DatuGram 2D User Guide Version 2.0 August 2013 Datumate Geomatics Expert Systems
Using DatuGram, land surveying is made easier, faster and with excellent geodetic accuracy. For more information please visit our website at www.datumate.com, or contact us at support@datumate.com. 2011-2013 by Datumate, Ltd. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of Datumate, Ltd. - 1 -
Contents 1 Using this Document... 3 2 Overview of DatuGram TM 2D... 4 2.1 Background... 4 2.2 Principles of Operation... 4 2.3 Working with DatuGram TM 2D... 4 2.4 Accuracy of Measurements... 6 3 Installing DatuGram 2D... 8 3.1 System Requirements... 8 3.2 Installing DatuGram TM 2D... 8 3.3 Activating DatuGram TM 2D... 9 3.4 Reinstalling DatuGram TM 2D... 10 3.5 Transferring DatuGram TM 2D to a Different Computer... 10 3.6 Upgrading DatuGram TM 2D... 11 4 Field Work: Taking Photos and Making Anchor Points... 12 4.1 Choosing your Camera and Lens... 12 4.2 Planning Your Field Work... 12 4.3 Photographing Façades... 13 4.4 Measuring Reference Anchor Points on Façades... 14 4.5 Before Returning from the Field... 16 5 Working with DatuGram TM 2D... 17 5.1 Step 1: Opening a Job... 17 5.1.1 Opening a New Job... 17 5.1.2 Opening an Existing Job... 18 5.2 Step 2: Loading Images... 19 5.3 Step 3: Creating a Datum Plane... 20 5.3.1 Creating a New Datum Plane... 20 5.3.2 Deleting a Datum Plane... 21 5.4 Step 4: Anchoring the Datum Plane... 21 5.4.1 Select a Datum Plane... 22 5.4.2 Load the TPS Measurement File... 22 5.4.3 Crop the Image... 25 5.4.4 Anchor the Image... 25 5.5 Step 5: Generate the Ortho-photo... 28 5.6 Step 6: Draw on the Ortho-photo... 30 5.6.1 Highlighting Points Measured in the Field... 30 5.6.2 Drawing Layers on the Rectified Ortho-image... 30 5.6.3 Editing Layers and Elements... 32 5.7 Step 7: Export to CAD Software... 33 6 Measurement Quality Control... 39 7 Generating Reports... 40-2 -
1 Using this Document The DatuGram TM 2D version 2.0 User Guide will help you: Understand the principles of operation of the software. Plan and execute your field work. Use the software and make measurements from the images in the office. Within this document you will find comments, tips, and answers to frequently asked questions. These are indicated by the following admonitions: This icon signifies comments that are important for the user. They will help you to make maximum use of the DatuGram 2D software. This icon signifies operational tips that may help you optimize your work in the field and in the office. This icon signifies answers to frequently asked questions that have been posed by users of DatuGram 2D. - 3 -
2 Overview of DatuGram TM 2D 2.1 Background DatuGram TM 2D software is used by land surveyors to make accurate geodetic measurements from images created using regular digital cameras in survey projects of flat surfaces, i.e., in surveys in which most of the points reside on a known common plane, such as on flat building facades or internal walls. Another common use of DatuGram TM 2D is the digitization of hardcopies of geodetic plans and maps. 2.2 Principles of Operation DatuGram TM 2D employs the principles of rectified ortho-photos. An ortho-photo is an image that is geometrically corrected ("ortho-rectified") relative to the image orientation angle, camera tilt, and lens distortion so that the scale is uniform across the rectified image. After scaling the ortho-photo with several anchor points of known positions, true coordinates and distances can be measured from it and technical drawings can be directly drawn based upon it. DatuGram 2D fits a reference plane (called a datum plane ) to the anchoring points on the original image using the least-square best-fit method, and then employs an advanced image rectification algorithm that resamples every pixel of the original image. This method of image rectification generates ortho-photos with very high accuracy, maintaining the exact true shape and color of all the elements in the image. As a result, surfaces such as building façades may be photographed from highly oblique angles, allowing the surveyor to overcome any obstructions in front of the buildings, or facades of high-rise buildings may be photographed across narrow streets, while maintaining high accuracy of the rectified ortho-photo. 2.3 Working with DatuGram TM 2D Working with DatuGram TM 2D is very simple. - 4 -
