Line of Sight/Topographic Profile

LOS Example and Uses--in earth science, "topographic profile" or "cross section"  is the correct terminology.  Line of sight is for military or radio/radar applications concerned with intervisibility.

• DEM must be loaded and assigned to current map,
• Start with:
  •   or on main toolbar
  •  “VIEW, LOS” menu option.
  • Calculate, Intervisibility, Line of sight menu choice
• Move mouse on map and double click to select observer's location, which will be on the left side of the profile. Coordinates and elevation of the mouse are displayed at the bottom of the map. Verifying point selection may be advisable, and is set on the Coordinates tab of options menu. LOS requires at least "reasonable" to trigger point verification.
• Move mouse pointer. A reverse video line connects the observer location to the target location. Double click on the desired target location. Verifying point selection may also apply here.
• If you have a long profile, the program will verify if you really want to use vertical earth curvature.  Say No for just a topographic profile.
• A new LOS window displays the graphical line of sight.

LOS Right click options--analysis options, including turning LOS into topographic profile.

File menu options:

• Open profile database: this has the coordinates, and distance along the profile, of the points used to draw the profile.
• Print
• Edit image
• Save image
• Copy to clipboard
• Close

Notes:

• To change vertical exaggeration, change size and aspect ratio of the graph window by clicking and holding down the mouse button on the edge or corner and dragging.
• Force a specific vertical exaggeration from Modify menu or by right clicking.
• Change vertical earth curvature algorithm.
• Moving the mouse in the profile window displays ground coordinates and elevation on the panel at the base of the window.
• For radio line of sight the program can draw Fresnel zones.
• Create a terrain profile from a line shapefile.
• Vegetation grids can be loaded and used for intervisibility masking.  Toggle vegetation effects on and off by Right clicking on the view

Last revision 11/16/2014