GISdatasets

GIS datasets are structured collections of geographic information used in geographic information systems to capture, store, manipulate, analyze, and present spatial data. They include spatial features such as points, lines, and polygons with attributes, or raster cells with values like elevation or imagery. Datasets are often organized into layers representing themes or feature classes and can be combined for analysis.

Common data types include vector datasets (points, lines, polygons), raster datasets (grids, imagery, digital elevation models), and tabular data that reference spatial features. Formats include Shapefile, GeoJSON, GeoPackage, GML, GeoTIFF for rasters, NetCDF, and HDF5. Metadata describes origin, accuracy, lineage, coordinate reference system (CRS), scale, and licensing, following standards such as ISO 19115 and FGDC.

Sources include government agencies, research institutions, NGOs, and citizen science projects, with licenses ranging from public domain to restrictive. Data quality considerations cover positional and thematic accuracy, completeness, resolution, and temporal relevance. The CRS and projections affect alignment across datasets, requiring coordinate transformations when integrating layers. Applications include mapping and visualization, environmental modeling, urban planning, transportation analysis, and disaster response. Datasets may be updated over time, necessitating versioning and provenance tracking. Access methods include local files, database-backed services, and web APIs, enabling GIS tools to query, analyze, and visualize geospatial information.