Getting Started
with VNS 3: Draping
Images on Terrain
Part 4A. Color Maps
1. Go to the File menu
and open the YNP project from the recent projects list.
This is the project we created in the last tutorial. Return the
Main camera to its default location. Open the Plan
Camera in the right view. Save the project as YNPCM.
2. Open the Database Editor and you'll see the YNP-100m DEM enabled,
the one we created for higher elevation viewpoints. The 10-meter
DEMs are disabled. We're looking at terrain near the western
border of Yellowstone National Park, just east of the town of
West Yellowstone, Montana. We're going to import a corrected
color satellite image of the Yellowstone area. The image will
be draped over the terrain as a Color Map.
3. Go to the Land Cover Task
Mode and double-click the Color Map category to create
a new Component.
4. Rename the Color Map Landsat.
We'll use the Image Object dropdown list to add the satellite
photo, but let's first copy the image to a convenient location
on the hard drive.
5. Open your file explorer of
choice to the VNS
3 DVD image folder.
Also find the YNP project folder on your hard drive.
6. Copy YNPLandsat.tif
to the YNP folder. The VNS project will remember where
this file was loaded from when we add it to the project. If we
load it from the DVD, VNS will try to find it there every time
the project is opened. Copying it to the project folder keeps
it with the project.
7. Back in the VNS Color Map Editor, expand the Image Object dropdown
list and add a New Image Object.
8. Navigate to the YNP
project folder and choose YNPLandsat.tif.
9. The image is a georeferenced
TIFF, or GeoTIFF, with a coordinate system different than the
one we're currently using. Make it the new default Coordinate
System.
10. After an image is imported,
its thumbnail normally appears in the thumbnail window. For larger
images handled by the Image Manager, a checkerboard stand-in
image appears.
11. Double-click the thumbnail
to open the Image
Object Library. Enable
Load Fast and click Apply to All. In the Current Applications
section you'll see that the image is associated with the UTM
12 - WGS 84 Coordinate System and Landsat Color Map.
12. The Geo Reference page
shows the Coordinate System and bounds.
13. This page also has tools
for georeferencing an image that isn't already georeferenced.
With Set Bounds in a View, you can click opposite corners
on the terrain where we want to place the image. Shift Bounds
in a View is very handy for making adjustments, something
even georeferenced images need sometimes. Snap to selected
DEMs is great when working with USGS Digital Orthophoto Quadrangles,
or DOQs, and USGS Digital Raster Graphics (DRGs).
14. The Image Manager
is automatically added by VNS when it senses the need. It tiles
the image at render time, allowing you to use very large images
that would normally be unrenderable because of their memory requirements.
Read more about it in the Interactive Reference Manual. Close the library.
15. Realtime views show the active
Landsat Color Map highlighted. Zoom back in the Plan
view to see the Color Map bounds.
16. Return to the Plan
Camera to its default position.
17. Let's add the Landsat Color
Map as a realtime view overlay. Open the Plan View Preferences to the Overlay/Gradient page
and check Ecosystem Map.
18. The Status window
will show Generate TexMaps as the overlay is generated.
19. When VNS is finished, the
Plan view will refresh with the overlay.
20. Repeat the process for the
Main view: popup menu, View Preferences, Overlay/Gradient,
and Ecosystem Map. There will be less delay generating
the image because it's already in memory. Image detail is a function
of terrain resolution. Higher resolution terrain will show more
detail in the overlay.
21. The Color Map is getting
in the way of our realtime views, so let's hide it. Go to the
View Preferences
Land Cover/Water page and deselect the Realtime Color
Maps box.
22. Select the other view to
switch to its preferences and deselect the Realtime Color
Maps box.
23. Render a Main camera
preview. All that's left is to create a camera path to fly us
across the terrain.
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