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I have georeferenced some image TIF files in ArcGIS 9.3. Update Georeferencing creates a *.TFWX file. Renaming to *TFW file does not place the image in the correct spatial location for software packages outside ArcGIS.

Is their a tool? converter? or method that will allow me to extract the correct georeferencing information from TFWX to TFW so that my image can be used in other Mapping platforms?

Hope someone can help. Many thanks

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How correct must it be? I use the rasters as backgrounds and they are just fine for that purpose. The usual reason they don't show where they should in other software is they still need to be properly projection defined, the world file doesn't contain any projection information. –  johns Feb 20 at 14:13
    
They need to be 100% correct. I have images of drainage information and I have to supply georeferenced TIFF files with a TFW world file. ArcGIS creates a TFWX file which is not the same! How can I derive this georeferenced information from the TFWX file to a TFW file. Looks perfect on screen in ArcMap. Surely this can be derived somehow!?! –  Adam Feb 20 at 14:39
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the answer is : it depends. But usually this is not possible because the tfwx file is only an approximation of the precise transformation using an affine transformation. The transformation is written in the aux.xml file. More details in the arcGIS doc

if the transformation cannot be expressed as a world file, Update Georeference writes the transformation into the aux.xml file and also writes an approximate affine transformation into a text file or a world file with an 'x' on the end of the extension name. For example, a TIFF image with this approximate affine transformation has the extension .tfwx. This is not an exact transformation; it is only an approximation.

If you want a tfw (affine transform), you should "rectify" your image instead of georeferencing it. A new resampled image will then be created, which can be accurately georeference using a world file.

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The TFWX file is sort of a world file but not in the conventional sense because it works in conjunction with the AUX.XML file. Therefore, if the Aux file gets lost, changed or cannot be read by some software you transfer your raster to, then the TWFX will not put the rather in the correct world position. To permanently transform the image you need to rectify it rather than rely just on 'update georeferencing'.

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