Category: Processing and quality
Reprojection
Reprojection converts data from one coordinate reference system (CRS) to another.
Also known as: project, CRS transform
Expanded definition
Reprojection is the process of transforming coordinates so datasets in different CRS align correctly.
Reprojection often triggers resampling for rasters. That can introduce small shifts and smoothing, so it should be done in a controlled way.
A common operational pattern is to store data in a standard CRS for interchange (often WGS84) and reproject into a local projected CRS (often UTM) for measurement and analysis in meters.
Related terms
CRS (Coordinate Reference System)
A CRS defines how coordinates map to locations on Earth, including the projection and datum.
EPSG Code
An EPSG code is a numeric identifier for a CRS, such as EPSG:4326 for WGS84 latitude/longitude.
UTM (Universal Transverse Mercator)
UTM is a projected coordinate system that divides Earth into zones, allowing measurements in meters.
Resampling
Resampling changes the pixel grid of a raster, for example when reprojecting or changing resolution.