A way of encoding raster data that reduces storage requirements by creating linear groups of identical pixels rather than storing the values of each pixel individually.

A data compression technique for storing raster or gridded data. Run-length encoding stores data by row. If two or more adjacent cells in a row have the same value, the 'run' is recorded, as opposed to recording an individual value for each cell. The more adjacent columns having the same value, the greater the compression.

Run-length encoding (RLE) is a very simple form of data compression in which runs of data (that is, sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count, rather than as the original run. This is most useful on data that contains many such runs: for example, simple graphic images such as icons and line drawings.