Curvature option for Line of Sight is not enabled

Description

When using the Line of Sight tool, the Curvature option is not enabled.

Cause

Specific criteria are not being met for the Curvature option to enable.

Note:
This information only pertains to ESRI GRIDs.

Solution or Workaround

1. The surface must have a spatial reference. Check for spatial reference by right-clicking on the image > Properties > Source tab > Spatial Reference.
2. The surface must be in a projected coordinate system.
3. The Z units of the surface must be defined.
   
   Summary:
   Instructions provided describe how to define Z units for a GRID.
   
   Procedure:
   Follow the steps below:
   
   

   1. Open Windows Explorer.
   2. Navigate to the location of the GRID.
   3. Open the folder with the name of the image.
   4. Right-click on 'prj.adf' > Open with... > select Notepad or Wordpad.
   5. Of interest is the ZUNITS parameter. It may be absent or set to a value of 'NO' or 'NONE'. Change this to FEET, METERS, or a floating point value which represents units per meter.
      
   6. Save the changes. The Z units are now defined.