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I am a complete novice where it comes to ArcGIS.

I want to be able to extract a series of presence/absence (simple 1 or 0) values in x,y format from a projected future distribution map for a bird species in Europe.

I used R (someone else's code though)to forecast the future distribution. I added the raster images from R (which were in Disc Image format originally) into ArcGIS and converted them to TIF format. I've tried converting the TIF file to a shapefile using Conversion tools -> from raster -> raster to point, but it does not preserve my presence/absence pixels. Instead, I just get a gridded map with no indication as to whether the cells were projected to be presence or absence....

Shapefile - which I've zoomed in more on so you can see the individual 10x10km cells

... The actual presence/absence raster looks like this....

TIF raster with presence in dark blue and absence in light blue

Is there a way in which I can extract the x and y co-ordinates for presence (dark blue) and absence cells (light blue) using ArcGIS?

  • Did you specify a Field parameter in the Raster to Point tool? If so, the Y/N value should be stored in the attribute table of the points. – GISGe Dec 5 '16 at 13:19
  • No I didn't, where would I find the information to insert into the Field parameter box? Currently the attributes table contains the following column headings: FID, OBJECTID, pointid, grid_code, x, y... I was expecting the grid_code column to contain 1 (for presence) and 0 (for absence) but this hasn't been the case. Thanks for your reply. – JoeL5475 Dec 5 '16 at 14:22
  • Yes grid_code should hold the pixel values. When you run the tool, the Field parameter should automatically be populated with 'Value', try do do it manually if it doesn't. And if if still doesn't work, you could first set the cells with 0 to NoData with the Set Null tool, then export the raster to points, so that only the '1' cells will be exported – GISGe Dec 5 '16 at 14:36
  • Thank you ever so much. I manually typed 'Value' in the Field box as you said and I can now differentiate between the presence and absence cells. – JoeL5475 Dec 5 '16 at 14:53
  • Great! I've turned my comment into an answer so that you can check to mark your question as solved. – GISGe Dec 5 '16 at 14:59
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The grid_code field in the output of Raster to Point should hold the pixel values. When you run the tool, the Field parameter should automatically be populated with 'Value', try to type it manually if it doesn't.

And if if still doesn't work, you could first set the cells with 0 to NoData with the Set Null tool, then export the raster to points, so that only the '1' cells will be exported.

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