In the field, the land surveyor first photographs the flat surface he wants to survey, such as a building façade. Using a Total Positioning Station (TPS) he then measures the coordinates of several (minimum of five) reference points on the façade, in either a local or national grid. These reference points will later be used to anchor and rectify the image, i.e. creating an accurate ortho-photo of the building façade. In the office, the surveyor uploads the façade image and the TPS measurement file of the positions of the anchor reference points to the DatuGram TM 2D software. The DatuGram TM 2D software prompts the surveyor to locate the reference points in the façade s image. Once this is done, the software verifies the accuracy of the anchoring reference points by fitting a plane through the reference points (a datum plane ) using the least-square method, and verifying that the residual distances of the reference points from the plane are sufficiently small. The software then prompts the surveyor to proceed and creates a highly-accurate rectified orthophoto of the building façade. Once the rectified orthophotos image is created, the surveyor can draw a technical drawing of the façade directly on the rectified image. The output is a.dxf file of the drawn layers (polygons, polylines, and point objects) which may be further processed in any CAD software. Alternatively, the surveyor may directly export the rectified ortho-photo image of the façade to any CAD software, and there create the technical drawing on the image. In this case the DatuGram TM 2D software provides a.dxf file with the exact scaled grid of the image, and all that the surveyor needs to do is snap the image to the scaled grid, and then start drawing on the scaled image. - 5 -
In addition, the surveyor may opt to light up, on the rectified ortho-photo, all the points that were measured in the field by the field team. This permits the surveyor to verify the quality of the measurements that were undertaken by the field team to a sub-centimeter accuracy. 2.4 Accuracy of Measurements The accuracy of measurements made on the rectified orthophotos generated by DatuGram 2D depends on the resolution of the camera and distance from the measured object. An 8-megapixel camera provides sub-c centimeter accuracy to a distance of about 50 meters, while a 20-megapixel camera provides the same accuracy to a distance of about 120 meters. A second determinant factor for the maximum accuracy of measurements is the accuracy of measuring the coordinates of the anchor points on the façade using the TPS device. This should be as precise as possible as it sets a baseline accuracy for all the measurements and drawings from the images. The maximum measurement accuracy may also be affected by the level of scattering of the anchor points in the image, as well as the accuracy of pinpointing the anchoring points in the image. The maximum measurement accuracy is attained by maximally scattering the anchor points on the façade, i.e., choosing anchor points so that four anchor points are at the corners of the image, and a fifth anchor point is in the middle of the image. For more details, see Chapter 4. Q: How would I know the maximum accuracy of my measurements? After rectifying the original image into an ortho-photo, an Image Accuracy Indicator appears in the right lower corner of the Planes screen. The color of the Image Accuracy Indicator is green if the measurement accuracy is good, yellow if measurement accuracy is fair, and red if measurement accuracy is poor. The software is pre-configured to a default setting such that a good measurement s accuracy is better than 3 cm, a fair measurement s accuracy is 3-5 cm, and a poor measurement s accuracy is greater than 5 cm. These default settings are user- - 6 -
adjustable. The reasons for inaccuracies can often be found in the Quality Control Report. For more details, see Chapter 6. - 7 -
3 Installing DatuGram 2D 3.1 System Requirements The DatuGram TM 2D software is designed to work on common office PCs and standard laptops Operating System Requirements o Windows XP Professional or Home edition (SP3 or later): CPU RAM: Minimum 2GB RAM; recommended 3GB RAM. o Windows 7 Enterprise, Ultimate, Professional, or Home Premium: CPU RAM: Minimum 4GB RAM; recommended 8GB. o Windows 8 Enterprise, Ultimate, Professional, or Home Premium: CPU RAM: Minimum 4GB RAM; recommended 8GB. CPU and Hard Disk Requirements o CPU: minimum Intel core I3 (or equivalent); recommended I5. o Hard disk: minimum 10GB of free space; recommended 20GB. Screen and Graphics Card Requirements o Display resolution: at least 1,280x768 with True Color; recommended 1,600x960. o Graphics card: at least 0.5GB, recommended 1GB Connectivity Requirements o Available Internet connection for installation, activation and upgrades. Compatibility o DXF file formats: DXF 2006 onwards. 3.2 Installing DatuGram TM 2D DatuGram TM 2D is installed by running the DatuGram TM 2D Software Installation CD, or through an installation link sent to you. The installer application will guide you through the steps required to install DatuGram TM 2D on your computer: 1. When the Software Installation dialog box appears, click Start Installation. - 8 -
