# MEM -- In Memory datasets

Driver short name

MEM

Driver built-in by default

This driver is built-in by default

GDAL supports the ability to hold datasets 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.

This page documents its raster capabilities. Starting with GDAL 3.11, this driver has been unified with the long-time existing Memory driver to offer both raster and vector capabilities.

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,
         GEOTRANSFORM=1.166396e+02/1.861068e-05/0.000000e+00/3.627969e+01/0.000000e+00/-1.861068e-05

or

    MEM:::DATAPOINTER=0x1467BEF0,PIXELS=100,LINES=100,BANDS=3,DATATYPE=Byte,
         PIXELOFFSET=3,LINEOFFSET=300,BANDOFFSET=1,
         GEOTRANSFORM=1.166396e+02/1.861068e-05/0.000000e+00/3.627969e+01/0.000000e+00/-1.861068e-05

- 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.

- GEOTRANSFORM: Set the affine transformation coefficients. 6 real numbers with '/' as separator (optional)

- SPATIALREFERENCE: (GDAL >= 3.7) Set the projection. The coordinate reference systems that can be passed are anything supported by the OGRSpatialReference.SetFromUserInput() as per '-a_srs' in gdal_translate. If the passed string includes comma or double-quote characters (typically WKT), it should be surrounded by double-quote characters and the double-quote characters inside it should be escaped with anti-slash. e.g `SPATIALREFERENCE="GEOGCRS[\"WGS 84\",[... snip ...],ID[\"EPSG\",4326]]"`

Warning

Starting with GDAL 3.10, opening a MEM dataset using the above syntax is no longer enabled by default for security reasons. If you want to allow it, define the `GDAL_MEM_ENABLE_OPEN` configuration option to `YES`, or build GDAL with the `GDAL_MEM_ENABLE_OPEN` compilation definition.

GDAL_MEM_ENABLE_OPEN=[YES​/​NO]: (GDAL >= 3.10) Defaults to `NO`. Whether opening a MEM dataset with the `MEM:::` syntax is allowed.

## Creation Options

Creation options can be specified in command-line tools using the syntax `-co <NAME>=<VALUE>` or by providing the appropriate arguments to `GDALCreate()` (C) or `Driver.Create` (Python). This driver supports the following creation option:

- INTERLEAVE=[BAND​/​PIXEL]: Defaults to `BAND`. Set the interleaving to use

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.

## Driver capabilities

Supports CreateCopy()

This driver supports the `GDALDriver::CreateCopy()` operation

Supports Create()

This driver supports the `GDALDriver::Create()` operation

Supports Georeferencing

This driver supports georeferencing

## Multidimensional API support

Added in version 3.1.

The MEM driver supports the Multidimensional Raster Data Model.