menu entry will be greyed out unless you ave at least one writable table open. As wit Objects>Combine, te new object can replace te objects wic ave been combined, or te new object can be created in a different table, leaving te original objects unaffected. To replace te existing objects, specify te same table under Combine objects from table and Store results in table. To create new objects witout affecting existing objects, specify a different table under Store results in table. Te table specified as te destination of te objects must be writable (but need not be editable on any map window). Group objects by column specifies te column (field) olding te values wic are sared between multiple records. Te field will normally be some sort of coded or standardised name field, or small integer numerical values. As wit Objects>Combine, te tabular data from te objects combined is aggregated to create tabular data for te new objects. See "Aggregation and disaggregation of tabular data" (page 132).

26 132 AGGREGATION AND DISAGGREGATION OF TABULAR DATA Wen map objects are combined, split or erased, te attaced tabular data for eac of te objects must be combined (aggregated) or split (disaggregated) in some way to create tabular data for te resulting object(s). Aggregation For Objects>Combine and Table>Combine Objects using Column, you will get te following data aggregation dialogue: Different metods of aggregation will be appropriate for different fields. For example, if combining sample quadrats witin a particular site, one migt want to enter a Blank for te quadrat ID (since eac quadrat would ave a different ID), record te (sared) Value of te site ID, Sum te number of plants or artefacts recorded in all te quadrats, and Average te density for te quadrats, peraps Weigted by quadrat area. Multiple fields can be selected wit Sift-click and Ctrl-click selection, and teir aggregation metods can ten be canged all togeter by selection from te Aggregation Metod options. If you are aggregating witin a single layer (i.e. te target object, if set, and te selected objects are all in te same table), Aggregation Metod will sow a pulldown list of fields for Weigt by. If you are aggregating objects from one table to insert into anoter table (te target object is in a different layer from te selected objects, or you are combining objects from one table and storing te resultant objects in anoter), Aggregation Metod will sow a pulldown list of fields next to Value. If a target is set, Value will sow te value of te selected field for te target object, wic may be modified if required. AAA 6AAAAAAA Before you can select sum or average you must select te source field in te pulldown list next to Value under Aggregation Metod - until te source field is selected, sum and average are greyed out. Tey will also remain greyed out if te source field is not a numeric field. Default aggregation metod is sum for numeric fields and value for non-numeric fields.?

27 ? Sum and average will also remain greyed out if multiple destination fields are selected and any of te selected fields are non-numeric. No cange is only available if tere is a target. Blank is only available if tere is no target. Cecking te No Data box is a sort cut, in cases were one is not interested in any of te tabular data for te selected objects. If tere are target object(s), te data for te target object(s) will be retained intact. Aggregation is 'remembered' from one operation to te next, so it is not necessary to reenter te aggregation specifications eac time objects are combined. 133 Disaggregation For Objects>Erase, Objects>Erase Outside and Objects>Split, you will get te Data Disaggregation dialogue. Te coices for disaggregation are similar to tose for aggregation: Use Blank were te tabular data field is of no interest or ceck te No Data box if none of te tabular data is of interest. Use Value were all te objects created will ave te same value (as in te name or ID of an area being split, or some classification of its content), and Area Proportion were te field represents some quantity or property of te area wic can be assumed to be uniformly distributed and apportioned in proportion to te area of eac of te resulting objects, suc as counts of incidents or objects, total income, value or yield. SAVING CHANGES Use File>Save Table to save canges made to te style, placement, nodes or tabular data associated wit map objects. It is a good idea to do tis from time to time after any important canges ave been made. File>Revert Table will take you back to te state of te table wen it was last saved (or to wen it was opened if no canges ave been made).

