Legend¶
A Map legend is a quick visual guide to understand the image of the map. As such it needs to explain the information being presented; the use of colour on the map, and any symbols or icons used.
In cartographic terms the Legend is used to describe the map (i.e. “Map Menu”) and as a summary of the colours and icons used (i.e. “symbology”).
Colour and Icons Used (Symbology)¶
For Layers that produce complex symbology further detail to explain the symbols will be needed:
- Continuous: When theming on a continuous value such as height often a smooth gradient of colour is used
- Categorisation: When categorising information into groups the groups will need to be listed and provided a unique colour and appearance
- Symbol Definition: When using distinct icons (or glyphs) to represent data points each shape will need to be listed along with a definition of what the symbol means. This can be relaxed when using a standard or well under known symbology set such as provided by MIL2525b or Emergency Response symbols for which the operator has been trainined.
Related reference