by emorse4487 » Fri May 14, 2010 2:20 pm
You have to extract the world file from the image before you can place it.
From the GIS toolbar:
Images>Image World File>Extract From Image
Make a copy of this world file and store it somewhere else (see note below).
Now, if you're GIS data is in meters you need to apply a scaling factor to the world file that you just created in order to use it for survey work.
Images>Image World File>Edit World File
Open the world file you just created and click Change world file scale factor. Put it in whatever scale you want.
NOW, if you're working on a different coordinate system than your GIS data is in, you need to do a coordinate transformation as well. There are some tricks to this which will negate the need to change the world file scale. If you need help, let me know.
Provided you don't need to do a coordinate transformation, run the "place by world file" command and place your image using the extracted (and subsequently modified) world file.
Note:
Working with Carlson GIS is a pain in the ass. All of our GIS data is in meters, which is fairly useless for my purposes. There is no easy way to tell if an image world file has been scaled. Some of our technicians have re-scaled world files that were previous converted to feet, which causes an even bigger mess of not knowing which world files are valid without going through them all. Make a copy of your original world files and put them in a special folder BEFORE you convert them. That way when something goes wrong (and it probably will) you have a backup.
These scaled image files will also wreak havoc on ESRI ArcGIS if you aren't careful. ESRI does the coordinate transformations automatically and if you place the image by a modified world file you'll be in trouble.
Hope that helps.
(This is all pursuant to the fact that you are running or have access to Carlson GIS. You can't do it with Survey alone, as far as I know.)
Eric J. Morse, P.E.
MEC Industries, LLC