28 134 REDISTRICTING Redistricting is anoter metod of grouping or combining map objects, but one wic allows a 'wat-if' approac to te task. Wen a redistrict window is opened, MapInfo groups objects into districts and displays information on selected fields for eac district. Objects can be temporarily or permanently reassigned to different districts, and te field values are recalculated immediately. Tis allows one to investigate te effects of moving map objects from one group to anoter. For example, one migt be trying to create scool districts wit equal numbers of pupils; allocate inspectorates wit equal area or wit equal numbers of monuments, sops or factories; or coose reserved land to maximise contiguity wile minimising cost. Redistricting can also be a andy way of temporarily grouping objects to obtain statistics for eac group. Wile tis can be done more flexibly using Query>SQL Select, using Group By and calculating aggregates (page 132), redistricting allows you to see te spatial distribution of te groups created. Creating a redistrict window To carry out redistricting, you must ave a map window open, altoug not necessarily active. Use Window>New Redistrict Window to bring up te New Redistrict Window dialogue: 7 Te Source Table pulldown list will only sow tables wic are displayed on te current active map window or te last map window wic was active (e.g. if a browser as been made active before requesting redistricting). Tis is te map on wic redistricting will be displayed.? MapInfo initially groups te map objects into districts according to te value of te District Field selected from te pulldown list. Te District Field will normally be a field indicating an existing grouping, so tat tere will be several map objects for eac value. However it can be a 6 7 You can only ave one redistrict window open at once.

29 blank field, or a field wit a single value trougout, in wic case MapInfo will create a single district.! BEWARE: If you move an object from one group (district) to anoter, you will cange te value of tis field - tat's ow MapInfo tells wic district an object belongs to. 135 If you want to retain te original value of te district field, you sould add a new field to te table, peraps called Hold_District, using Table>Maintenance>Table Structure (page 40) and set it equal to te field you want to use for districting using Table>Update Column (page 157) before you start redistricting.? If te district field is a field wit a unique value for eac record, suc as an ID or a continuously varying property, you may end up wit a large number of single-object groups. If tis results in more tan 230 districts you will get a warning message and no districts will be created. MapInfo likes to ave at least 4 caracters in te district field, to allow creation of unique district values wen a new district is added (see below), but will allow you to proceed wit a smaller field widt. Fields to Browse will initially sow te name of te District Field selected, Count, and eiter Fill, Line or Symbol, depending on te type of objects being grouped. 8 Additional fields can be added from Available Fields by double clicking te field or igligting and clicking te Add button. Sum and Pct are sown for all numeric fields in te table. Clicking OK brings up te Districts Browser window: Count sows te number of objects grouped togeter to make eac district. Sum sows te sum of te specified field for all objects in te group, wile Pct sows te sum for te group as a percentage of te sum for all groups. It is a pity tat redistricting is limited to te count, sum and percentage aggregates. Average and oter measures of central tendency would be useful aggregates to include. It is also unfortunate tat te values are presented wit a floating decimal point and varying numbers of decimal places, as tis makes te redistrict browser ard to read. Fill, Line or Symbol sows te way in wic te group is represented on te map. Tis can be canged by clicking on te fill, line or symbol in te browser, wic will bring up an appropriate Style dialogue. 8 Were more tan one type of object is selected, MapInfo only displays one style column, an issue glossed over in te manuals wic assume tat you will only ever select one type of object. I am not sure wat algoritm is used to decide wic style is te most appropriate, as it sometimes comes up wit an inappropriate style even wen all te selected objects are of te same type.

30 136 District display on te map window Wen te redistricting browser is displayed, te map objects wic ave been grouped are displayed on te linked map window using te fill, line style or symbol style sown in te browser: MapInfo actually creates an Individual Values tematic layer on te map window, and tis can be modified like any oter tematic map (see capter 8) as well as by clicking on te style in te redistrict browser. Note tat, for te display of districts, te redistricting browser is linked to a single map window (te last active map window at te time te browser was created) wic is were te tematic layer is added. However, selection of objects on oter map windows will ave te same effect as selection on te linked map window. Reallocating objects Wenever a redistrict browser is displayed, one (and only one) of te districts in te browser will be selected (as sown by te solid square at te left of te browser row). Tis is te target district. Wenever an object is selected on te map window, it is temporarily reassigned to te current target district, its fill, line style or symbol cange to te style for te target district, and te fields in te redistrict browser are recalculated and updated. Tis allows you to immediately see te effect of reassigning an object to te target district. Multiple districts can be reassigned by selecting multiple map objects using all te usual tecniques (see capter 5). AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA Once you are satisfied wit te reallocation, you can make te assignment permanent using 6AAAAAAA AAAAAAA AAAAAAA Redistrict>Assign Selected Objects. Tis will permanently cange te value of te District AAAAAAA AAAAAAA Field for te object. AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA!