2. When the DatuGram TM 2D Setup Wizard dialog box appears, click Next. 3. When the License Agreement dialog box appears, click I Agree and click Next. 4. When the Select Installation Folder dialog appears, choose the folder and click Next. 5. When the Confirm Installation dialog box appears, click Next. During software installation, depending on your operating system, you may be requested to confirm installation of the DatuGram TM 2D software on your computer. DatuGram TM 2D utilizes various operating system resources, including Microsoft.Net Framework and C++ Redistributable. If these operating system components are not available on your computer, the installation process will automatically download and install them for you. Depending on your operating system, you may be requested to confirm their installation on your computer. 3.3 Activating DatuGram TM 2D If this is the first time the software is installed on that computer, you will be asked to activate your software license. 1. When the License Request dialog box appears, fill in all the fields of the form and click Send Request. - 9 -
You will receive your license activation code by email. This may take up to one business day. The license request requires Internet connectivity. Make sure you have proper internet connectivity before sending the license request. 2. Upon receiving your license activation code by mail, copy it to the License Activation dialog box, and click Activate. Each software license allows you to install the software on a single computer. Any attempt to install the software on a second computer, prior to uninstalling it on the first one, will immediately revoke the validity of the software license. Q: Is there a limit on the number of times I can install the software from the installation disk? No. You may reinstall the software on your computer any number of times. 3.4 Reinstalling DatuGram TM 2D You may reinstall DatuGram TM 2D on the same computer any number of times. The installation process is identical to the initial installation process, and no activation is required. However, if any hardware changes have been made on that PC, such as CPU or hard disk upgrades, you may need to re-activate the software license. 3.5 Transferring DatuGram TM 2D to a Different Computer Each software license allows you to install the software on a single computer. You may transfer the software from one computer to another computer by first uninstalling and then reinstalling it. When installing the software on the new computer, you will need to re-activate the software license. - 10 -
Any attempt to install the software on a second computer, prior to uninstalling it on the first one, will immediately revoke the validity of the software license. 3.6 Upgrading DatuGram TM 2D Datumate periodically releases software upgrades for DatuGRam TM 2D. These upgrades include new functionality, compatibility to new operating system versions, bug fixes, and more. These upgrades are available for customers who are registered with Datumate s Annual Support and Upgrade Program. If you are eligible for software upgrades, it is highly recommended to install them upon their release by Datumate. To check whether there are new software versions, click Help in the main menu and click Check for Updates. The software will check the availability of new versions, and, if available, will automatically download and install them. Depending on the configuration of your operating system, you may be requested to confirm their installation on your computer. Checking for the availability of new versions requires Internet connectivity to Datumate s website www.datumate.com. Please make sure you have proper Internet connectivity, and that your local Firewall does not block HTTP connection with Datumate s website. Check for new versions on a regular basis, and at least once per quarter. - 11 -
