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I am working with Erdas Imagine's Signature Editor to perform maximum likelihood classification. I need to use the same training set created in Erdas for other classification using R. Is there a way to extract the raster band pixel values under the .aoi polygons and export that information to a .txt or .csv? I am looking for the same functionality as the ArcGIS Sample tool where the individual raster band pixel values are extracted underneath points and written to a table (e.g. Figure 2). Alternatively, is it possible to export the signature editor table (i.e. including R,G,B,NIR bands and the class label) to a .csv? Any workarounds on how to integrate Erdas's signature editor with the analytical functionality of R would be very helpful.

For example, I need the functionality of the signature editor

Figure1 enter image description here

Yet I need to convert these values to a format that I can read into R. Note that I need all four bands of the input image along with a class ID (i.e. grid code). This table was generated in ArcGIS.

Figure 2 enter image description here

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Can you upload a sample of your sig file? I'd like to have a play around with the file, but don't have erdas installed in the office. Thanks. –  sgrieve Nov 20 '12 at 9:10
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@sgrieve I've uploaded the .sig to a file sharing service:wikisend.com/download/372268/maxlikesig.sig –  Aaron Nov 21 '12 at 3:59
    
Thanks, I've not had any joy pulling any data out from the sig file. I can't find any documentation on the format, so I am going at it blind unfortunately. Hopefully someone else will have some more luck. –  sgrieve Nov 21 '12 at 9:24
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I have been using this software (gdargaud.net/Hack/BinToAscii.html) to try and reverse engineer the sig file, but its trial and error to get the data in the correct format. –  sgrieve Nov 21 '12 at 9:49
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It has been a while since I used ERDAS, but I believe you can export .aoi to ASCII. In ERDAS, Utilities>Export pixels to ASCII. ?? Then you could load that into a CSV file. You can also convert your .aoi file to .shp, which you could then use with the ArcGIS sample tool you mentioned.

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