Novice seeking help on viewshed analysis

[ToddDonovan]

Hi all,

I'm a complete ArcGIS Pro novice.  I've been using ArcGIS Online to perform a rough analytic study for a customer related to potential coverage of many radar and communication sites over a very large area.  90%+ of this can be accomplished without problem using the online functions (viewshed, etc).  But one system I am trying to analyze has a longer range (40 miles) and both the online and read-to-use viewshed function is limited to 31 miles.  I'm basically trying to extend the viewshed ready-to-use function an additional 10 miles.  I've tried using the viewshed2 function in ArcGIS pro and can't figure out how create the raster surface I need as an input.  Selecting the World Elevation 3D gives an error that the model should be referenced to a spheroid. I'm short on time and looking for a quick fix to get a rough approximation.  Can anyone give me some tips?  

Thanks in advance!

[DanPatterson]

You would need a better elevation data set for your area.  Have you looked for anything that is available for your area?

[DavidPike]

Also be aware of whether you need a DEM/DTM or DSM.

[Robert_LeClair · Accepted solution]

Todd - I'd recommend you download an elevation dataset at or larger than your study area.  You can download elevation data at Data.gov - specifically the USGS National Elevation Dataset (NED) here.  Once you download your area of interest, project the data into a projected coordinate system and use the Viewshed or Viewshed 2 GP tool for your analysis.  In addition, you may want to consider limits to your viewshed using parameters such as SPOT, OFFSETA, OFFSETB and more.  You can learn more about offset parameters here.