Back to the original post; here is another thought. Still thinking of "worse case scenario", if you have a compass along with the map (as some said they just use the map), you could tell how many degrees S or SW of whatever large landmark there is. If on the phone with SAR or park ranger, etc, it would be a lot easier to say, "we are ___ degrees NE of ____ peak or Mt." Then, "we are on the part of the trail where the big turn is."