I have a point data as observer point with field attributes for Spot, offsetA, offsetB, Radius1, Radius2, Vert1, Vert2, Azimuth1 and Azimuth 2. For the raster file- a dsm with elevation data. They have the same projection and coordinate system

But when I run the viewshed analysis I get this error:

ERROR 010067: Error in executing grid expression. No valid Observation points present. Failed to execute (Viewshed).

Any suggestions how to solve this?

  • Does it work if you delete the field attributes? This will show if it is a problem with the data or the attributes. – Matthew Snape Mar 14 '13 at 14:03
  • Hi @MatthewSnape, I did. It created an output but the only attributes in the point file are ID and shape. But I need to input the parameters for SPOT, offsets, azimuths, etc. The numbers I use are the values in my analysis. Is it in the type of the fields? – Spencer Mar 14 '13 at 14:55
  • Could it be a problem with capitalization? (e.g. "OFFSETA" vs. "offsetA") Add them back in one at a time and see which breaks the tool! (I'm looking forward to seeing the result of this, I am currently learning viewshed basics for an upcoming project and it's nice to know what might break...) – Erica Mar 14 '13 at 18:06
  • hey @Erica! yeah.. I thought of that too. I followed the parameter settings prescribed by the tool, though it does tell you when a parameter is incorrect or does not pass a certain range. – Spencer Mar 14 '13 at 18:49

For a viewshed to work the Spot values need to be above the elevation shown on the Input Raster. For example a SPOT height of 11.5m within a DTM cell of 12m will cause that error. As an alternative try using an OFFSETA instead of SPOT.

  • 1
    +1. Another common reason is a misunderstanding concerning coordinate systems: if ArcGIS reprojects (or fails to project) the points into locations where there are valid elevations, this error will arise. – whuber Mar 14 '13 at 16:30
  • Thanks @Matthew! I tried changing the SPOT value as well as deleting it and using OFFSETA instead. Now, I get this error: ERROR 010160: Unable to open output raster Failed to execute (Viewshed). I think there is something wrong with my raster now.. – Spencer Mar 14 '13 at 18:48

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