# MEM -- In Memory Raster

GDAL supports the ability to hold rasters in a temporary in-memory format. This is primarily useful for temporary datasets in scripts or internal to applications. It is not generally of any use to application end-users.

Memory datasets should support for most kinds of auxiliary information including metadata, coordinate systems, georeferencing, GCPs, color interpretation, nodata, color tables and all pixel data types.

## Dataset Name Format

It is possible to open an existing array in memory. To do so, construct a dataset name with the following format:

      MEM:::option=value[,option=value...]

For example:

      MEM:::DATAPOINTER=342343408,PIXELS=100,LINES=100,BANDS=3,DATATYPE=Byte,
           PIXELOFFSET=3,LINEOFFSET=300,BANDOFFSET=1

or

      MEM:::DATAPOINTER=0x1467BEF0,PIXELS=100,LINES=100,BANDS=3,DATATYPE=Byte,
           PIXELOFFSET=3,LINEOFFSET=300,BANDOFFSET=1

- DATAPOINTER: address of the first pixel of the first band. The address can be represented as a hexadecimal or decimal value. Hexadecimal values must be prefixed with '0x'. Some implementations (notably Windows) doesn't print hexadecimal pointer values with a leading '0x', so the prefix must be added. You can use CPLPrintPointer to create a string with format suitable for use as a DATAPOINTER.
- PIXELS: Width of raster in pixels. (required)
- LINES: Height of raster in lines. (required)
- BANDS: Number of bands, defaults to 1. (optional)
- DATATYPE: Name of the data type, as returned by GDALGetDataTypeName() (eg. Byte, Int16) Defaults to Byte. (optional)
- PIXELOFFSET: Offset in bytes between the start of one pixel and the next on the same scanline. (optional)
- LINEOFFSET: Offset in bytes between the start of one scanline and the next. (optional)
- BANDOFFSET: Offset in bytes between the start of one bands data and the next.

## Creation Options

There are no supported creation options.

The MEM format is one of the few that supports the AddBand() method. The AddBand() method supports DATAPOINTER, PIXELOFFSET and LINEOFFSET options to reference an existing memory array.