Symbology
Overview
Symbology is the visual representation of spatial features in a GIS, including the use of colors, symbols, and styles to convey information about the data. Effective symbology communicates geographic patterns clearly and enables users to interpret spatial data at a glance.
Key Concepts
Symbol is a graphic element (marker, line, fill) representing a feature. Color ramp is a gradient of colors representing a range of values. Classification groups features into categories for distinct symbols. Transparency/Opacity controls how much underlying features show through. Labeling displays text annotations from feature attributes. Legend explains the meaning of symbols on a map.
Symbology Types
| Type | Description | Use Case |
|---|---|---|
| Single symbol | Same symbol for all features | Simple reference maps |
| Unique values | Different symbol per category | Land use, zoning |
| Graduated colors | Color ramp by numeric value | Population density |
| Graduated symbols | Size by numeric value | City populations |
| Heat map | Density visualization | Event clusters |
Appendix
Created: 2025-12-13 | Modified: 2025-12-13