This topic provides an overview of spatial data, including types of spatial data, sources of spatial data, and the importance of spatial data in various fields such as geography, environmental science, urban planning, and more.
Introduction to Spatial Data
Key concepts, data types, sources, and basic workflows
1. What Is Spatial Data?
| Term |
Definition |
| Spatial data (or geospatial data) |
Information that describes the location, shape, and relationship of objects on Earth (or any coordinate‑based space). |
| Attribute data |
Non‑spatial information linked to a spatial feature (e.g., population of a city, land‑use type). |
| Coordinate reference system (CRS) |
The mathematical framework that translates real‑world positions into numeric coordinates (e.g., latitude/longitude, UTM). |
Why it matters: Enables mapping, analysis of patterns, routing, environmental modeling, urban planning, disaster response, etc.
2. Core Data Models
| Model |
Geometry Type(s) |
Typical Use |
Storage Format |
| Vector |
Points, lines, polygons (and multi‑geometries) |
Discrete features – cities, roads, parcels |
Shapefile, GeoJSON, GPKG, KML, File Geodatabase |
| Raster |
Grid of cells (pixels) with a value per cell |
Continuous phenomena – elevation, temperature, satellite imagery |
GeoTIFF, IMG, NetCDF, HDF |
| TIN (Triangulated Irregular Network) |
Irregular triangles |
Surface modeling where data are unevenly spaced (e.g., LiDAR) |
.tin, GPKG (vector) |
| Network |
Nodes + edges with connectivity rules |
Transportation, utility networks |
ESRI Network Dataset, pgRouting tables |
3. Common Spatial Data Formats
| Category |
Format |
Strengths |
Limitations |
| Vector |
Shapefile (.shp) |
Widely supported, simple |
1‑GB size limit, limited attribute length, separate files |
|
GeoJSON (.geojson) |
Web‑friendly, human‑readable |
Larger file size than binary equivalents |
|
GeoPackage (.gpkg) |
Single‑file, supports raster & vector, SQLite‑based |
Newer; some legacy tools lack full support |
| Raster |
GeoTIFF (.tif) |
Embedded CRS, lossless compression options |
Large files for high‑resolution data |
|
NetCDF (.nc) |
Multidimensional scientific data, metadata rich |
Complex; requires specialized libraries |
| Imagery |
JPEG2000, ECW |
High compression ratios |
Proprietary licensing (ECW) |
| Web Services |
WMS, WMTS, WFS, WCS |
On‑demand data delivery, standards‑based |
Dependent on internet connectivity and server performance |
4. Sources of Spatial Data
| Source |
Description |
Typical Access Method |
| Government agencies (e.g., USGS, INSPIRE, NGA) |
Topographic maps, cadastral parcels, elevation models |
Download portals, APIs |
| Open data portals (OpenStreetMap, Natural Earth) |
Crowd‑sourced or curated global datasets |
OSM API, vector tiles, bulk extracts |
| Commercial providers (e.g., DigitalGlobe, HERE) |
High‑resolution satellite imagery, traffic data |
Subscription, cloud storage |
| Sensor networks (LiDAR, UAV, IoT) |
Point clouds, real‑time environmental readings |
Direct file transfer, streaming APIs |
| Scientific repositories (Copernicus, NASA) |
Climate, ocean, atmospheric data |
FTP, O |