Line of Sight




Line of Sight Basics


Line of Sight, or los, is one of the NIMAMUSE Specialty Applications thatuses map data imported and built with other NIMAMUSE applications. This programprovides you with an easy way to determine the visibility of a line of sightto a target based upon the topography of the surrounding area. Line of Sightbuilds a line-of-sight display and a profile display.

Line of Sight will help you visualize the shape and character of the terrainof you area of interest . As the diagram below shows, Line of Sight requiresdigital raster and elevation data which has been accessed by the NIMAMUSERaster Importer.





The functions of Line of Sight are to build a line of sight display and profiledisplay. The line of sight display reflects areas of visibility andnon-visibility with respect to a observer position that you select. The profiledisplay is a cross section of the terrain from an observer position and atarget position that you select. Examples of both of these appear below.

Operation of Line of Sight is simple: once you have accessed and preparedyour raster and elevation data for input, you can generate as many line ofsight displays and profile displays as you like. Typically after you havegenerated a display, you can refine your positions and draw it again untilyour display looks just right. You can also save your generated displaysin various formats to your disk.







Some Preparation

You must have a raster file and a co-registered elevation file in place onyour disk for input to Line of Sight. These two files are accessed and preparedusing the NIMAMUSE Raster Importer. In the examples on these pages, the preparedraster file is ADRG, and the prepared elevation file is DTED. Note also thatwhen you identify the Basemap ADRG data in a file selection box (see below),the corresponding prepared DTED file will be loaded automatically providedthat it is co-registered to the raster file, that it resides in the samedirectory as the raster file, and that it also has the same first-part filenameas the raster file (the DTED filename's extension must be ".dte"). As theexample below shows, choosing "botlm768.adr" will automatically load theDTED file "botlm768.dte" which is in the same directory.







Line of Sight Graphic Interface

In the detailed Line of Sight ApplicationReference , there are thirteen tutorials you can run. Tutorial One coversstarting Line of Sight for each platform supported by NIMAMUSE. Once started,you get the Line of Sight top level command menu bar. This is shown belowwith the "Load Raster Image" pulldown fully exposed:






The three display windows of Line of Sight are shown below. The Basemap Window,which displays your raster input with observer position and target position,is in the upper right. The Data Entry window is in the upper left. The BasemapStatus window is in the lower right.






The line of sight display that you generate is a circle of colored areasand it is overlaid on the Basemap window. An example of this is shown directlybelow. The different colored areas of this circle represent the differentareas of visibility and non-visibility based on the observer position atthe center of the circle and on the terrain surrounding the observer. Notethat on your display, this circle area will be in the colors listed in theBasemap Status window; it is only on this page that these examples appearin shades of gray.






For best results, after the color "visibility" overlay is generated in theBasemap window, you can dim the raster map background to better view boththe raster map and the color overlay together. You can control this dimmingby clicking on the "Adjust Map Contrast" item on the "View" pulldown of theLine of Sight top level command menu bar (see an example of this pulldownbelow). A map contrast control window will appear for you to interactivelyadjust the contrast in the Basemap window.

The other display window in Line of Sight is the Profile window. A crosssection of the terrain from the observer to the target is plotted on a gridof Range to Target vs. Elevation. The cross section curve itself is displayedin the same visibility color codes as the visibility area display shown above.. There is also a cursor-movable legend in this window which displays pertinentinformation about the profile.






To save your displays, click on "Save Product" on the "File" pulldown ofthe Line of Sight top level command menu bar.

Other functions on the Line of Sight top level command menu bar are illustratedin the pictures below. Under "Reset", you can return to earlier settings.Under "View", you can choose an active window, zoom in and zoom out in theBasemap window, and adjust map contrast in the Basemap window. As usual,refer to the detailed Line of Sight ApplicationReference for full details.










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As stated, for complete details on Line of Sight, refer to theLine of Sight Application Reference: LOS_UG.DOC. In this reference, there are thirteen tutorials you cando that will walk you through all the steps necessary to make and save yourown line of sight displays. Also, while running Line of Sight, there is on-linehelp available via a pulldown menu on the Line of Sight top level commandmenu bar.



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Related NIMAMUSE Documents


Line of Sight Application Reference   LOS_UG.DOC

Perspective Scene    PSCENE.DOC

Perspective Scene Application Reference   PSC_UG.DOC

Raster Importer   RAST_IMP.DOC

Raster Importer Users Guide  RAST_UG.DOC

Fusion   FUSION.DOC

Fusion Users Guide   FUS_UG.DOC

Access and Prepare NIMA Digital Data  APNDD.DOC

Build Your Own Map   BYOM.DOC

Run Specialty Applications   RSA.DOC

NIMAMUSE 2.1 Documentation   INTRO.DOC