Line of Sight with Observer Height

[SaraMayberry]

I can construct Lines of Sight with no problems if I leave the values for the Observer and Target Heights at None.  Of course this isn't too helpful when you're talking about wanting to know who will have view of a cell tower being built since cell towers are not 0ft tall.  When I rerun the tools to create the Lines of Sight using a Height field, I end up with all red lines.  No green whatsoever.  Any ideas on what I'm doing wrong?  It works fine if I use the 3D Analyst Toolbar Create Line of Sigh button with the height value changed, but I dont want to draw that many lines by hand.

Thank you for any input!

Sara

[PavanYadav]

Please see Jeff Swain's reply at this forum. Example: your DEM has elevation range between 150 and 2000 meter and when you create a point for a200m high tower that is located at a 300m above the sea level location (on the DEM value is 300m), you should use 500m not 200m height. A 200m high point for 300m elevation location will be below the surface.

Regards,
Pavan