4 Field Work: Taking Photos and Making Anchor Points 4.1 Choosing your Camera and Lens Use a high-resolution camera. Any regular digital camera with sufficient resolution relative to the required accuracy and distance of the objects may be used. You may use a DSLR (Digital Single Lens Reflex) or point-and-shoot camera, or even the camera in your smartphone (if it has sufficiently good resolution). An 8-megapixel camera provides sub-centimeter accuracy to a distance of about 50 meters, while a 20-megapixel camera provides the same accuracy to a distance of about 120 meters. Use a wide-angle lens (focal length less than 24mm). The wide-angle provides a wide field of view (FOV), allowing capturing a wide area from closer distances. This enhances the quality of measurements for images. Use as wide an angle lens as possible, i.e., with a focal length as small as possible, thus providing a wide field of view. The wider the FOV, the easier it will be to fit long or tall facades - across the limited distance of narrow streets - into a single image. Q: So which camera should I choose? It is recommended to use a digital camera with at least an 8 megapixel resolution, equipped with a focal lens smaller than 24mm. 4.2 Planning Your Field Work Plan to avoid foreground obstructions. It is advisable to plan in advance the photographing and the measurements of the anchor points on the facade. Anticipating in advance any foreground obstructions that may hamper photographing and measuring anchor points with the TPS will significantly shorten the time spent in the field. Plan your anchor points in advance. If you already have an image of the façade, print it and mark on it the anchor points that the field team should measure. The printed image will thus replace the need for a manually drawn field sketch. This will save field time and possible errors in correctly identifying the measured anchor points. Plan the route to minimize travel time. Your field team may photograph and measure anchor points of multiple facades in a single work day. Plan the route of the team to minimize travel time between survey areas. - 12 -
Make sure that your equipment is fully charged and ready. Before starting out, make sure your TPS and camera are fully charged and all your gear is in order. In some locations, services such as Google Street View may provide low-resolution images of the facades of buildings. They can be used to plan your field work. 4.3 Photographing Façades Choose a photographing angle that will minimize foreground obstruction. The optimal angle to photograph the façade is directly perpendicular to the façade. However, you may want to choose a different photographing angle to minimize any foreground obstructions in the image, such as trees, fences, parked cars, etc. You may photograph the façade at any angle greater than 45 from the façade. Sector not recommended for photographing Recommended sector for photographing Surveyed façade 45 45 Sector not recommended for photographing Building viewed from above Try to take your photographs from an elevated area. To minimize foreground obstructions, try to take your photographs from an elevated area such as the roof of a building overlooking the survey area, or use an elevated platform for photography such as a tall monopod to elevate the camera few meters above ground level. Try to fit the whole façade into one image. Using a wide-angle lens with a focal length smaller than 24 mm will help fit the façade into one image, even across the limited distance of a narrow street. The following pictures are examples of images taken with a wide-angle lens across narrow streets. - 13 -
Q: What should I do if the whole façade does not fit into a single image? Sometimes you may not be able to fit the whole façade into one image, such as in case of a very tall or wide façade, or a very narrow street. In these cases, make several overlapping photographs of the façade, and measure anchor points for each image. Process each image separately in DatuGramTM2D by anchoring and rectifying it, and finally paste together the rectified images (which share exactly the same scale) in your CAD software. 4.4 Measuring Reference Anchor Points on Façades Measure at least five anchor points. After photographing the façade, measure with a TPS device, the positions of at least five reference anchor points that are well-scattered on the flat surface you want to measure. You may measure point coordinates in either a local or a national grid. Choose well-defined anchor points. Choose anchor points that are unambiguously and accurately identifiable in the image. Scatter the anchor points. To attain maximum accuracy, scatter the anchor points on the façade, i.e., choose anchor points so that four points are at the corners of the image, and a fifth anchor point is in the middle of the image. Reference anchor points Façade viewed from the front - 14 -
