Composite files allow the user to group a selection of common files into one file. These files can either be displayed all at once, as though they were a single layer (Imagery Set or Binary Grids), or used as an Image Toggle.
Allows multiple image layers (or binary grids) to be displayed, controlled and interrogated as if they were a single file. Generally, composite files are used to group tiled aerial photography/grids into a more manageable single reference file.
Open - Open an existing composite file for editing
Add - Add a layer to an existing composite layer. It is good practice to ensure that all layers in a composite file have had their projection set. If no composite file has been loaded, you will be prompted to create a new composite layer:
Lift/Lower - Change the display order of a layer in the list. Layers at the top of the list are drawn first, meaning in any areas of overlap you will see the layer that is lower in the list.
Delete - Remove the selected layer from the composite file
Cancel - Closes the form without saving the composite image file
Save - Saves any changes to the composite layer
Save reference to layers within the composite file as relative or full paths. Relative paths are relative the to composite layer and are generally preferred as it makes your projects more portable.
For image sets only (*.aps), redundancy can be incorporated into a project using an Image Server (*.imgsvr) by creating a composite file (*.aps) referring to both the image server and a set of file based aerial photography. If the WMS is unavailable/unreachable, imagery will automatically fall-back to using the file-based imagery. In such a setup, the first file in the *.aps composite layer must be an image server (*.imgsvr). The remaining files should be disk based image files. The tick-box will ensure that the composite file layer order is correct. Only one image server can be used. If multiple image servers are added to a composite layer they will all be displayed.
Image toggle layers are designed to allow quick toggling of background imagery. By establishing a list of layers, the end user is able to select a layer from the list to use as their background imagery.
The image layers used in an image toggle layer can include an Air Photo Set (*.aps) composite layer. A common example would be to provide a toggle between aerial imagery and street maps.
Note that an image toggle layer can accommodate multiple projections (for example, your aerial imagery may be in GDA94 MGA Zone 56 but the Open Street Map image server will likely be in Web Mercator).
This means that the following rules must be followed:
•all layers in the image toggle must have their projection specified
•all views that the image toggle is included in must have the view projection specified
Image toggle layers are setup in the same way as standard composite files, above, except that for each layer in the list, a display label must be specified. This is what the user sees in the interface as they toggle between images. A tutorial on setting up an image toggle is available here.
Example image toggle between aerials and street map: