Legend Files


Legend Files

A legend file may have any valid file name, as long as the file name root exactly matches that of the associated map file. Also the legend file must reside within the defined legend file directory. A unique legend file exists for each map or advisory.

In the case of a map, the legend defines how the map "fits" the geography which it covers. For example, it may be a smooth rectangular, north aligned fit, if the map has no calibration points and its skew angle is zero. A map with a rough or "warped" fit to the earth might require a large number of calibration points; while yet another map, on which north does not point upward, might require a skew angle to describe its angular departure from true north.

For advisories, the legend file defines the qualifier component of the advisory. That is, it defines what must happen in order to activate the advisory. For example, course, course variance, event ID, and the vehicle ID list are all qualification components of an advisory legend.

Note: If you want to disable a particular map, you can rename the map’s legend file. By renaming the file extension (Dallas.leg to Dallas.le), RASTRAC will no longer recognize the filename and it will not open the map (you must reboot RASTRAC after changing the filename). If you want to re-enable the map, just rename the map legend file back to the original filename.