If you check Options, Menus tab, Show labs:
Otherwise
Download data files for Sensor Placement Exercise at http://www.usna.edu/Users/oceano/pguth/downloads/sensor_placement_lab.zip.
This gives you a DEM and the NLCD for a location on the Arizona border, in the region where DHS had a large demonstration project called P28 which was part of the Secure Border Initiative (SBInet).
The diagonal green line is the border which we want to cover with
sensors, represented by a thin shapefile. The locations of 6 sensors and their Viewsheds are also shown. We will calculate the sensor coverage by the percentage of the border shapefile that is in the the visible portion of the viewsheds for the sensors. |
Turn in:
Word document with maps showing your coverage, and a printout of the results, for three different arrangements of 5 sensors selected from your 10. Include a discussing of:
![]() |
You will use sensors with the following characteristics, set on the Viewshed Parameters window. The size of the towers matches news reports, but the characteristics of the sensors (radar, infrared and other according to the news reports) are hypothetical.
By default, the program will save the viewsheds in c:\mapdata\temp, which will be cleaned out when you close the program. You might want to change that location, with the Path button on the bottom of the form, to the directory you are using for the lab. The program can regenerate the fans if you save the sensor locations, but you can can save some time by saving the viewsheds in a safe location. |
New DEM and
load the DEM and NLCD. Locate the international border.
You can note this as an artefact in the DEM, or overlay the state or
county borders on
the map. You can also look at the NLCD, and note the change in coverage at
the border. You probably want a grayscale reflectance
map.
Annotate Map,
Create
shapefiles, to create an area
shapefile for the international
border. You are creating a small area that covers
the border so that you can determine the effectiveness of sensor placement.
Insure that the shape file plots with a solid fill pattern (Symbol and color selection). Fan coverage
computations will do an intersection of this region with the fan coverage.
1:1
map view (best resolution view of
the data, and best chance to get optimal sensor placement)
Go to the Coordinates tab on the Options form, and pick Reasonable for "Verify graphical selection", and "Graphical blowup" for the Verify option. Graphical selection might not be very precise, and could place sensors in holes from which they might not see very much. If you know coordinates, perhaps from a GPS field survey, you could pick the option to type them in from the keyboard.
Weapons
fan/viewshed. Place at least 10 sensors to attempt
to cover the border. Insure that you correctly:
Set the parameters given above for each sensor in the Viewshed parameters window. This is especially important for the first sensor, since the settings will be remembered for the others. Set the horizontal viewport with the left and right boundaries, and the vertical viewport with the min and max inclinations, and minimum and maximum ranges.
If you fans are not showing check:
![]() |
Check the opacity, set with the slider on the Sensor panel; Pick a midrange opacity for the fans, which will let you see the terrain behind the fans.. |
After you have entered the sensors,
The key options:
last revision 4/18/2017
.