Geographic Information Systems (GIS)

The two fundamental approaches to representing geographic features in a GIS. Vector data uses discrete points, lines, and polygons with precise coordinate geometry, while raster data uses a continuous grid of cells (pixels) where each cell stores a value representing a phenomenon.

Mathematical frameworks that define how the curved surface of the Earth is projected onto a flat map or referenced in three-dimensional space. A CRS includes a datum (a model of the Earth's shape), a projection method, and coordinate units.

A set of techniques for examining the locations, attributes, and relationships of features in spatial data to extract meaningful patterns, detect clusters, measure distances, and model spatial processes.

A GIS operation that combines two or more spatial datasets by stacking them and performing logical or arithmetic operations (union, intersect, erase) to create new datasets that reveal relationships between layers.

Geocoding is the process of converting addresses or place names into geographic coordinates. Georeferencing is the process of aligning a non-spatial image (such as a scanned map) to a coordinate system so it can be used in a GIS.

The acquisition of information about the Earth's surface from sensors mounted on satellites, aircraft, or drones without direct physical contact. Remote sensing data, including multispectral and LiDAR, serves as a primary data source for GIS analysis.

Statistical methods that exploit the spatial correlation between observations to predict values at unmeasured locations. Techniques such as kriging, inverse distance weighting (IDW), and spline interpolation generate continuous surfaces from point samples.

A GIS capability that models connectivity and flow through linear features such as roads, pipelines, or rivers. It enables route optimization, service area analysis, and closest facility identification using graph theory principles.

Raster datasets that represent the continuous surface elevation of terrain. DEMs are used for slope analysis, watershed delineation, viewshed analysis, and 3D visualization. Common types include Digital Surface Models (DSM) and Digital Terrain Models (DTM).

The architecture and standards for publishing, discovering, and consuming geospatial data and maps over the internet. Web GIS uses standards like WMS, WFS, and REST APIs to serve interactive maps and spatial services to users through web browsers.