Warren H. asks:
I have just purchased ExpertGPS Pro with GIS support. I would like to add some of the orthophotos I use in Arcview to this program. I have world files for these images. I know I can manually “calibrate” the images, but that is not nearly as accurate as the information from the world file. Is there any way to manually enter the information from the world file to calibrate the image, or do I have to estimate points by selecting a point and assigning a lat/lon to the point?
How to Import Orthophotos with a World File into ExpertGPS Pro
ExpertGPS Pro will read the worldfile accompanying your orthophoto and extract the geo-referencing information from it. All you have to do is change the File Type selector in the Add Scanned Map dialog, so that you can select the World File rather than the image itself.
Click Open Scanned Map Library on the Map menu, and then click the Add button. This will bring up a “browse for file” dialog where you can select the image to import. At the bottom of this dialog is a file type selection drop-down list, which by default is set to select the image file itself (.jpg, .tif, .png, .bmp). Change this selection to World File (.jgw, .tfw, .pgw, .bpw) and now you can select the World File that accompanies your image.
ExpertGPS will do the rest. All you have to do is click the Edit button in the Scanned Map Library, and select the correct projection and datum. ExpertGPS Pro has already imported all of the geo-referencing data from the worldfile.
ExpertGPS Help File: Add Scanned Map command