Over the past, I took a course in GIS and later ArcMap. Before GIS, we did some rough methods using dot grids, polar planimeters, aerial photos, mirror stereoscopes, etc., manually. So learning GIS was a game changer in time and detail. I think each GIS course lasted several days to maybe a week. This exposure for most professionals in my office was enough to give a basic knowledge and some actually became fairly proficient. Most professionals in the natural resources field of study would benefit from these courses, and the instructors will sometimes help with questions. There were workbooks or manuals where self study may also be tried. One problem I have remember with GIS is you have to continue to use it on some regularity, or eventually you may need a refresher course or some help to get back up to functioning. There is a GIS routine or process that allows for change detection, so if you had land use classified for several aerial photos over a series of decades or years, the change detection helps to quantify the differences in land use categories through time, or you might want to know if the forests were changed to agriculture, urban, residential homes, roads, etc., or you might want to use this type change detection to help estimate with some substantial effort of course, landscape effects to sedimentation, runoff, water balance, ET, carbon sequestration, habitats, etc.
GIS and remote sensing techniques have opened up wide range of avenues for effective land use and land cover mapping. The remote sensing data combined with field survey data can provide a unique and hybrid database for optimal mapping of land use and land cover.