Perspective Scene



Perspective Scene Basics

Perspective Scene, or pscene, is one of the NIMAMUSE Specialty Applicationsthat uses map data imported and built with other NIMAMUSE applications.Perspective Scene will help you visualize the shape and character of theterrain of you area of interest. As the diagram below shows, PerspectiveScene requires digital raster and elevation data which has been accessedby the NIMAMUSE Raster Importer.





The function of Perspective Scene is to draw an "out of the cockpit" viewover the input raster and elevation data based on a viewpoint, declinationangle and field of view that you provide. This image that you produce willhave a 3-D appearance in that mountains will appear tall and valleys deep.This is also known as "draping" the flat raster image over the digital elevationdata.

Operation of Perspective Scene is simple: once you have accesses and preparedyour raster and elevation data for input, you can generate as many perspectivesscenes as you like. Typically after you have generated a scene, you can refineyour perspective parameters and draw it again until your scene looks justright. You can also save your generated scenes in various formats to yourdisk.





Some Preparation

You must have a raster file and a co-registered elevation file in place onyour disk for input to Perspective Scene. These two files are accessed andprepared using the NIMAMUSE Raster Importer. In the examples on these pages,the prepared raster file is ADRG, and the prepared elevation file is DTED.Note also that when you identify the Basemap ADRG data in a file selectionbox (see below), the corresponding prepared DTED file will be loadedautomatically provided that it is co-registered to the raster file, thatit resides in the same directory as the raster file, and that it also hasthe same first-part filename as the raster file (the DTED filename's extensionmust be ".dte"). As the example below shows, choosing "512phil3.adr" willautomatically load the DTED file "512phil3.dte" which is in the samedirectory.






Perspective Scene Graphic Interface

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






The four display windows of Perspective Scene are shown below. The BasemapWindow, which displays your raster input with observer position and Pointof Interest position, is in the upper right. The Data Entry window is inthe upper ,left. The Basemap Status window is in the lower right, and theperspective scene that you generate is show here in the lower left, labeled"lastview".







In the Data Entry window, you can refine your generated scene by manipulationof all the parameters shown.

Your input raster file is shown in the Basemap window. In this window, theparameters are graphically reflected in the field of view lines and observerand point of interest positions. Note that you can also reposition in theand observer and point of interest positions in the Basemap window to manipulatethe display parameters.

The Basemap Status window shows a continuous readout of your cursor positionin latitude and longitude within the Basemap window.

The lower left window labeled "lastview" holds the most recent perspectivescene image that you generated based on the current parameters you selected.The screen picture below illustrates a pulldown menu in the "lastview" windowthat lets you save your image in Sun Raster Format, in Windows BMP Format,or NIMAMUSE Native RGB Format. Be sure to refer to thePerspective Scene Application Referencefor a complete account of all the pulldown functions and options.





Other functions on the Perspective Scene top level command menu bar areillustrated in the pictures below. Under "Reset", you can return to earliersettings. Under "View", you can choose an active window, and zoom in andzoom out in the Basemap window. As usual, refer to the detailedPerspective Scene Application Referencefor full details.










Some Advice on Viewpoints, Declination Angles, and Fields ofView

Good-looking 3D perspective scenes are generated from dramatic view points.However, the desire to select dramatic view points can produce surprisingor disappointing results. Looking toward a mountain from a plain is muchmore effective than looking down from a mountain top to a valley floor. Lowviewpoints created by low declination angles (+/-), can usually create verydramatic scenes as the terrain relief is displayed at its best. However,high viewpoints ( created by high declination angles ), usually result indisappointing scenes because the terrain relief is fore-shortened and sois dull looking.

Wide fields of view that exceed 60 degrees are comparable to wide-angle lensesand can result in very dramatic scenes. However, fields of view around 90degrees or more can prove quite unnatural views and cause confusion to aninexperienced user.

Narrow fields of view that are less than 30 degrees are similar to telephotolenses, and very narrow fields of view can result in fore-shortened sceneswhere because the depth of scene cannot be easily discerned, the scene looksunnatural.

Where possible, viewpoints should be picked with these guide lines in mind,because a dramatic scene is a communicative scene, and provides powerfulevidence of the link between 2D maps and the actual 3D scene. But a scenethat lacks realism or lacks impact can cause doubt and confusion if the usercannot recognize the relationship between map and 3D scene.


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As stated, for complete details on Perspective Scene, refer to thePerspective Scene Application Reference: PSC_UG.DOC. In this reference, there are ten tutorials you can do thatwill walk you through all the steps necessary to make and save your ownperspective scenes. Also, while running Perspective Scene, there is on-linehelp available via a pulldown menu on the Perspective Scene top level commandmenu bar.


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Related NIMAMUSE Documents


Perspective Scene Application Reference   PSC_UG.DOC

Line of Sight    LOS.DOC

Line of Sight Application Reference   LOS_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