Image Layering
(Layering has been turned off in this release due to a
registration problem)
Image Layering
Caution: The VTT will occasionally have difficulty in correctly registering images. Whenever image layering is used it is important to have enough overlap between images that a visual check can be made to verify that objects appearing in both images are registered correctly.
Image layering provides the ability to display multiple images, overlayed together,
registered within the same world coordinate system. When a new image is
loaded, if it can fit within the WCS of the current displayed image, the
new image is transformed so that it is displayed at the correct position,
size, and orientation within the larger image. In addition, each image
is contained within a Layer. There is a Layers window that shows all the
layers and lets the user adjust properties such as transparency of layers.
Catalogs are also represented as layers (one per catalog), with the added
ability of specifying the color of each individual catalog.
Layers Window
After you have loaded two images (or an image and two catalogs), you can
adjust the layers using the Layers window. Select the Layers options from
the ImageTools menu. Click on the layer you would like to adjust. The options
for that layer appear at the bottom of the screen. For an image layer you
can adjust the opacity, whether that layer is visible, and whether it is
on the top or bottom. For a catalog layer you can additionally adjust the
color that the catalog is displayed in. This can be handy when displaying
multiple catalogs that you need to differeniate.