Map GPS Coordinates - GPS Map Coordinates ... - Global Mapper

Global Mapper User's Manual
The Obstructions from Vector Data section allows the user to specify whether or not loaded vector
data with elevation values should be considered when performing the view shed analysis. This allows
the user to use things like buildings, fence lines, towers, etc. to block portions of the view, creating a
more realistic view shed. If the user elects to use vector data, they can also specify whether the
elevation values stored with vector features are relative to the ground or relative to mean sea level.
Typically heights for vector features are specified relative to the ground. If any area features are
included and their heights are relative to the ground, the obstruction heights within those areas will be
increased by the specified amount, but any receiver heights will still be based on the terrain. This
makes things like wooded areas very easy to model. The Obstruction Area Features Always Hidden
option allows you to specify that any locations within an obstruction area will be marked as hidden,
rather than only those that actually would be hidden.
If checked, the Display Hidden Rather than Visible Areas option causes the generated view shed to
cover those areas that would NOT be visible, rather than those that would be visible from the
transmitter location.
If checked, the Generate Area Features in Covered Areas option specifies that view shed coverage
area (polygon) featuers should be generated for those areas that are visible. These generated area
features then behave just like any other vector feature and can be exported to vector formats, like
Shapefiles, for use in other software.
Pressing the Select Transmitter Location... button displays a dialog that allows the user to adjust the
exact transmitter coordinates from the coordinates where they clicked.
Pressing the Select Display Color... button displays a dialog that allows the user to select the color in
which to display the visible areas on the map.
After setting up the view shed calculation in the dialog and pressing the OK button, the view shed
analysis will be performed and when complete, the results will be displayed on the main map display
as a new overlay. All visible areas within the specified radius will be displayed using the selected
color. The overlay will default to being 50% translucent, allowing you to see areas underneath the
view shed. You can modify the translucency of the overlay in the Overlay Control Center.
In addition, a small radio tower point will be created at the selected transmitter location. When
selected using the pick tool, this point displays information about the view shed analysis as shown
below.
If you would like to modify the settings used to calculate the view shed and recalculate it using
currently loaded data, you can right click on the View Shed layer in the Overlay Control Center and
select the option to modify the view shed.
Map GPS Coordinates - GPS Map Coordinates - GPSCoordinates Map 171