Vektoridata

Vektoridata, or vector data, is a data representation used primarily in geographic information systems to model features as discrete geometries. Each feature is defined by a geometry, such as a point, line, or polygon, and by a set of attributes describing the feature. This approach contrasts with raster data, where information is stored as a grid of cells.

Geometries in vector data include points, multipoints, lines (line strings and multi-line strings), polygons (single and multi-polygons), and geometry collections. Coordinates are stored within a coordinate reference system, enabling accurate measurements and spatial relationships. Topology may be implicit or explicit, supporting operations like containment, intersection, and adjacency.

Formats and standards: A wide range of encodings exists, including Shapefile, GeoJSON, GML, KML, and GeoPackage. The Open Geospatial Consortium (OGC) develops standards such as Simple Features, which define the behavior and storage of vector geometries, and WKB/WKT representations for interchange.

Storage and management: Vector data can be stored in files or in spatial databases such as PostGIS or SpatiaLite. Spatial indexes, such as R-trees, improve querying and retrieval performance. Metadata and schema define the data model, including feature classes, attribute tables, and coordinate reference systems.

Applications and challenges: Vector data underpins cartography, routing, cadastral systems, environmental modeling, and urban planning. Advantages include precise boundary representation and efficient storage for sparse features, while challenges involve editing complexity, topology maintenance, versioning, and performance at very large scales.