Save Image Files with Georeferencing
When saving images that are considered Geographic Imager added formats, it will save reference information internally. Formats that contain internal reference, include: GeoTIFF, BigTIFF, DEM TIFF, GeoPackage, Geospatial PDF, ERDAS IMAGINE Raster, ECW, MrSID, and NITF. When working with any of these formats, use the Adobe Photoshop Save command to save the image and to update the reference file.
GeoTIFF is simply represented in the Adobe Photoshop Save As dialog box as TIFF (*.TIF, *.TIFF) and geospatial PDF is represented as Photoshop PDF (*.PDF, *.PDP). Depending on the originating image format, certain format types may not be available during save.
With the exception of PSD and PSB, when saving images to any Adobe Photoshop format, an external reference file will automatically be created. For example, when saving a georeferenced image to a non-geospatial format (e.g. JPEG), Geographic Imager creates an external reference file (e.g. World File). PSD and PSB will save reference information internally, as of Geographic Imager 6.4. To save to any of the supported image formats, use the Adobe Photoshop Save As command and choose the appropriate format in the Format drop-down list.
Saving spatial reference information to PSD and PSB does not apply to Photoshop cloud documents
During a Save As process, each supported format may have its own native Adobe options dialog box. For example, when saving as a GeoTIFF, the TIFF Options dialog box will appear. When saving as Photoshop PDF, the Save Adobe PDF dialog box will appear. The following Geographic Imager format option dialog boxes will appear for BigTIFF/DEM TIFF, ECW, DEM, GeoPackage, USGS DEM, ASCII GRID, and MrSID formats. Geographic Imager added formats may also have its own options dialog box.
When saving a non-spatial image format (e.g. JPEG or PNG), an external reference file is created in the same name. For example, an image with the file name VancouverCity.jpg will have an external reference file called VancouverCity.tfw (World reference format). Geographic Imager automatically updates associated reference files based on the latest transformation settings when saved. Change the default external reference format in Geographic Imager Preferences.
Caution: When saving an image after a Geographic Imager function is performed, Geographic Imager automatically updates the reference file. In this process, the original reference file is overwritten. In order to avoid damaging the original image and reference files, use the Save As command with a new file name or file location rather than using the basic Save command.
When saving to BigTIFF format, an image that has more than four color bands cannot be saved using the JPEG image compression option. For BigTIFF images in RGB or Grayscale color mode, using the JPEG image compression option only supports 8 bit RGB, RGBK or grayscale with less than four bands. Caution should be used when saving to BigTIFF using a script because it is possible to use the JPEG image compression option (doing so will produce incorrect results).
When saving to BigTIFF format with JPG compression enabled, the file size may be differ significantly when compared to saving to the TIFF format with JPG compression enabled. The image quality is on par between both formats.
When saving a DEM format with the Alpha Channel check box checked, the result will be that no alpha channels is saved. Digital elevation model formats like DEM, BIL and ASC don't support alpha channels.
Saving a USGS DEM format with the floating precision option creates files that may not be fully supported by some legacy DEM applications (values may be misread as integer).
Export Coordinate System Data
The defined coordinate system can be exported as a WKT Definition File (.wkt) or Esri Projection file (.prj) through the Geographic Imager panel options menu. Select Export Coordinate System from the panel options menu to access the Export dialog box.
Some reference files that do not store the coordinate system information (e.g. world file .tfw) will benefit from a WKT Definition File or Esri Projection file. These files stores all the parameters of the coordinate system that was exported.
Some projections are not supported when saving to a reference file and will not store the coordinate system. It is highly recommended to export a coordinate system file as well. See Reference Formats.
Export a Reference File
The defined coordinate system for a georeferenced image can be exported as a reference file through the Geographic Imager panel options menu. Go to Export Reference File from the options menu and choose one of the follow reference file formats to export to:
Reference file format
Reference file format extension
Blue Marble Reference File
MapInfo TAB File
.tfw, .tifw, .wld, .jgw, .pgw, .sdw, .eww, .blw, .dmw, .bpw
* The GeoTIFF option is only available when the current document is TIFF. Exporting a reference file to GeoTIFF is another way to convert a non-spatial TIFF to GeoTIFF.
Export functionality may also be used to change the referencing file format of an image. The georeferencing information should be first exported into the desired reference file format, then click the Reference File link in the Geographic Imager panel to specify it as the new reference.
If referencing of an image was changed after export, only the current referencing file will be updated; previously exported reference files will not be deleted or updated. The current reference file will be used and the old reference file will not. Keep this in mind when reopening images.