3-D Fly Through and Quicktime VR
Visualization and Simulation
This project has used a variety of visualization tools to assist in better understanding both the data and the region. A variety of new technologies allow us to view our data in interesting ways from the laboratory when it is not possible to be in the field.
For example, we can "fly" through the study area and look at different GIS layers draped over the terrain. First we need a digital elevation model (DEM) showing the topography of the region. For this project this was generated from the French 1:25,000 scale topographic maps.
................. Digital Elevation Model of the region and SPOT image overlaid on a shaded relief image
Shown on the left above is the gray-scale DEM of the Arroux river valley. Click on the image for a larger view. Lower elevations along the river are shown in black, shading to white which represents the highest terrain in the region, including the site of the hillforts. We next created a shaded relief may that shows shadows and then combined the SPOT landuse landcover image over it. This is shown in the yellow graphic above right (which you can click on the view as a larger image).
Next we create a 3-D fly-through of the valley, which shows the region in three dimensions as we fly up the river. We can overlay any combination of GIS data layers in these.
For example, we can "fly" through the study area. This first shows the SPOT image, and then the Digital Elevation Model (DEM):
Click here for fly through
QTVR Virtual Reality
Other new capabilities allow us to view locations on our computers over the web using Quicktime Virtual Reality (QTVR). QTVR lets us pan and zoom interactively to see the actual view from given locations in the study area. This is very useful in determining the accuracy of Line of Sight GIS computations, for example.
The visualization below was created on the summit of the Celtic hillfort of Mt. Dardon you have seen in the images and maps above. You can put your mouse on the image and click, then drag your mouse to look left and right, up and down. You can also zoom in and out using the 'shift' and 'control' keys. You can see the commanding view this hillfort had of the surrounding terrain, and you can also see portions of the Celtic ramparts which have survived intact. The three stone crosses sit atop the ruined walls of a 9th Century Christian chapel that was excavated by our team in 1979. A red geodetic marker is also visible.
France1 QTVR 305 k
To view the Quicktime VR movie on your browser you will need a free plug-in available from Apple. The software is available for both Macintosh and Windows. The Apple site also has several other relevant QTVR examples.
Work is continuing in the use of QTVR and related techniques. We have made QTVR visualizations on Mt. Dardon where we created the Line-of-sight analysis discussed in the GIS section. Their accurate locations were computed with GPS.This has been used to quantify the ACTUAL visibility from these locations as compared to the LOS computations. Different DEMs and even different software packages (GRASS vs. Arc/Info) compute the LOS differently. Using QTVR assists us in developing better models.