BMP (Windows and OS/2)

Long name Windows Bitmap
Short name BMP
File extension(s) .bmp

Windows and OS/2 BMP files are simple raster files. They are a common import and export format for applications under Windows and OS/2.

GDB supports the image variants that have 1, 4, 8, or 24 bits per pixel. GDB can read 4-bits per pixel BMP files but does not support the export of such files. BMP files must be uncompressed to be read by GDB. GDB will produce a 24-bit file if three channels are saved, an 8-bit file if one channel is saved, and a 1-bit file if a bitmap is saved. It is not legal to specify any other number of channels.

GDB will update any type of supported BMP file, but if asked to create a BMP file, it will create the Windows variant.


Export of Windows BMP files is supported. BMP files are exported with a type of "BMP".

Windows and OS/2 BMP files are supported for reading. However, only Windows BMP files can be exported. The user may specify 1 or 3 channels or 1 bitmap to be written to the BMP file. If one channel is selected, then a PCT may also be written.

© PCI Geomatics Enterprises, Inc.®, 2023. All rights reserved.