31 137 Deselecting objects will reallocate tem to teir previous districts. Display style Unfortunately, wen you select districts wic are already saded in different colours (because tey belong to different districts), MapInfo's igligt canges eac colour differently, so it becomes very ard to determine wic districts ave been selected. If you are using a colour display, canging te tematic mapping style to use sading rater tan colour styles (page 198) will allow te igligting to be seen more clearly: Canging te target district Te current target district can be canged in one of two ways. Click on one of te open squares on te left of eac redistrict browser row. Te solid square, indicating selection, will move to tis row; Select one object on a map window and use Redistrict>Set Target District from Map (you will need to make te redistrict browser te active window to make te Redistrict menu entry available). Te target district is reset to te district containing te selected object. Creating new districts Use Redistrict>Add District to create a new district to wic map objects can be allocated. Te new district is initially created wit no objects and te district field value is set automatically (normally DISTxxx were xxx is an incrementing number). Te district field value can be edited in te district browser (see below). Editing te district field As noted previously, any reallocation of objects to a different district canges te value of te district field. Te district field value can also be canged for all objects allocated to a particular district, simply by clicking in te district field in te districts browser and editing te value.

32 138 Removing districts Redistrict>Delete Target District removes te current target district and reallocates all te objects in tat district to te unallocated district (zero or blank value in te district field). It does not delete te objects in te district. Temporarily reassigned objects remain in teir original district. Saving results of redistricting Wen te redistricting window is closed, te corresponding tematic map layer is removed from te linked map window and te original styles are redisplayed. However, te redistricting wic as taken place (i.e. te canges to te value of te redistrict field) are preserved, provided tey are saved using Table>Save. Canges can be removed wit Table>Revert. Browser display options Redistrict>Options allows setting of options for te districts browser window: Districts Sort Order determines te order in wic districts will display in te districts browser. Most recently used keeps te most recently selected target districts at te top of te browser. Alpabetical sorts tem alpabetically - unfortunately, if te district field is a numeric field it still sorts alpabetically, wic means tey are displayed in te order 0, 1, 10, 100, 11, 12,... 2, 20, 21, Unordered applies no sorting. Ceck te Save as Default box to use te selected sorting order in future districts browsers. Sow Grid Lines simply turns on te grid of lines on te browser. AAA 6AAAAAAA

33 139 LABELLING MapInfo provides two functions for labelling objects on te map using values extracted from te tabular data attaced to eac object: te Label tool for labelling of individual objects. Click on te object to be labelled, at te point were te label is required; an Automatic labelling function for labelling all te objects in a layer. Automatic labelling is switced on wit te Label ceck box in te Layer Control dialogue. Labels are part of te map window, not part of te table. Te same objects can be labelled differently on different map windows. Labels are attaced directly to objects and are always editable, weter or not te layer to wic tey are attaced is editable. Labels are always on top of oter objects. Configuring labels Prior to using te label tool or automatic labelling, use Map>Layer Control (Ctrl-L) to configure te labelling function. In te layer control dialogue, igligt te layer containing te objects to be labelled, and click te Label button to display te labelling options for te layer:

