PNG Raster to XYZ Table

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08-14-2013 10:40 AM
RyanLove
New Contributor
Hello All,

First things first, I am fairly new to ArcGIS so if I've missed something obvious, that would be why. Basically what I have is a figure in PNG format which I have imported into ArcGIS as a raster and I want to get out values for each point on the figure as an xyz table(lon, lat, value). I have gotten it geo-referenced alright I believe as the boarders on my imput data line up with that which I've set up for reference(A Hammer_Aitoff projection). The things I've been having trouble with is getting the data into the table with lon lat for x and y, I always seem to wind up with some strange co-ordinate system in the 80K+ region of values. I'm using the spatial analyst>Extraction>Sample tool and setting the output co-ordinate system to that of my display since I assume that is the co-ordinate system I would want since my cursor shows lon and lat values for any given point. Also I would like to sample the colors on my figure and assign those to specific values to save me the grief of coding up a python script to match each RGB value to a numerical one, I assume this is fairly trivial and I've just not found the function yet.

Cheers and thanks
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1 Reply
EricRice
Esri Regular Contributor
Ryan,

The display units are not actually connected to the coordinate system of the dataframe.  It's probably returning X,Y in A Hammer_Aitoff projection space.  To get X,Y in Decimal Degrees your coordinate system on the dataframe needs to be in a GCS.  To confirm, go to the General tab of the dataframe properties.  I bet your Map units are Meters, and your Display units are Decimal Degrees.

Best,
Eric
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