Terrain Modeling Features

Compass has the ability to create terrain models of the survey above a cave and display them in the Viewer. The terrain models can be entered manually or read from Digital Elevation Model files available for the USGS. With a 7.5 minute quadrangle, you can get very high levels of resolution. Here is a 7.5 minute model of the terrain around Groaning Cave

Building Terrain Models

To build a terrain mode, the Compass DEM Reader loads a Digital Elevation Model file into memory that contains thousands of elevation points that describe the terrain in a particular area. The image to the below shows an overview of the terrain contained in a DEM file.
In this case, the image shows the terrain using the "Color-By-Elevation" mode This image is a segment of the White River Plateau north of Glenwood Springs, Colorado. The deep blue valley running across the bottom of the image is the Colorado River.
This image shows the shaded relief mode. The image looks like a black and white aerial photograph. It is another view of the White River Plateau north of Glenwood Springs, Colorado. .Again, the deep valley running across the bottom of the
image is the Colorado River. You can see the river cutting through the "Grand Hogback" on the lower left. These two images are used to select the terrain that you will attach to the cave.

Once you selected a portion of the terrain to use with your cave surveys, the terrain is attached to a plot file and can then be displayed in the Compass Viewer. The image above demonstrates the capabilities of the DEM Reader program. It is an image of about 50 square miles of the White River Plateau from the southeast. To give you idea of the scale, if you are viewing this on a 15 inch monitor one inch equals one mile. To the right is Deep Creek Canyon. Groaning cave is barely visible beneath the grid lines the hills to the west. With the Windows or DOS viewer, you can pan, zoom and rotate the image in such a way that you can literally fly down the canyon and over the ridges. With the new movies features, you feel like you are riding in a flight simulator.

Estierra - Terrain Modeling Program

Estierra Terrain Model of the Grand Teton Mounts

Compass has new adjunct program called Estierra. Estierra is a program for modeling the terrain of the earth. It reads standard USGS Digital Elevation Model files (DEM’s) and converts them into three-dimensional models of the earth’s surface. These models can be colored, shaded, highlighted and overlaid with topographic maps or aerial photographs. This creates extremely realistic 3D images of the terrain. In addition, Estierra uses Microsoft’s DirectX technology that gives it the ability to do high-speed animations of the terrains. This means the terrains can be zoomed, panned and rotated in real-time. You can even fly over and through the terrain using a joystick or mouse. Go to the Estierra Web Page for complete information.

Free To Registered Compass Users

If you are a registered user of Compass, you are automatically registered for Estierra. Also comes on the Compass CD-Rom Package

Here is a model of the terrain around Lechuguilla Cave with a topographic map overlaying the surface. The canyon to the northwest is the Serpentine Bends. The cave appears along the lower right edge of the image. Terrains can be overlaid with geologic maps and aerial photographs with equally stunning effect.

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