Choose anchor points that lie on the same surface. It is essential to choose anchor points that lie on the flat surface you wish to use for image rectification and measurements. This will usually be the surface of the external wall of the façade. Choosing anchor points that do not lie on the same flat surface will degrade the accuracy of measurements from the rectified images. Handling multiple planes on the façade. In some cases, such as that illustrated in the following figure, there may be more than one datum plane on the façade. In this case, separately measure anchor points for each of the planes. Then, separately process each plane in DatuGram TM 2D by anchoring and rectifying it, and finally paste together the rectified images (which share exactly the same scale) in your CAD software. Façade viewed from the front Plane #1 Plane #2 Handling elements that protrude out of the façade. As depicted in the following image, many relatively flat facades, include elements that protrude out of the datum plane, such as balconies, ledges, cornices, etc. - 15 -
Any element that protrudes out of the datum plane of the flat façade will not be appropriately rectified, and its shape will not be maintained in the ortho-image. To handle a protruding element, while in the field, measure the positions of points on the protrusion. DatuGram TM 2D will correctly project these measured points onto the datum plane of the rectified image, so that they will appear in appropriate form in your technical drawing. Protruding element Façade viewed from the front 4.5 Before Returning from the Field Before leaving the field, make sure you have: Images of the façade. TPS measurement file of your anchor points. Field sketch (or image) detailing the exact anchor points measured on the façade. Field book with any additional data you need for processing the job: building address, time and date of work, photographing equipment (camera and lens), etc. - 16 -
5 Working with DatuGram TM 2D 5.1 Step 1: Opening a Job 5.1.1 Opening a New Job The first step of working with DatuGram TM 2D upon your return from the field with photographs and measurements of a new façade is to open a new job. 1. Click File > New 2D Job in the main menu of DatuGram TM 2D, and or use the shortcut Ctrl+N. 2. Fill in the required information in the Job Properties dialog box and click OK. - 17 -
For easier retrieval of jobs, use a standard naming convention that includes information such as the façade address, date of photograph, camera model and lens focal length: CityName_StreetName_Date_Canon600D_24mm. 5.1.2 Opening an Existing Job To open an existing job: 1. Click File > Open Job in the main menu of DatuGram TM 2D, or use the shortcut Ctrl+O. 2. When the File Open dialog box appears, open the DatuGram TM 2D Jobs folder, choose the appropriate job folder, select the Job file, and click Open. - 18 -
5.2 Step 2: Loading Images After opening a new job load from your camera the image of the façade that was photographed in the field. 1. In the Images screen, click Load Images. 2. The File Open dialog box is displayed. Click the folder that contains the images taken in the field, choose the appropriate image, and click Open. - 19 -
3. After loading images, at any stage you may return to the Images screen and add more images by clicking Add More Images in the lower left corner of the Images screen. 5.3 Step 3: Creating a Datum Plane 5.3.1 Creating a New Datum Plane To define a datum plane on the façade on which the ortho-photo will be rectified, perform the following: 1. Click Planes in the Toolbar, and choose the image you want to work on from the image ribbon at the bottom of the screen. The image will now appear in the Planes screen. 2. Click the + button to add a new datum plane in the image. 3. In the New Plane dialog box, provide a name for the new datum plane and click OK. - 20 -
4. The new datum plane will now appear in the left lower side of the screen. For easier retrieval of planes, use a standard naming convention that includes information such as the job name and the face of the building: JobName_BuildingFace_## You may want to define more than one datum plane on the image, for example if the facade includes more than one flat surface. To add additional planes in the image, click the + button which facilitates adding a new datum plane. 5.3.2 Deleting a Datum Plane To delete a datum plane: 1. Select a plane, right-click on it, and click Delete. Deleting a datum plane will also delete the rectified ortho-photo and any drawings that are based on it. 5.4 Step 4: Anchoring the Datum Plane To anchor the datum plane to the reference anchor points whose positions on the façade were previously measured with a TPS device, perform the following steps which are discussed in detail below: Select one of the datum planes. Load your TPS measurement file. Crop the image. - 21 -
Anchor the image to the reference anchor points measured on the façade. 5.4.1 Select a Datum Plane To select a datum plane: 1. Click on a datum planes to select it. The selected datum plane will appear with an orange outline. 5.4.2 Load the TPS Measurement File To load the TPS Measurement file: 1. Click Import to load the TPS measurement file. When the File Open dialog appears, choose the measurements file and click Open. - 22 -
