Map Design and Symbology in GIS Environment
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This document discusses key principles of map design including selection of colors, symbols, labeling, and overall layout. It emphasizes that while there are scientific rules of map design, there is also an artistic element. The document outlines topics to be covered such as map scale and generalization, symbolization, choropleth mapping, use of color, and labeling. It provides guidelines for map elements like titles, legends, and orientation indicators. It also discusses classification schemes, issues with choropleth maps, effective use of color, and best practices for labeling and typography. Ethical practices of map design to avoid deception are highlighted.
Map Design and Symbology in GIS Environment
- 1. Asib Ahmed (asib01geo@du.ac.bd) Lecture 1, Wednessday 16th April 2014
- 2. There are some (scientific) rules in map design but much artistic judgement in terms of ◦selection of colours ◦symbology ◦labelling (format and position) ◦arrangement of overall layout ◦(plus data selection, projection, scale, etc) Subtle changes in design (e.g. weight of a label font for particular objects) can yield big changes in how the map is read Use (and mis-use) the power of design. ethical practices not to deliberately deceive
- 3. 1. Classification 2. simplification 3. symbolization
- 4. 1.Map layout 2.Map scale and generalisation 3.Symbolisation and graphic variables 4.Choropleth mapping & data classification 5.Colour 6.Labelling and typography
- 5. For presentation of maps, some conventions on what to include: ◦a title (or caption). clearly state what the map shows. plus relevant date of data, sources, missing values, author, contact info, etc ◦a legend, so any reader can interpret the content of the map. meaning of all symbol and colours ◦scale indication. translates distance on the map to distance on the ground ◦orientation indication (the good old north arrow) ◦borders and neatlines
- 6. 1 1.618
- 8. what level of detail is shown crucial to choose appropriate scale to work at large scale map : small surface area in high detail (e.g. city plans) small scale : large surface area in low detail (e.g. national road atlas) scale represented as a statement (“one inch equals five miles”), a graphical scale bar, (useful for measuring lengths), or as a representative fraction (1:1250) very few maps use scale consistently for every object
- 9. Key modes of generalisation • distortion is inherent, inevitable, unavoidable •may have to leave features off the map altogether • avoid visual clutter, balance content and legibility
- 10. graphic language (of points, lines, polygon, icons and text) used to represent ‘real’ features on the map legibility (‘practical’) harmonious (‘pretty’) symbols can be iconic, geometric or abstract symbol selection is creative aspect of design, wide choice and few firm rules symbols can have several different dimensions (properties or characteristics) which encode meaning symbols can have quantitative or qualitative meaning
- 11. shape, size, orientation colour hue, colour value, colour saturation, pattern and location of course
- 12. (Source: Larry Landweber, http://www.cs.wisc.edu/~lhl/maps/)
- 13. choro from choros (place) and pleth (value) counterpart of histogram aggregate data, usually ratio or percentage data map for discrete spatial units practical Issues ◦choice of intervals - number and their breaks ◦equal interval, equal share (quantiles), standard deviational, … choice of colors ◦important for perception of patterns misleading role of area of spatial units ◦larger areas “seem” more important
- 14. classification is a key method of abstracting reality into simplified map method of classification is important as effects ‘look’ of the map classification scheme can easily be experimented with (manipulated?) to give the pattern you want classification should ‘match’ data distribution number of classes. can reader interpret between them? recommended max of 6 distribution of zones into classes
- 15. Same data plus different classification equal different looking choropleth map!
- 16. •natural breaks (Jenks method) •quantiles •equal interval •standard deviation
- 20. colour is one of most exciting aspects of design colour perception is a combination of physiological (sensing in the eye and cognitive processing) and psychological reactions colour evoke emotions. subjective reaction to colour connotative meanings of colour. See Dent (1999, page 295)
- 21. cultural specific. also colour blindness. 7% of men and 1% of women warm colours (red, orange, yellows) cool colours (violet, blue, greens defining - hue, saturation, value (HSV) model
- 22. hue - basic colour we perceive, eg 12 step Wheel saturation - intensity or purity compared to a neutral gray value - lightness or darkness. Can be hard to perceive variations in value
- 24. gives structure and readability developing figure and ground relationships ◦warm colour better for figures. Said to ‘advance’ to viewer. Cool colours tend to recede perceptual grouping of like features through colour colour contrasts. using value or saturation to represent data on thematic maps qualitative conventions - blue for water, green for lush vegetation; red = warm and blue = cool in temperatures; hill shading
- 25. lettering choice can have a significant impact to effectiveness of the map map text to label features has several key parameters ◦font typeface, size spacing ◦placement and orientation importance of type discernibility map labels can communicate important data, e.g. hierarchy of features, implying importance Chislehurst, Bromley, L O N D O N manual labelling of features can get very tedious. but automatic label placement is still far from perfect
- 26. Think about different types of lettering styles and placement/orientations used and the effects it has
- 27. ◦legibility of individual letters is of paramount importance, especially in smaller type sizes. Choose a typeface in where there is little chance of confusion between c and e and i and j ◦select a typeface with a relatively large base height ◦avoid extremely bold forms ◦choose a typeface that has softer shading; extreme vertical shading is more difficult to read than rounder forms ◦do not use decorative typefaces on the map as they are difficult to read
- 28. 1. always have a straightforward agenda, and have a defining purpose or goal for each map 2. always strive to know your audience, the potential/likely map users 3. do not intentionally lie with data 4. always show relevant data whenever possible 5. data should not be discarded simply because they are contrary to the position held by the cartographer 6. at a given scale, strive for an accurate portrayal of the data
- 29. 7. the cartographer should avoid plagiarizing; report all data sources 8. symbolization should not be selected to bias the interpretation of the map 9. the mapped result should be able to be repeated by other cartographers 10. attention should be given to differing cultural values and principles
- 30. ◦Borden Dent, (1995) Cartography: Thematic Map Design, fifth edition ◦Terry Slocum, (1999) Thematic Cartography and Visualization ◦Menno-Jan Kraak and Ferjan Ormeling, (1996) Cartography: Visualization of Spatial Data