Understanding Image Formats

If you open a drawing containing an image format that is not supported, AutoCAD Raster Design toolset does not load the image. If you attempt to insert an image that uses an unsupported format, you are warned that the format is not supported.

Similarly, if you select several files and select the Treat As Multispectral option, AutoCAD Raster Design toolset checks whether the files share the same coordinate system, projection, color depth, extents, and units. If these criteria are not met, the files cannot be used as a multispectral dataset. However, they may be displayable individually, and you may be able to edit them to resolve the differences.

If you insert a read-only image into your drawing, you can configure a color map for it and save it in a drawing. You can use the Raster menuCapture command to save a displayable image for use in other applications. If you want to edit the image, you can use the Raster menuSave As command to save the image to a read-write format before or after you edit it.

AutoCAD Raster Design toolset can read and write world files for any image type. World files contain correlation information for images, such as scale, rotation, and insertion point.

AutoCAD Raster Design toolset can write or save images in 1-, 8-, 16-, 24-, or 32-bit format, but it can read more image formats than it can write. The following table provides details about how the various formats are supported:
Format File extension Description Read (bits per pixel) Write (bits per pixel)
BMP BMP, RLE, DIB Windows Bitmap 1, 8, 24, 32 1, 8, 32
CALS CAL, GP4, RST, MIL, CG4 Computer-Aided Acquisition and Logistics Support 1 1
DEM DEM Digital Elevation Model 32 32
DOQ DOQ, NWS, NES, SES, SWS Digital Orthophoto Quadrangle 8, 24 read only
DTED DT0, DT1, DT2 Digital Terrain Elevation Data 16, 32 read only
ECW ECW Enhanced Compressed Wavelet 8, 24, 32 read only
ESRI ASCII Grid ASC ESRI interchange format 16 read only
ESRI Binary Grid ADF ESRI internal format 16 read only
FLIC FLC, FLI Animator FLIC 8 read only
GeoSPOT BIL SPOT Image Corporation’s raster format with georeferencing format 8, 24 read only
GeoTIFF TIF, TIFF Geo-referenced TIFF 1, 4, 8, 16, 24, 32 1, 8, 16, 32
GIF GIF Compuserve® Graphics Interchange Format 8 read only
IG4 IG4 Image Systems Group 4 1 read only
JFIF- JPEG JPG Joint Photographics Expert Group, best suited for 24-bit images 8, 24, 32 8, 24
JPG2000 JP2, J2K JPEG 2000 8, 24 8, 24
Landsat FAST-L7A FST Multispectral format used by Landsat 7, primarily for multiframe image sets. 8 read only
MrSID SID Multiresolution Seamless Image Database 8, 24, 32 read only
NITF NTF National Imaging Transmission Format; can be multiframe multispectral 1, 8, 24, 32 read only
PCX PCX A simple run-length encoded format 1, 4, 8, 24 1, 8
PICT PCT, PICT Apple® Computer format 8, 24, 32 read only
PNG PNG Portable Network Graphics 1, 4, 8, 24, 32 1, 8, 24, 32
PSD PSD Adobe Photoshop 8, 24, 32 read only
QuickBird TIFF TIF, TIFF Images from DigitalGlobe’s QuickBird satellite; typically multiframe, multispectral, but can also be single-frame panchromatic 8, 16 read only
RLC1 RLC Run-Length Coding with no header 1 read only
RLC2 RLC RLC with IST headers 1 read only
TARGA TGA Format developed by Truevision Inc. Usually 24-bit true color; can be 8-bit grayscale or simple run length encoded 8, 16, 24, 32 8, 32
TIFF TIF, TIFF Tagged Image File Format, developed by Aldus Corporation 1, 4, 8, 16, 24, 32 1, 8, 16, 32