Layer
Overview
Layer is a collection of spatial data in a GIS that represents a specific type of feature or theme, such as roads, land use, or elevation, often organized in a way that allows for easy visualization and analysis. Layers can be stacked and combined to create complex maps and enable spatial analysis.
Key Concepts
Base layer is the foundational layer (imagery, streets) upon which other layers are displayed. Overlay is a thematic layer displayed on top of base layers. Visibility controls whether a layer is displayed. Z-order determines the stacking order of layers. Transparency allows underlying layers to show through. Symbology defines how layer features are visually rendered.
Layer Types
| Type | Data Model | Examples |
|---|---|---|
| Vector | Points, lines, polygons | Roads, parcels, POIs |
| Raster | Grid cells | Imagery, elevation, land cover |
| Tile | Pre-rendered images | Basemaps, cached services |
| WMS/WFS | Web service | External data streams |
Appendix
Created: 2025-12-13 | Modified: 2025-12-13