Cartography FieldCarto_Handoff.indb 1 4/27/18 9:31 PM

Transcription

1 Cartography FieldCarto_Handoff.indb 1

2 Abstraction and signage All maps are the result of abstraction and the use of signage to represent phenomena. Because the world around us is a complex one, it would be virtually impossible to simply place a small version of it on a map. There would not be the space to adequately represent all features that exist in the mapped area even in a reduced form. Consequently, all maps are abstractions of reality and are used to display a selection of objects and attributes. All maps are inherently a reduction of reality and so the amount of information you can put on a map will be a reduced form of that reality. This means a map will omit information to a greater or lesser extent depending on scale and purpose. But more than reduction (through selective omission), the features that are mapped are subject to a range of additional processes, such as classification and simplification, that make it easier to understand the true spatial patterns and relationships that exist in reality. The way in which we represent features and their attributes is through the design and placement of graphical signs. These signs do not necessarily take on the appearance of the object in reality but are used to represent the object. The signs should have meaning to enable the map reader to interpret them accurately and appropriately relate them to the realworld object. We refer to the process of encoding meaning into the map as symbolisation. At its simplest level, part of the job of the mapmaker is to design and place symbols that reflect either location or some characteristic of the data. There is considerable scope in the design of symbols and every mark on a map can be considered a symbol in one form or another, from those that represent points, lines, and areas to the typographic components and the marginalia or contextual information. Whereas the principal task of map design is in the decisions taken to select, omit, and symbolise phenomena, there are many processes at work that are difficult to accommodate. For instance, induction occurs when the mapmaker builds signage that depends on some level of inference between mapped features. In this sense, they are applying inductive generalisation to extend the map s content without physically adding more symbols. The use of contour lines is a good example of the process of induction since, depending on the distance between contour lines and whether they get progressively closer or more distant, inference is made about the nature of the landscape. A concave ridge will be flatter toward the summit and steeper toward its base. Contours will be closer together at the base and further apart at the summit to represent and infer this. Although certain inferences might be imbued into the map by the mapmaker, the map reader will inevitably play a role in interpretation. Someone with a good sense of map use and reading might find it easy to see and understand such inferences but, for others, the inferences may be harder to see. For this reason it is best to avoid inductive generalisation where possible and, instead, solve your communication dilemmas through good, clean design with more obvious visual cues. Clarity and purpose follow from a careful consideration of abstraction and signage. Beyond the science of choosing and representing the information, the sophistication of the intended audience, scale, and conditions of use must also be considered so you end up with a clear and concise map that your map reader can easily translate into meaning. See also: Dynamic visual variables Literal comparisons Pictograms Varying symbols 2 Cartography. FieldCarto_Handoff.indb 2

3 Abstraction and signage 3 FieldCarto_Handoff.indb 3

4 Additive and subtractive colour Mapping for screen or print demands a different approach to colour specification. Map colours are specified by mixing additive or subtractive colours. For screens, additive colours red, green, and blue (RGB) are mixed. For print, subtractive colours of cyan, magenta, and yellow (CMY) are mixed. These two systems are not perfectly interchangeable since purity of light is not matched by printing ink. For instance, you cannot mix the very vivid colours made possible on a computer display by using CMY inks on a page. Printing very light colours is also difficult because spacing small ink dots so far apart does not generate smooth colours. Additive colour mixing is used for devices that normally have a black background representing no colour transmission. The opposite is true for printed maps in which you instead perceive reflected light. Light that illuminates paper passes through the printing ink and is reflected back off the paper. The reflected colour is the colour of the ink. If several layers of ink are overprinted on each other, reflected light is absorbed differently by each layer of ink so the result is a mix of the layers. If you use transparent ink in the three primary colours, light will be absorbed by them and, in theory, no light will pass through any combination of the colours resulting in a black image (i.e. no reflection). Printing on paper uses subtractive colour mixing and transparent inks in cyan, magenta, and yellow. Cyan transmits green and blue, magenta transmits red and blue, and yellow transmits red and green. For example, if yellow ink is printed on top of cyan ink on white paper, the yellow ink absorbs blue light but transmits red and green; the cyan layer then absorbs red light so only the green light reaches the paper and is reflected back to the observer. CMY colours are also referred to as process colours. Black (K) is usually used as a fourth printing ink to create pure black text and line work and better printed greys. The K means key in four-colour process printing since black is normally printed first and other colours are keyed or registered to it. These pigments are also used in ink and laser printers, which apply percentage coverage of tiny dots to the paper. Colour is seen through the stimulation of different cones in our eyeballs. For three beams of overlapping red, green, and blue light, all three types of cones are stimulated simultaneously and this creates the perception of white light. Where only two beams overlap, the transmitted light produces a mix of colour that is formed by the stimulation of pairs of cones. Blue and green together form cyan, blue and red form magenta, and red and green produce yellow. By altering the intensity of each of the beams of light, different colours can be created. On maps, thin linework in colours other than black is often required. For instance, pale blue for rivers and brown contour lines are not easily created. Brown lines can be created by overprinting pale tints of all three process colours. However, registering thin lines on top of each other is often beyond technical limits of the printing process, leading to lines that are blurred. Furthermore, each line is composed of small dots of each of the process colours so this in itself renders a line that can never be sharp. Because of these problems, printers can premix inks for certain colours. Premixed colours are called spot colours and, in fact, most national mapping agencies print topographic maps using spot colours or a mix of four-colour and a few spot colours. Spot colours can also be printed in percentage tints so open water can be a percentage tint of a blue spot colour. Printing ink manufacturers produce a range of spot colours. One such system, Pantone, produce spot colours by mixing two or three of a basic set of nine colours plus pure black or white in predetermined proportions. Pantone provide a worldwide standard for colour specification, and if a map is sent for printing with a colour specification that identifies a particular colour as a Pantone colour, the printer will be able to match it. See also: Elements of colour Mixing colours Printing fundamentals Transparency 4 Cartography. FieldCarto_Handoff.indb 4

