Using ArcMap 10.3, I want to digitized only the pale blue polygons in the raster into shapefile with "Raster to polygon" tool. This is the raster:


I get a shapefile with gridcode field, but i don't no how to isolate the right features of the pale blue color:

UPDATE: this attribute table as 224000 features, i just show the first features in this picture:



I use unique values symbology and get this result (I deleted useless features from attribute table):


For clarity, I asked this question in https://geonet.esri.com/thread/165906.

1 Answer 1


Firstly I have to say I am little confused, so I will prefer write some comment before answering, but I haven't enough reputation points to write a comment so I will put everything here.

From your pictures I am assuming that you have multiple band aerial imagery. So when you click it with identify you see values like Red, Green, Blue. If you wish to know the gridcode value in your polygon result, you have to firstly combine these values to one single value (i think that the raster to polygon tool is doing this in first step). Bear in mind that result of this would be greyscale raster, so you will probably need to identify your areas with the help of original raster.

Now how to do it. This should work without extensions (at least with version ArcGIS Standard):

  • click Windows -> Image Analysis

  • in Image Analysis Window -> check and select your raster -> in processing tab click add function button -> in new popup window right click your raster -> insert ->greyscale function ->ok

  • this should provide new raster layer with single integer values. Click with identify on this layer and read the pixel value for your area of interest

  • convert this layer with raster to polygon. The gridcode field of resulting polygons holds the pixel value from your greyscale layer

Hope this helps.

  • Hi makak, i don't have extention. is there another a solution for my issue?
    – newGIS
    Dec 3, 2015 at 6:08
  • So your raster is floating point? I just need to know if you are able to convert it with raster to polygon. If yes you, don't need any extension and you can separate desired polygons just by querying gridcode field. If this is not the case and your raster is floating point, let me know and I will try to describe how to do it without extension.
    – makak
    Dec 3, 2015 at 6:30
  • i don’t know if this is floating point. how can i upload the layer?
    – newGIS
    Dec 3, 2015 at 13:58
  • @newGIS I have think about it one more time and I think you have multiband imagery. I have change my answer. I think this should work for you...
    – makak
    Dec 4, 2015 at 8:04

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