Image Layers in the VTP software. You can add any number of image layers on each terrain, but since they are limited by the number of multi-texture units your graphics card has, the number displayed may be limited to 3.
To add an Image layer, edit the properties for your terrain. Under the Texture tab, under Image Layers, double-click to choose from a list of all the image files that are located in any GeoSpecific folder on your data path.
The image must be:
- Georeferenced. Specifically, it must have extents defined. An easy way to ensure this is to use GeoTIFF format, but you can also use other TIF or JPEG files as long as they have a World File which defines their extents.
- The same CRS (projection) as the terrain. Image layers will not be dynamically reprojected.
- Within the size limits of your graphics card. Modern 3D cards will support up to 8192* 8192. You can also use smaller images, e.g. 1024x1024, and rectangular images, e.g. 2048x512.
If you have an older card without OpenGL 2.0, the the image should also be:
- Power of 2 in each dimension. For example, 256x512 is supported, 300*711 is not.
Image layers are shown in the Layers Dialog. You can do these operations on an image layer:
- Remove: Remove the selected layer.
- Visible: Toggle whether the selected layer is visible.