34 140 Labelling field Objects can be labelled wit any of te fields defined for te table, or an expression (MapInfo Reference pages ). Tis allows labelling wit unique identifying information suc as names (e.g. site or geograpical names) or identifiers (e.g. site reference number, sampling IDs, object or event codes, street numbers). String functions can be particularly useful as a means of truncating long fields or picking out sort codes from te start or middle of a field, for example: Rigt$(SampleID,4) to pick out te last four caracters of an identifying number. Labels can also be created by concatenating fields, for example: Mapseet+"-"+Sitenum to concatenate te two fields separated by a das (text between "" "" is reproduced verbatim). A line break can be inserted into te label wit Cr$(10). 9 To use an expression for labelling, select Expression... at te bottom of te Source pulldown list. An existing expression can be edited by selecting Expression... again. Coded fields can be used to write a number or abbreviation for eac object on te map as an alternative to te symbols provided by tematic mapping (capter 8). Tis can be quite useful were tere are a large number of values, so tat letters A toug Z or identifying codes may provide a better way of identifying objects tan a pletora of symbols. Te objects temselves can be replaced wit te label by specifying N (no symbol) using te object style dialogue and centring te label (see below). Visibility Custom labels (labels created wit te Label tool or labels dragged away from teir original position or for wic te style or content ave been modified) are always visible. Tey are not affected by te visibility ceck box on te Layer Control dialogue or te visibility settings in te Label Options dialogue.? Automatic labels can be switced on and off by cecking On or Off buttons in te Label Options dialogue, as well as by cecking te Visible box in te Layer Control dialogue, or tey can be displayed witin a particular zoom range (page 82). A red ceck mark (ü) in te labelling column of te Layer Control dialogue indicates tat labels on tat map layer are zoom layered, and tat te map is zoomed outside te range of scales witin wic labels are displayed (pages 81-83). Were tere are many labels te map can become a mess, so MapInfo allows labels to eliminated selectively troug Allow Duplicate Text, Allow Overlapping Text, and Maximum Labels. By uncecking duplicate text, you avoid multiple labelling of, for example, rivers wic ave been recorded in several sort sections. Uncecking overlapping text produces a clean map, but at te cost of losing labels for objects in proximity to one-anoter: tis may be OK were one simply requires some representative labels rater tan systematic labelling. Maximum labels sets an upper limit on te number of labels sown. None of tese options gives te user muc control over wat labels are sown and wic are eliminated. A better option is often to allow bot duplicate and overlapping text, and ten move te labels created to space tem neatly, wit lines or arrow lines back to te objects (see "Styles" below) were tey ave been moved substantially. 9 6 Oter special caracters can be inserted using te ASCII code, for example Cr$(09) = Tab; Cr$(32) = Space; Cr$(34) = Quote (").

35 141 Previewing labels Because labels maintain a constant size relative to te map window, and are generally larger on te screen tan on te printout of a map, 10 it is very ard to position closely spaced labels on a map window. Zooming in srinks te labels relative to te space available, so te result of zooming out again is unpredictable. To obtain a semi WYSIWYG display of te final map, first adjust te map window to te final sape, orientation (portrait or landscape) and coverage of te map. Set te label size to te minimum acceptable for te final map, say 4 point (it is a good idea to use a compact serifed proportional font suc as Times, as you can pack in a maximum amount of legible information in a small space). Don't worry about te appearance of te map, wic is probably a mess of overlapping labels. Now open a Layout window containing one frame for te map window, make sure te layout consists of one page (or more if you intend to print te map over multiple pages) in te same orientation as te map and resize te map frame (olding down Sift so tat its sape doesn't cange) to fill te layout. Position te layout window beside te map window and set it to view te layout at 100% or larger scale (Layout>Cange Zoom). Use Layout>Options and set Sow frame contents to Always - tis will ensure tat te layout window is updated as eac cange is made in te map. If tis proves too slow, cange to Only wen Layout Window is Active, wic means you will ave to activate te layout window after a few canges ave been made to see te effect. You can now adjust te position of te labels on te map and observe te final effect on te layout. Te main difficulties are finding te label you want to move in te mess of labels on te map window (it may elp to pull closely-spaced labels rigt out of te way and ten move tem back one by one) and finding te part of te map you are working on in te layout window. Styles Te text style button allows setting of te font and styles (pages ) to be used for labelling. Altoug MapInfo only sows point sizes down to 8 point in te pulldown list, smaller point sizes can be typed into te dialogue and point sizes around 5-6 are often suitable for labelling large numbers of objects. Smaller point sizes can be used for output on a ig resolution laser printer tan are legible on te screen. Te point size of labels relative to te map window stays constant as te map is zoomed in and out, unlike text objects on map layers, wic get larger as you zoom in (as did labels in MapInfo version 3). See furter discussion on page 119. Wen a label is dragged away from te object labelled, a plain line or an arrowed line can be drawn between te label and te object centroid (or te point labelled wit te Label tool). Ceck te appropriate entry under Label lines. Te style of te connecting line or arrow can also be canged using te line style button. Plain lines generally look better tan arrows if tere are lots of label lines. 10 Since te map window is less tan te wole screen and is terefore nominally only a few inces ig - see footnote page??119.

