It is always difficult when you have sets of different overlapping rasters to visualize properly. Rasters are usualy a full coverage and so two rasters(or more) on top of each other block the view on one of them. As historically ILWIS is oriented towards rasters I felt I had to offer more flexibility when displaying rasters. So what options do we have? Well basically three
- Transparency. Make one layer (partially) transparent so you can view the “lower” layer
- 3D Orientation. seperate the two layers in 3D space and view them there
- Time shift. Quickly blink between layers to inspect different layers
- Class maps may make some of their class fully transparent. In the legend one can deselect classes which than become fully transparent. You get than a picture like this
- A value range can become transparent. In the beta you already have the interactive representation (discussed in an earlier blog), in the internal version I have(2011-11-29) I have added two, related, extra options. The first one is directly through the tranparency form of a layer.
- In this you see a range of values(0-150) being indicated as being 100% transparent and the underlying polygon map becomes visible. Related to this is the “command-line” method. In the internal version each mapwindow has a commandline that is similar to the command line of the mainwindow, Similar, but not 100% equal. Calculated maps from that command line are automatically added to the mapwindow. It has one extra option. The ability to add a displayoptions parameter that describes how the added map should be rendered. One of the parameters in there is similar to the transparency in the form. Below is such a result( with the calc expression)