5 PANTONE 306 C PANTONE Rhodamine Red C PANTONE 107 C PANTONE Neutral Black C A D D I T I V E S U B T R A C T I V E PANTONE 485 C PANTONE 360 C PANTONE 7455 C Additive and subtractive colour 5 FieldCarto_Handoff.indb 5

6 Advertising maps The use of maps to sell. Considering people s general liking for, and trust of, maps, it s no surprise they re used heavily in advertising. Advertising is designed to create a clear image in a consumer s mind. It does so by being as appealing as possible. Cartographically, the aim is definitely form over function as it attempts to create a favourable comparison to a competitor s product, to emphasise a clear corporate image or to build trust, affinity, and demand for a product. Advertising might be used to show where something exists but omission and exaggeration are often used to build a picture. Graphic clarity is often replaced by the need to convince someone to buy. Maps in advertising often play on a theme. Maps might be used to show convenience or the spatial ubiquity of a service. Conversely they might highlight exclusivity. Maps are used to exploit the consumer, and the map itself is often exploited as a framework for selling some partial version of the truth. For instance, distances are sometimes warped to show places as being nearer or more convenient. Coverage is sometimes shown to be more than it actually is. So the map is used to present a highly generalised version of reality that can communicate the message immediately. Thus, the mapmaker often applies a large dose of artistic licence to exaggerate what they want to show and is creative in masking what they don t. Maps used in advertising tend to be some of the most inventive and pictorial. They often use very familiar shapes such as the outline of the world or of a country which are potent and recognisable symbols in their own right. They play to the fact that the consumer is already familiar with the basic structure of the graphic so the extent to which the image can be modified, yet still retain familiarity, is much greater than for maps that support other purposes. See also: Branding Copyright Emotional response Thematic maps Perhaps the map that is used to advertise more than most is the one that many people wouldn t even realise is being used in that way. Google Maps is the go-to map for millions of people each day. Most will use it for general-purpose tasks such as finding a location or seeking directions but Google did not produce the map as an act of philanthropy thinking that the world needed one consistent map for anyone to use. There is money to be made from maps, and Google itself is neither a map nor a search engine. Although its business has proliferated into a range of markets, at its core it s an advertising company whose revenue streams are predominantly from the money it makes by putting adverts in front of consumers. Google rapidly realised that the map can act as a proxy for an advertising hoarding. Every time we use the search engine on the map we re looking not only at the map but at the content that is being added. Over time, this content has gradually changed to support more advanced approaches. The map places you at the centre and builds content around you. If you search for a restaurant you are going to see those that Google promotes (because it is paid to do so) or which relate more to you to encourage you to go there. The same is true for a vast range of goods and services that take you to other websites, which may have content on them that Google gets paid to show. Opposite: Mockup of an advert for cellphone and data coverage. The ad wants you to believe in the extent of availability of the product. The map uses perspective, tilt, curvature and occlusion coupled with the symbology to relay that message. Simple to process and suggesting totality, the prism heights are unexplained and even bleed off the page and obscure text to infer it s too much to even show! The words reinforce the idea of coast-to-coast coverage with no gaps (despite the reality). The small legend acts as a disclaimer that is positioned to ignore. 6 Cartography. FieldCarto_Handoff.indb 6