Raster
Overview
Raster is a type of spatial data in a GIS that represents geographic features as a grid of cells or pixels, each with a specific value, often used for continuous data such as elevation, temperature, or satellite imagery. Raster data excels at representing phenomena that vary continuously across space.
Key Concepts
Cell/Pixel is the individual unit of a raster grid. Resolution is the ground size of each cell (e.g., 10m, 30m). Band is a single layer of values (multispectral images have many bands). Extent is the geographic area covered by the raster. NoData is a value indicating missing or invalid data. Bit depth is the range of possible values per cell.
Raster Types
| Type | Description | Examples |
|---|---|---|
| Continuous | Smooth gradation of values | Elevation, temperature |
| Discrete | Categorical values | Land cover, soil type |
| Imagery | Reflectance/brightness | Satellite, aerial photos |
| Derived | Computed from other rasters | Slope, aspect, hillshade |
Common Formats
Appendix
Created: 2025-12-13 | Modified: 2025-12-13
See Also
- Vector
- Pixel
- Resolution
- Geographic Information System (GIS)
- Geospatial Data Abstraction Library (GDAL)