The TPS measurement file should be in either a.txt,.csv or.xls format, and should include four fields per point: the point s name followed by three coordinates, with the point s height being the last field. Values may be separated by a space, comma, or semicolon. Q: I am unable to click Import to load my TPS measurement file. Check whether you selected a datum plane. You must choose a datum plane before loading your TPS measurement file. As long as a datum plane has not been selected, the following message will appear: Select a plane from the list on the left panel, or create a new one. After opening your TPS measurement file, the list of points measured in the field will appear in the left upper corner of the Planes screen. - 23 -
2. Right-click on any of the points in the list to open a dialog box that permits editing the list of points. o Click Rename to rename the point s name. o Click Delete to remove a point from the list. o Click Proprieties to manually edit the point coordinates. 3. To search for a specific point use the Point Search box, or manually add a new point using the + button below the list of points. - 24 -
5.4.3 Crop the Image To crop the area of interest in the image, i.e., the area that will be shown in the rectified orthophoto: 1. Click the Crop button and drag the four orange dots on the image so that the area of interest will be inside the white dashed square. 5.4.4 Anchor the Image To anchor the datum plane to the reference anchor points measured by the TPS: - 25 -
1. Click the Zoom button. A blue rectangle cursor will appear on the image. 2. Move the blue rectangle cursor across the image and position it over one of the reference points. When moving the cursor over the image, a zoom-in image appears in the Zoom-in window on the right upper corner of the screen. 3. Click on the position to lock the Zoom-in window. A Zoom-lock indicator on the image indicates the image is locked. 4. Move the cursor to the Zoom-in window and click on the pixel of the point. You may further zoom-in using the scroll button on your mouse. 5. When the Mark Control Point dialog box appears, choose the point from the drop down menu of the point names, and click OK: 6. Repeat this process until you marked at least five reference anchor points on the datum plane. Inaccurate marking of reference points will degrade the accuracy of the rectified ortho-image. Mark reference points as accurately as possible. You may edit the reference anchor points at any stage: revise their positions, replace points, or delete them from the datum plane. To edit the position of a reference points: - 26 -
1. Click the Point Edit button. 2. Move the cursor across the image and click on the icon of the point you want to edit. This will lock the image (as indicated by the Zoom Lock-in Indicator), and will show the reference point in the Zoom-in window. 3. You may use your mouse or your keyboard arrow keys to move the position of the reference point in the Zoom-in window. To rename, delete, replace or manually edit the coordinates of the reference points: 1. Right-click on the point s icon in the image. 2. Click Rename to rename a point without changing its coordinates. 3. Click Replace to replace the point s name and coordinates with one of the points in the TPS measurement file. 4. Click Delete to delete the point from the datum plane or from the entire job. 5. Click Properties to manually edit the point s coordinates. Revising the position or coordinates of a reference anchor point after an ortho-photo has been generated (see Section 5.5) will delete the ortho-photo and all the drawings that are based on it. This is because a new rectified ortho-photo must be generated after the reference anchor point was revised. The following message will appear whenever the position or coordinates of a reference anchor point are revised after an ortho-photo was generated. - 27 -
5.5 Step 5: Generate the Ortho-photo To generate the ortho-photo: 1. Click the Image Rectification button (labeled Datumate ) to rectify the image according to the anchored datum plane and create an ortho-photo. 2. When the following dialog box appears, click OK. The Layers screen automatically opens with the rectified ortho-photo. - 28 -
