Supported raster data
Raster formats
ArcPad supports the following raster image formats:
- Graphic Interchange Format, or GIF (*.gif)
- JPEG (*.jpg)
- JPEG 2000 (*.jp2)
- MrSID Generation Two, or MG2 (*.sid)
- MrSID Generation Three, or MG3 (*.sid)
- Portable Network Graphics, or PNG (*.png)
- Tagged Image File Format, or TIFF, including GeoTIFF (*.tif)
- Windows Bitmap (*.bmp)
- CADRG raster maps
The supported compression methods for GeoTIFF are the following:
- Uncompressed
- LZW
- CCITT T.3 Huffman RLE 1D
- CCITT T.4 Fax Group 3
- CCITT T.6 Fax Group 4
- Deflate
- Packbits
Additional raster data formats can be supported via ArcPad extensions.
Georeferencing information
Raster files must have associated georeferencing information. This georeferencing information includes the size of the pixels, as well as the coordinate position of the reference pixel.
The georeferencing information can be stored in three locations:
- Within the header section of the image, such as with GeoTIFF or MrSID images.
- Within an associated Auxilliary (.aux) file, such as created by ArcGIS.
- Within an associated world file.
All raster files must have either a world file or an AUX file, with the exception of GeoTIFF and MrSID images.
When adding a raster layer to an ArcPad map, ArcPad first looks in the image header for the georeferencing information, then in the associated .aux file (if present), then within an associated world file (if present).
The Add Layers dialog box only displays raster files that have an associated world or AUX file. The Add Layers dialog box does not check the contents of the world or AUX file for valid data; it simply checks for the existence of these files to determine whether the raster file is supported by ArcPad. The exception to this rule are GeoTIFF and MrSID images, which do not need to have associated world or AUX files.
The naming convention for world files is to use the first and third characters of the image file’s suffix and a final “w” for the world file suffix. For example:
- *.jgw for JPEG images (*.jpg)
- *.j2w for JPEG 2000 images (*.jp2)
- *.sdw for MrSID images (*.sid)
- *.tfw for TIFF images (*.tif)
- *.bpw for Windows Bitmap images (*.bmp)
Projection information
Raster files must also have associated projection information. This projection information enables ArcPad to correctly position the image on a map with a defined projection, or coordinate system.
The projection information can be stored in three locations:
- Within the header section of the image, such as with GeoTIFF images.
- Within an associated Auxilliary (.aux) file, such as created by ArcGIS.
- Within an associated map projection file (*.prj).