Vector data in Geographic Information Systems (GIS) is a type of spatial data representation that describes geographic features using discrete points, lines, and polygons. It is based on vector geometry, where features are represented as collections of coordinates (points) connected to form lines and polygons. Each point, line, or polygon in vector data is associated with attribute information, which provides additional details about the feature.
Key characteristics of vector data in GIS include:
- Points: Points are individual coordinates representing specific locations on the Earth’s surface. They are used to represent discrete features such as well locations, cities, or individual trees. Each point can have associated attribute data, such as the name of a city or the depth of a well.
- Lines: Lines are sequences of connected points that represent linear features in the landscape, such as roads, rivers, or pipelines. They have both length and direction and can be used to represent features with linear geometry.
- Polygons: Polygons are closed shapes formed by connecting a series of points. They are used to represent areas or regions on the Earth’s surface, such as land parcels, administrative boundaries, or lakes. Polygons have both an outer boundary and, in some cases, inner boundaries (holes).
- Attributes: Attributes are descriptive data associated with each point, line, or polygon feature. They provide information about the feature, such as its name, area, population, or any other relevant characteristics. Attributes allow users to query, analyze, and visualize the data.
Vector data is contrasted with raster data, another common data format in GIS. Raster data represents the Earth’s surface as a grid of cells, where each cell stores a single value or attribute. While vector data is well-suited for representing discrete features and complex geometries, raster data is used for continuous data and spatial analysis, such as elevation models, satellite imagery, and land cover classifications.
In GIS applications, vector data provides a versatile and precise means of representing and analyzing geographic features, making it essential for a wide range of spatial data management and analysis tasks.