Raster Dataset Pixel Format

In SuperMap, raster data consists of two types: raster dataset (GRID) and image dataset (IMAGE). The former is primarily used for raster analysis, while the latter is mainly for display or as map layers. To accommodate the complex representations of raster datasets, SuperMap provides multiple pixel formats, allowing users to select the appropriate format based on specific workflow requirements.

Pixel Formats for Raster Datasets

Pixel Format Format Description
1-bit   Value range [0, 1]. No-value defaults to 0, but may default to 1 or -9999 in certain scenarios.
4-bit Bit Value range [0, 15]. No-value defaults to 0, but may default to 1 or -9999 in certain scenarios.
8-bit (single byte) Byte Value range [0, 255]. No-value defaults to 0, but may default to 1 or -9999 in certain scenarios.
16-bit (double byte) TByte Value range [-2e+15, 2e+15-1]. No-value defaults to -9999.
24-bit (triple byte)   Value range [-2e+23, 2e+23-1]. No-value defaults to -9999.
32-bit (integer) Int Value range [-2e+31, 2e+31-1]. No-value defaults to -9999.
64-bit (long integer) Long Value range [-2e+63, 2e+63-1]. No-value defaults to -9999.
Single Float Value range [-2e+31, 2e+31-1]. No-value defaults to -9999.
Double Double Value range [-2e+64, 2e+64-1]. No-value defaults to -9999.

Pixel Formats for Image Datasets

Pixel Format Format Description
Monochrome   Represents two colors: black and white.
16-color Bit Represents 16 indexed colors, which can be defined in the color table.
256-color Byte Represents 256 indexed gradient colors, which can be defined in the color table.
Color TByte Each pixel uses 16 bits: 5 bits each for red, green, and blue, with 1 bit unused.
True Color RGB Each pixel uses 24 bits: 8 bits each for red, green, and blue.
Enhanced True Color RGBA Each pixel uses 32 bits: 8 bits each for red, green, blue, and alpha. Does not support multi-band images.