Window X, Y Channels

Oasis montaj enables you to mask the X and Y channels to an area defined by a polygonal mask file. This enables all map-based processing that follows to only use the data within the defined region.

A copy of the original X and Y channels are saved to channels "__X" and "__Y" (if they do not already exist). Subsequent windowing operations will use these channels as the source channels.

Polygons are ASCII files with default extension .ply. A polygon file contains a list of X,Y coordinates that define one or more polygons. The file may contain any number of polygons, and each polygon may have any number of vertices. The first and last points in each polygon are assumed to connect. If the file will contain more than one polygon, each polygon must start with a line 'poly #' ('p' or 'P' in column 1). Comment lines are indicated by a '/' in column 1.

Clip polygon files may also be generated interactively by using the digitising tools in the Map Tools menu.