36 142 Position Labels are positioned relative to te centroid 11 of te object tey are labelling by clicking one of te Ancor Point boxes. Te default 2 point Label Offset between te labels and te objects being labelled is often inadequate for point objects, resulting in a label wic runs into te objects, and sould be increased until te desired effect is obtained. Cecking te Rotate Label wit Line box causes labels to follow te direction of te lines tey are labelling so tat, for example, grid lines in te Y direction will ave text running vertically. Labels, like oter text objects, can be rotated individually, or several labels can be selected and rotated togeter, by dragging te rotation andle situated just below te rigt and end of te text. Seamless map layers Label options applied to a seamless map layer (page 100) apply to all te base tables making up te layer. Missing labels? If you enable labels and find tat only some of your objects ave been labelled, ceck weter Allow Duplicate Text and Allow Overlapping Text ave been enabled (page 140). If tey are not, or if a limit as been specified under Maximum Labels, ten labels will be eliminated from te map in a somewat arbitrary manner. Wen a value is set for maximum labels, labels are displayed in te order in wic te records occur in te table until te maximum number is reaced, ten no furter labels are displayed. If all your labels are missing, look to see weter a zoom range as been specified under Min. Zoom or Max. Zoom. Look for a red ceck mark in te labelling column in te Layer Control dialogue, wic indicates tat te map is outside te range of scales for wic labelling as been enabled (pages 81-83).?? 6 11 Note tat te 'centroid' can be moved by dragging it in object resape mode - see page??.

37 143 CUSTOM LABELS Labels wic ave been modified from te default position and content specified in te Map>Layer Control>Label dialogue, or positioned wit te Label tool (below) are referred to as Custom Labels. Custom labels must be saved by saving a workspace. Modifications override general defaults set in te Label Options dialogue and will not be lost if te defaults are modified. Custom labels are always visible and are not affected by setting label visibility off. Objects can be labelled individually by selecting te Label tool and clicking on te object to be labelled. Labels drawn in tis way are identical to tose drawn wit automatic labelling, but can be individually positioned witin an area object or along a line. Wen an object is already labelled and you click on it wit te Label tool, te existing label is moved to te location were you clicked - you can't get more tan one label for a single object. Were objects overlap, te label is drawn for te uppermost object in te top selectable layer for wic labelling is enabled. Hold down Ctrl wile clicking to cycle troug objects and layers beneat tis (page 87).? If te new label overlaps or duplicates an existing label, and overlapping or duplicate text is not enabled, te existing label(s) will be idden.? If visibility is set to off in te Map>Layer Control>Label Options dialogue, or if no objects exist at te location clicked wit te label tool, a beep will sound. Individual label style Te style of individual labels can be modified by double clicking on te label or selecting it and itting F7. Tis brings up te Label Style dialogue (wic sould really be called te Label Object dialogue):? Tis dialogue allows modification of te label text and style for a single label - it will not display if F7 is pressed wit multiple labels selected. Unlike te normal style dialogues, canges made to te style of an individual label will not affect te style of oter labels or of future text.

