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I'm struggling with a visibility analyses task in ArcMap.

I have two objects: a spire and a WTG (wind turbine generator). Both are point features. The object's heights are deposited in the attributes table (WTG ~200 m, spire ~15m). Surface data is provided by a raster DEM25.

What I want to find out is: Which WTGs are not visible from a certain observation point (spire) (due to the mountain effects of the DEM).

Is the only/best way to do this using the viewshed tool or is there a smarter tool available?

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The best way is to use viewshed (observer point does not seem necessary based on you question, except if you want to know which spire can see which WTG). First you determine the locations where you could see your WTG (viewshed of the spires), then you use "extract multivalue to point" to transfer this information from the resulting raster to each WTG point. If you wtg is within the viewshed, then it means that it is visible.

When using Viewshed, the point FC with the spire must include 2 specific fields (more details here) : OFFSETA and OFFSETB. OFFSETA will be the value of the spire height (15) and OFFSETB the value of the WTG height (200).

Last but not least : make sure that XY are in the same unit as Z, or use the conversion coefficient.

  • I needed to know, which WTG are visible and which are not. I solved this by using the "Construct line of sight" and "line of sight" tools. It was only possible by using a dummy multipatch file to get a streight line of sight between the observer and the target. Otherwise the line was drapt to the surface. – Jon Aug 26 '15 at 12:46
  • thank you for your feedback. It would be even better if you could put it as an answer if you solved your problem (and accept it after 48 h to show that it has been solved). I would also be interested to know why my method didn't work for you. – radouxju Aug 26 '15 at 13:12

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