Q: After anchoring the datum plane and rectifying the image, I got a completely distorted ortho-photo. There is a mistake in one or more of the reference anchor points. Go back to the Planes screen, verify that you uploaded the correct TPS measurement file, and find the faulty reference anchor point(s) by comparing them to the field sketch. Q: After anchoring the datum plane and rectifying the image, I got an ortho-photo of only a small part of the image. The reason for that is that you did not crop your image. Go back to the Planes screen and crop your image (see Section 5.4.3). After generating the ortho-photo, an Image Accuracy Indicator appears in the lower right corner of the Planes screen. The color of the Image Accuracy Indicator is green if the measurement accuracy is good, yellow if measurement accuracy is fair, and red if measurement accuracy is poor. The software is pre-configured to a default setting such that a good measurement s accuracy is better than 3 cm, a fair measurement s accuracy is 3-5 cm, and a poor measurement s accuracy is greater than 5 cm. These default settings are useradjustable. The reasons for inaccuracies can often be found in the Quality Control Report. For more details, see Chapter 6. - 29 -
5.6 Step 6: Draw on the Ortho-photo To draw layers on the rectified ortho-photo, start by highlighting all the points measured by the TPS in the field on the rectified ortho-photo, and then draw layers on the ortho-photo. 5.6.1 Highlighting Points Measured in the Field To highlight the points measured in the field on the rectified ortho-photo: 1. Click the Enable point locator checkbox in the Points window in the upper right corner of the screen. 2. Select from the list either a specific point, multiple points (using the Shift key on your keyboard), or all the points (by choosing Select All). This will display all the points measured in the field as small red crosses projected on the rectified ortho-photo image. 3. To include the point names, click the Show Names checkbox. All the points measured in the field will be projected onto the datum plane of the ortho-photo. This also includes all points measured on objects protruding from the datum plane such as balconies, ledges, or cornices, thus allowing you to use them in your technical drawing. 5.6.2 Drawing Layers on the Rectified Ortho-image To prepare a technical drawing of multiple layers directly on the rectified image: 1. Select the + button in the Layer window to define a new layer. - 30 -
2. When the Layer Properties dialog box is displayed, name the new layer, select its desired color, and its desired type. A Layer type may be: o Polygon (Area): For objects with an area such as windows, wall coverings, etc. o Polyline (Distance): for objects with a length, such as hanging cables, wall cracks, etc. o Points (Count): for elements that should be counted, such as air conditioners, etc. You may draw multiple elements in each layer. As you draw a new element in a layer, it will be added in the Material Quantities window in the right lower corner of the screen, with its appropriate unit of measure (area, length, or count). The following image shows the windows and cables layers and includes multiple elements. - 31 -
5.6.3 Editing Layers and Elements Various editing functions can be performed on layers and elements. To modify a layer s color: 1. Click the Color field of the layer in the Layers window. 2. In the Color dialog box select a new color and click OK. To modify the name of a layer: 1. Click the Name field of the layer in the Layers window, and edit the name, or click its name field in the Material Quantity window, and edit the name. To delete a layer from the drawing: 1. Click the layer in the Layers window, and click x in the lower left corner of the window, or click the element in the Material Quantity window (or click on the element in the drawing on the image), and click x in the lower left corner of the window. To highlight the names of the elements on the image: 1. Click the Show Text checkbox in the lower right corner of the Material Quantity window. - 32 -
5.7 Step 7: Export to CAD Software DatuGram TM 2D supports DXF 2006 data file format and higher. To export a rectified ortho-photo and your technical drawings to CAD software for further processing, perform the following steps: 1. To export your technical drawings in DXF format, Right click on the image of the layer to export, and click Export to DXF File. When the dialog box opens, select the desired folder to save the DXF file and click OK. This should be done even if you did not create a layer on the image as the DXF file includes the scaled outline of the ortho-photo, which will help you in scaling the rectified ortho-image in the CAD software. 2. To export your rectified ortho-photo in JPEG format, right click on the image of the layer to export, and click Export Ortho-Photo. When the dialog box opens, select the desired folder in which the rectified ortho-photo image will be saved and click OK. 3. Open the CAD software, and import the DXF file. As the DXF file opens, you see a blue rectangle of the scaled outline of the ortho-photo image. Import the JPEG file of the rectified ortho-photo into the CAD software, and scale it by snapping it to the scaled outline of the image (the blue rectangle). The rectified ortho-photo image of the façade is now available for drawings and measurements. By sending it to the back you may see, on top of it, any layer you have already drawn on it in DatuGram TM 2D. The procedure for opening the DXF file, and anchoring and scaling the ortho-photo for users of AutoCAD 2006 version and higher is as follows: 1. Open the AutoCAD application. - 33 -
