Cartographic Design Principles for GIS

Three processes common to all maps:

1. Reduction (scale) National Map Accuracy Standards: on maps < 1:20,000, 90% of all locations must be within 0.02" (0.5 mm) of actual location.
2. Selection
3. Symbolization

Important Map Elements (borrowed from Hugh):

1. Title & subtitle
2. Legend (note: for choropleth maps, do not have overlapping values) For classification of interval/ratio data, leave no gaps between boxes, for nominal variables, leave gaps. For site suitability, numbers are subjective -- needs clarification in explanatory text -- use MOVE then TEXTFILE to place text from a text file you've created.
3. Sources/Credits
4. Scale
5. Direction (North arrow not critical for north oriented)
6. Coordinate system, including grid reference
7. Graphic Primitives: margin/framelines, logos, boxes/lines, etc.
8. Insets (detail, reference) : use maplimits to define new area to work in, set new scale, etc.
9. Typography: recommend nicer (zipcode) fonts. Some cartographic conventions: italics for water bodies/streams, perhaps in blue textcolor
10. Symbology : For choropleth maps, increasing darkness (decreasing color value) with increasing numeric value. (Keep same hue & chroma, or use a color ramp (see SHADECOLORRAMP, for example)

Do not consider the above as a checklist for what must be on a map, but perhaps a checklist for what to consider.

Communication Concepts

• reader "flow" through the map
• consideration of purpose & audience
• figure to ground
• clarity & legibility (e.g. consider size of text and other symbols for size of map output)

Other considerations for the suitability map:

• pagesize: no more than 21" wide, 17" high
• explanatory text: explain the suitability index -- what it's based on.