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About ES Viewshed Application
The ES Viewshed Application is a web mapping application that provides
a means for PBO field engineers to conduct viewshed analyses
to aid in radio communication network planning. The application includes
basic GIS functionality of panning and zooming and custom tools
that allow the users to place points interactively and create
a frequency (i.e. how many sites can see certain locations) viewshed
for the placed points. The points can be placed in four ways:
latitude and longitude to a text box,
- graphical selection,
- 'find highest point' in an area of interest,
- upload a simple text file
Two other tools allow the user to get the latitude,
longitude and elevation of a point and a measure tool. Support
data to add geographic context to the area of interest includes,
but is not limited to, the locations of PBO sites and their
status, hillshades of the elevation model, existing GPS networks,
roads, and place names.
Intended uses of this application
Viewshed Analysis for one site:
Single site viewshed analysis may be used to depict areas in
the surrounding geography that are visible from a single, user
defined potential site. The single site viewshed analysis is
often used to establish if the potential site for a communication
relay has the ability to see surrounding GPS instrument locations.
Viewshed Analysis for multiple sites:
Multiple site viewshed analysis may be used to determine how
many user defined, potential sites are visible from the surrounding
geography. The returned analysis will depicts the number of
potential sites that are visible from any location within the
viewshed analysis extents. This analysis can be used to determine
the optimal location for a communication relay when examining
the location of multiple potential sites for GPS instruments.
Run the ES Viewshed Application
ES Viewshed Application Quick Start Guide
|Map Navigation and Information
||Pointer Tool – Use this tool to recenter the map by a clicking
on the desired recenter location
||Zoom In Tool – Use this tool to zoom in to the map. Either click
on a zoom in location or drag a box to zoom in to the box’s extent.
||Zoom Out Tool – Use this tool
to zoom out to the map. Either click on a zoom out location or drag a box
to zoom out to the box’s extent.
||Pan Tool – Use this tool to move the map. Click on the map, hold
down the right mouse button and move the mouse to move around the map.
||Zoom to Full Extent Tool – Use this tool to zoom to the extent
of ALL of the map layers.
||Get Coordinates & Elevation Tool – Use this
tool to get the coordinates and elevation of a point. Click on the map and the elevation
will be displayed in the message area at the bottom of the web page.
||Measure Tool – Use this tool to measure distances on the map. Click
once to start the measurement segment and click again to end the segment.
The measured distance will show up in the message area of the web page.
||Create Point Tool – Use this
tool to create a point to be used in the viewshed analysis. Click on the
map to create a point.
||Get Highest Elevation Tool – Use this tool to select the highest
elevation in an area of interest. Drag a box to create an area of interest
and the application will create a point at the highest elevation within
the dragged box.
||Set Viewshed Area Tool – Use this tool to select
the viewshed analysis area which will be the input to the viewshed analysis.
Activate this tool by clicking on the button and set the area by dragging
a rectangle in the map window.
NOTE: Be sure to include
at least ONE point in the viewshed analysis area drag box.
||Execute Viewshed – Use button to execute a frequency
viewshed for the sites within the viewshed analysis area delineated with
the ‘Set Viewshed Area Tool’.
||Create Point File - Use button to create a text file
of the points currently being displayed in the application
|Application Control Buttons
||Refresh – Use this button to refresh the analysis
session. WARNING: Refreshing the session will erase all placed sites and
previous analyses results.
||Exit – Use button to exit the application and
close the web browser.
||Help – Use button to access the Quick Start Guide.
Potential Site Location(s)
the points to be used in the viewshed analysis. Each point is created
individually using one of the following four methods:
- Enter the coordinate for the
site using WGS 84 decimal degrees and click the ‘Submit’ button.
the ‘Create Point’ tool to activate the interactive
site placement tool. Next position the cursor on the map where the
site is to be located. Finish by left clicking to place the site.
the ‘Get Highest Point’ tool to activate the Highest
Point Tool. Drag a rectangle to set the search limits to find the highest
point in an area. The result of this tool will place a site at the
highest elevation in the search rectangle.
- Upload a text file that contains
a list of coordinates of sites to be used in the analysis. Click the ‘Browse’ button
to locate the file on your local computer. Next click the ‘Upload’ button
to submit the sites to the application. For format questions, click the ‘Upload
Enter the desired
elevation offset for the analysis. The elevation offset allows the
user to create a viewshed based on an elevation that is added to the
elevation of the site on the underlying elevation data.
- The Potential Site Offset value
is the value that will be added to the elevation of the site, as derived
from the underlying elevation model.
- The Surrounding Elevation Offset value is the value
that is added to the ENTIRE elevation model when the analysis is
offsets are used for ALL points in the analysis. This option is helpful
when trying to compensate for the mounting of an antenna on a mast
of a known height at both endpoints of a point to point radio link. The
values are set to a default value of 2 meters.
Viewshed Analysis Area
Click the ‘Set Area’ button to activate the Set Area tool. Once the
set area tool is activated, drag a box in the map window to set the viewshed
analysis area. NOTE: Be sure to include at least ONE point in the viewshed drag
box. Next click the ‘Execute Viewshed’ button to create a frequency
viewshed for the sites within the viewshed analysis area.
Terms and Conditions