EarthScope
Viewshed Application

System Requirements

Web Browser

  • Internet Explorer 5+ (Recommended)
  • Java must be installed/enabled (IE has it enabled by default)

Monitor Resolution

  • Recommended: 1024 x 768

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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:

  • input latitude and longitude to a text box,
  • graphical selection,
  • 'find highest point' in an area of interest, and
  • 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

Launch the ES Viewshed Application

ES Viewshed Application Quick Start Guide

Map Navigation and Information Tools
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.
Site Placement Tools
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.
Viewshed Tools
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)
Create the points to be used in the viewshed analysis. Each point is created individually using one of the following four methods:

  1. Enter the coordinate for the site using WGS 84 decimal degrees and click the ‘Submit’ button.
  2. Click 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.
  3. Click 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.
  4. 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 Help’ button.

Elevation Offsets
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.

  1. 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.
  2. The Surrounding Elevation Offset value is the value that is added to the ENTIRE elevation model when the analysis is run.

These 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.

Technical Support

Terms and Conditions

 

 
 EarthScope
IAGT, Inc. Developed by the Institute for the Application of
Geospatial Technology with support from the
National Aeronautics and Space Administration

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