rastertype

Rastertype is a term used in geospatial data processing to describe the data type and storage characteristics of raster data. It specifies how pixel values are encoded, including the number of bits per sample and whether the values are integers or floating-point numbers. Typical raster types include 8-bit unsigned integers (Byte), 16-bit signed or unsigned integers (Int16, UInt16), 32-bit integers (Int32, UInt32), and floating-point types (Float32, Float64).

Rasters may be single-band or multi-band, with each band potentially having its own rastertype. In many formats, the rastertype is critical for determining the dynamic range, precision, and memory requirements. It also affects which arithmetic and statistical operations are valid and how no-data values are handled.

Management and processing considerations include casting or resampling rastertypes to a common type to avoid overflow or underflow and to optimize performance. Quantization errors can occur when converting higher-precision data to lower-precision types, and some operations may introduce or propagate such errors. Storage optimization, such as compression or bit-depth packing, can influence allowable types and performance.

Rastertype is related to, but distinct from, the raster file format (for example GeoTIFF, HDF5, NetCDF) and from color models or band layouts. Formats define storage layout and metadata, while rastertype defines the numerical representation of pixel values. Understanding rastertype is important for data compatibility, accuracy, and the reproducibility of geospatial analyses.