38 144 To cange te style of multiple labels, select tem and use Options>Text Style (F8) or te text style button to display te Text Style dialogue (page 118). Canges made in tis dialogue will affect te style of future text. Canging te font style in te Map>Layer Control>Label Options dialogue will modify te font of custom labels as well as te default labels, to ensure tat all labels for a particular layer ave te same text size and font. Oter canges in tis dialogue will only affect te drawing of new labels and te style of non-custom labels. Repositioning and scaling multiple labels Te labels created by automatic labelling may require systematic displacement. For example, wen labelling a grid, labels on te orizontal and vertical grid lines will often require different alignments. To move multiple labels, proceed as follows (labelling of a grid is used as illustration): 1. Select te labels to be moved using normal selection tools: 2. (Optionally) zoom in on a small area (one or two grid squares if labelling grids, as in tis example): 3. Wit te Select tool drag te labels to teir correct position relative to te objects being labelled. Wen multiple objects are selected, all objects are moved by te same amount. Tis is true weter or not all te selected objects are visible on te screen. 4. Zoom out and repeat for oter labels to be moved.

39 145 Saving labels! Te labelling status of a map layer is not part of te table itself but part of te map window. In particular, wen labels are repositioned or oterwise modified, te canges are not saved as part of te table. To save tem you must save a workspace. If you do not, te original labelling and your canges will bot be lost. MapInfo will warn you tat canges are going to be lost wen you try and close te map window, remove te layer or close te table, but it may not be obvious by ten wat te warning message refers to. So it is a good idea to save te workspace as soon as labels ave been added or modified, and to resave it wenever tey are furter customised.! Custom labels are invalidated by packing te tabular data (Table>Maintenance>Pack Table) on wic tey ave been created, because MapInfo uses te record number in te table to identify te labelling instructions in te workspace file. Removing labelling If no canges ave been made to labelling, it can simply be turned off in te Layer Control dialogue. If canges ave been made, tese will be stored in any workspaces you save. To avoid tis, or to return all labels to teir default position and style, use Map>Clear Custom Labels to get rid of labels you ave moved or modified. Old-style labelling Labelling was canged substantially between version 3 and version 4. Version 3 style labelling is available troug te MapBasic program AUTOLBL.MBX, supplied wit MapInfo.

40 146 SCALEBARS AND DISTANCE Te MapBasic program SCALEBAR.MBX, supplied wit MapInfo, adds a button to te Tools toolbar and a Scalebar entry to te Tools menu. Click te button and ten click on te map to indicate were te scale bar is to be drawn (te bottom left of te scale bar will be placed at te point indicated). Te scalebar dialogue is sown on te left, and an example of a scalebar on te rigt: Te dialogue comes up wit a default lengt in miles based on te area covered by te map window. Te value can be modified, but it is generally a good idea to stay witin te same ballpark lengt as bot te scalebar tickness and lettering are scaled proportionate to te lengt. A muc smaller value will lead to a tiny illegible scalebar wile a muc larger value will produce an overpowering scalebar. Te scale bar is drawn as a series of separate objects in te cosmetic layer (wic is automatically made te editable layer). Eac element of te scale bar can be modified separately. Tis can be useful for modifying te spelling of te units (e.g. kilometres, kilometres or kms) and te number of divisions labelled. To move te scalebar, select all te elements wit a marquee select, and drag to a new location. Scalebars do not come out well on some eart projections, and may become very distorted wen moved to a different location. Tere is no real solution to tis problem.? Measuring distances Clicking on te Ruler icon measuring tool: activates a floating distance window and te distance Wen you click on successive points in a map or layout window, te distance window sows te distance from te last point clicked and te total distance between all te points clicked, in te measurement units selected. Measurement units are set troug Map>Options>Distance Units for map windows and Options>Preferences>System Settings>Paper and Layout Units for layout windows. Te distances measured on eart maps are great circle distances. On layouts, tey are distances in layout units (i.e. distance on te printed output). Double click on te map or layout to alt te measuring process. Te measuring tool remains active and can be used to make a new set of measurements. Te distance window remains as a floating window even wen a different tool is selected - double click its window control box to close it.

