Known Limitations

Due to the fact that the user can deal with DEM data and high resolution satellite pictures it is necessary to set limitations to the functioning of 3DTarget.

Because the first calculation comes from the importation of the XYZ file of points, the user has to be given an idea of the number of points the program can manipulate.

On the other hand, the other type of data brought by MICRODEM or the user, is the picture that plays the role of the texture of the VRML file. The user needs a great resolution, especially for the 2D View, if he has to locate target buildings or vehicles for instance. But this resolution is limited not only by the capability of 3D Target to display an image but also by the capability of the VRML files viewer Cortona that cannot display great size texture.

So, we made several tests with various numbers of points and sizes of picture. The computer used during this operation was Personal Computer with a Atlon 1.13 MHz processor, 260 megabytes of Random Access Memory, a ATI Radeon Video Card and Windows 2000. Thus the indicative calculation and loading times (in minutes and seconds), and also the maximum size of texture loadable by Cortona can be seen in figure 17.

 Indicative calculation and loading times (in minutes and seconds) and maximum size of texture loadable by Cortona.

In view of these results, the program can either be used to have a general view of a large area, or to work on a special and well determined area. Moreover it is not necessary to work on greater than 20000 points files to get a good rendering. Although it is dealing with massive data, the application is quick enough.

Last revision 4/21/2002