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I am trying to use the shapefile here: https://environment.data.gov.uk/DefraDataDownload/?mapService=EA/HistoricLandfill&Mode=spatial to work out how much of the sites are covered in trees. I have managed to load the shapefile and aerial images (World Imagery basemap) and clip the map to just show the imagery within the polygons. Now I would like to classify how much of each polygon is covered with trees however the classification tool is greyed out (I think because it is not a raster file). Is there any way around this? I am using ArcMap 10.1.

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    Do you have any prior experience with image classification? – Erik Oct 18 at 11:36
  • Unfortunately not, although I have done quite a bit of reading/googling I can't seem to get to the stage that will allow me to use this tool. Any help would be massively appreciated. – alice.fraser-mcdonald Oct 18 at 11:42
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    You will likely not be able to use imagery located in a service for classification. If you can find suitable imagery, given your question, I would not recommend classification at the polygon unit level. Perform a pixel level classification using supervised or unsupervised and then summarize the results to your polygon units. Else-wise you will be forced to classify each polygon as forest/non-forest and not be able to get at proportion of forest in each polygon. From where it sounds like you are at, please seek help from somebody versed in image classification. – Jeffrey Evans Oct 18 at 16:30
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Without access to your data it is difficult to speculate what the issue is. May be it's the format of the data or may be it's something completely different such as a daft file name that is invalid? If you have no prior experience to image classification then I would recommend you start playing with the isocluster tool (unsupervised). This is one of the easier tools to get to grips with as you basically chuck the raster at it and say how many classes you want. There are more superior techniques but if this tool throws an error it should at least help you track down the source of the problem...

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