2. In the File menu, select DXF as Files of Type, click your DXF file, and click Open. 3. You will now see the points and layers you have drawn on the ortho-photo in DatuGram TM 2D. Note that all the points are already projected on the datum plane of the ortho-photo. In some AutoCAD versions you may need to select Zoom > Extend in order to show the whole file. 4. To better view the points, click Format >Point Style to change the way the points are presented on the screen. - 34 -
5. You will see a blue rectangle on the screen. This blue rectangle is the scaled outline of the rectified ortho-photo of the façade. 6. To import the JPEG file of the rectified ortho-photo of the façade, click Insert> Raster Image Reference. 7. In the Attach Image dialog box, click the checkboxes Specify on Screen for both Insertion Point and Scale options, set Rotation Angle to zero, and click OK: - 35 -
8. Click the lower left corner of the blue rectangle that outlines the image scale, stretch to the right upper corner and left-click the mouse. 9. Choose the ortho-photo image that is already on the screen, hold its right upper corner left-clicking on it, and drag it to the right upper corner of the blue rectangle. This will appropriately anchor and scale the ortho-image to the DXF layers. - 36 -
10. Right-click on the image and click Draw Order > Send to Back to send the image to the background, allowing the user to see the DXF layers and draw new layers on the image. - 37 -
It is recommended to insert the image in an Image Bound layer that already exists in the DXF file, so that they will be saved together from now on. - 38 -
6 Measurement Quality Control After rectifying the image of the façade into an ortho-photo, an Image Accuracy Indicator appears in the lower right corner of the Planes screen: The color of the Image Accuracy Indicator indicates the accuracy of measurements on the ortho-photo: it is green if the measurement accuracy is good, yellow if measurement accuracy is fair, and red if measurement accuracy is poor. This is based on how well the datum plane fits to the anchor reference points after the least-square procedure. The software is pre-configured to a default setting such that a good measurement s accuracy is better than 3 cm, a fair measurement s accuracy is 3-5 cm, and a poor measurement s accuracy is greater than 5 cm. These default settings are user-adjustable. To view a detailed report about image accuracy, click Details below the Image Accuracy Indicator. The report includes average measurement accuracy on the ortho-photo (in meters), the digitizing accuracy in pixels, and the residuals on the image. Q: The ortho-photo looks OK, but the Image Accuracy Indicator is not Green; what is the problem and what should I do? You either did not precisely pinpoint one of more of the reference anchor points, or one or more of your anchor points do not lie exactly on the ortho-photo datum plane. You can check which point is problematic by accessing the detailed quality report. The problematic point(s) will have relatively large residuals, indicated in yellow or even red. Compare these points to the field sketch, and correct their position. - 39 -
7 Generating Reports To generate a report in PDF format: 1. In the Report screen, click the plane for which you wish to generate a report, and select Report. The report includes the information about the job and plane, detailed information on the measurement accuracy quality, and a list and summary of all the layers you have drawn on the ortho-photo. : - 40 -
About Datumate Datumate is a leading vendor of geodetic expert systems. Datumate software products, combining technological innovation and geodetic expertise, support land surveyors worldwide by improving productivity of field personnel, quality control and management of surveying project. Among Datumate s customers are the Survey of Israel, Israel s national mapping agency, as well as numerous leading land surveying firms worldwide. To learn more see: www.datumate.com - 41 -