Raster and tfw

[SabrinaScheitweiler]

Hello everybody,
i  hope someone can help me solve a small problem. We bought new topographic maps. The folder-structure is the same as before, we have one folder with the raster-images in it and included another folder with the tfw-data. But for some reason, arcgis does not automatically find the associated tfw-data in the other folder. If i put everything in ONE folder, it works. Anybody an idea why? And how to change?
Thanks in advance and regards,
Sam

[JakeSkinner]

The .tfw file will need to be in the same directory in order for ArcMap to read it correctly.  This is by default; similar to how all files (.shp, .shx, .dbf, .prj) of a shapefile need to be in the same directory.  I don't believe there is a way to have ArcMap read another directory in order to read the world file.

Any reason why you cannot have the world files in the same directory?

[SabrinaScheitweiler]

Thank you for your reply. I think, i could not express myself clearly...sorry. The tfw is in the same directory then the rasters, just in a subfolder and this is how it worked all the time before...nothing has changed (except that the raster-data now is in UTM) and thats the way we got the data...

[JakeSkinner]

The imagery you used previously may have had the image-to-world transformation stored in the header.  The header is read first.  So, the world file was most likely not being used.  See the following link:

http://resources.arcgis.com/en/help/main/10.1/index.html#//009t00000028000000

How georeferencing information is accessed

The image-to-world transformation is accessed each time an image is displayed, for example, when you pan or zoom. The transformation is calculated from one of the following sources, listed in order of priority:

    The header file (if the image type supports one)
    The world file (This will be used first if the Use world file to define the coordinates of the raster check box is checked on the Options dialog box.)
    The row/column information of the image (an identity transformation)