Visibility analysis - visible zone unrealistic

[DavidRalston]

Visibility analysis:

- I am getting the following output for visibility analysis

- The procedure doesn't take into account the fact that it is unlikely that a viewer can see more than 20km (depending on elevation of observation point), is there a way of incorporating this into the output?

[DanPatterson_Retired]

Did you try changing the default curvature from flat earth ?

https://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/visibility.htm

curvature_correction (Optional)

Allows correction for the earth's curvature. FLAT_EARTH —No curvature correction will be applied. This is the default. CURVED_EARTH —Curvature correction will be applied.

[DavidRalston]

Hi Dan, 

Couldn't see this option in Pro. Just looked in arcmap and it's greyed out, any reason for this?