41 147 BUFFERING OBJECTS Te Objects>Buffer command is used to create buffer areas around point, line or area objects. Buffer areas are drawn as polygon area objects wose outline is a given distance away from te object: Buffers can be used to indicate speres of influence or areas witin a given distance of a feature or features, or simply to indicate te size or oter caracteristic of eac object (altoug tis may be better done troug te graduated symbols option in tematic mapping). Buffer objects may in turn be used to select oter objects wic lie witin te zone of influence or given distance of te features of interest. Before buffering objects you must: Select te objects to be buffered, using any of te normal selection metods (capter 5); Create a new layer on te map window (wic will default to te editable layer) or make one of te existing layers editable (buffers are created in te current editable layer). Te buffering dialogue box gives a variety of buffering options:

42 148 Te Value option allows buffers of a fixed radius (left-and illustration below) as one migt use to establis all areas witin a given proximity of roads. Te From Column option varies te radius of te buffer according to some caracteristic of te object as recorded in te tabular data (rigt-and illustration below). Te From Column option can be used to weigt te buffering towards particular classes of object (e.g. larger buffers for major rivers tan small creeks, larger buffers around wilderness tan recreation areas) or simply to represent te importance of objects (e.g. stream order, size or significance of sites, transmitter power or retail outlet size). Variable radius buffering can also be based on an expression, wic may in turn include spatial information. For example, buffer size could be dependant on te area of te object or its inverse, or on its proximity to some oter features. If you select One buffer for eac object a separate buffer is created around eac object (a series of point objects in tis example): Fixed distance (Value) Variable distance (From Column) If One buffer of all objects is cecked, any overlapping buffer objects are combined into a single buffer object: Buffers are polygon objects created in te current editable layer. If you want to be able to see te buffered objects on te map, ensure tat te editable layer is below te layer containing te objects being buffered, or tat te default region style is transparent, oterwise te buffers will obscure te objects. If te objects being buffered are temselves in te editable layer, te buffers will be drawn on top of te objects and may obscure tem. To see map objects obscured by te buffers, set te fill style for te buffers to no fill or use a patterned fill and set te background to transparent - see Region Style page 118). Smootness relates to te number of segments used for eac 360 degree arc in te polygon. Increasing tis value will generate a more accurate (less angular) buffer at te expense of speed.?

43 149 CONCENTRIC BUFFERS Concentric buffers can be used in many instances were one is interested in areas of suitability or distance bands from features suc as communication routes, transmission towers or azards. For example, to obtain a istogram of distance of points from features of interest: buffer te features concentrically (see below); carry out a point-witin-polygon join (page 174); calculate an aggregate (count) for eac buffer zone (page 177); plot a grap of te counts (page 201). Te MapBasic program R_BUFFER.MBX, supplied wit MapInfo, adds a menu entry to te Tools menu wic serves to create concentric buffers at specified distance around one or more objects. Select te objects wic you want buffered before using Tools>Concentric Ring Buffers>Create Ring Buffers to bring up te following dialogue: Specify te buffering distances for eac buffer using te Radius and Units fields, and click te Add Ring button. Tere is no way of removing buffer rings, so if you make mistakes you ave to click te Clear button and start again. Te style and smootness settings relate to all buffers created - if you require different styles for eac buffer radius, tey must be set after te buffers ave been created. Concentric buffers are created in a layer called Buffer_Layer. Rename tis layer to avoid it being overwritten in a future buffering operation, or cut and paste tem into anoter layer (page 113). Were multiple objects are buffered, R_BUFFER creates a single buffer for all objects for eac of te buffering distances specified, wic can be extremely slow. 12 Unfortunately te tabular data attaced to te buffer objects, wic consists of a single field Id, is set to te value 0 rater tan being updated wit te buffering distance. You may wis to edit te tabular data after te buffers ave been created using te Info tool or a browser.? Buffering can be a very slow process wen large numbers of objects (particularly line or area objects) are involved. Wile it is possible to create concentric buffers by buffering buffers, it sould be borne in mind tat eac set of buffers contains many more nodes/line segments tan te preceding set, resulting in greatly increased buffering time, possibly running into ours or even days. Concentric buffers sould terefore be created by repeatedly buffering te original objects, as outlined in DISTBUFF.TXT (see footnote). 12 Instructions for manual creation of concentric buffers and speeding up te process are available from te Sydney University Arcaeological Computing Laboratory FTP site (ftp://felix.antiquity.arts.su.edu.au/pub/texts/distbuff.txt).