Thursday, December 3, 2015

Output formatting

GIS output is in the form of:

  1. Maps
  2. Charts

  1. Charts can be used to display tabular data
  2. Types of charts available are generally of six types. They are:
    1. Area chart
    2. Bar chart
    3. Line chart
    4. Column chart
    5. Pie chart and
    6. Scatter chart
A map is a spatial model of the real world and is differentiated from it (the real world) due to:
  • Abstraction 
    • Imaginary & physical features
    • Past, Present and future features
  • Focus
    • Selection and classification of features to be included in map
  • Simplification
    • Simplification of complex features 
    • Exaggeration of small features
  • Symbolization
    • Using symbols to represent objects
  • Scale
    • Ratio of distance on map to distance on Earth
  • Projection
    • Representing curved Earth on a flat plane
  • Purpose 
    • To describe, measure, communicate/persuade.
Types of maps 
  1. Planimetric
  2. Topographic
  3. Cadastral
  4. Image
  5. Thematic
Below listed are a few general principles to create maps:
  1. Output maps (GIS output) should be kept simple to understand and not cluttered with too much information by relying excessively on software defaults
  2. Only the area under study should be included along with a small map inserted showing the relative location.
  3. The maps should be created keeping in mind the final publication sale. This implies a size reduction for report or journal publication. It should be borne in mind that point symbols reduce in visibility at twice the rate of line features.
  4. The title should be mentioned at the top in thick line font: serif/sans-serif; case not critical
  5. Map labels should be formatted as per the following guidelines:
    • labels should be in serif font (first letter uppercase and remaining lowercase)
    • labels should be placed above and to the right of the feature (2nd choice: above and to the left)
    • Font size hierarchy should indicate relative importance
    • Water features traditionally labeled in italic font
  6. The map should be created in black and white and the colour should be added later
Hue refers to the actual colour; Saturation refers to the amount of the colour, while value refers to the amount of black used.
For optimum readability, low saturation in the background and high saturation in the foreground is recommended.

Choice of shading
In case of:
  • Quantitative data:
    • Symbols should have visual progression corresponding to data values
    • For polygons, using monochromatic colour ramp: same colour, different saturation
      • can highlight top and bottom with contrasting colour
      • "visual progression" should be ensured if different fill patterns are used
    • For point symbols, different sizes of the same symbol must be used.
  • Qualitative data:
    • For polygons, different fill colours or different patterns should be used
    • For point symbols, same size of different symbols should be used
  • The legend should be big enough to clearly show different fill patterns