Recreating real terrain from Google Earth

[Emx77]

Pat, I would like to thank you for realy useful information. During, last two days I have been trying to use all of above information in order to recreate small portion of terrain. Unfortunately, I haven't succeeded yet as I am probably doing something wrong.

Originally Posted by Patrick Proctor

Use the info function to get the grid transform angle. That angle will be in degrees, which you can convert to mils.

In MicroDem function "Map information" gives following:

True north at top of map
DEM native datum: WGS72
--------------------------------
Magnetic declination: 3.5°
UTM Grid declination: -1.2°

At the same time function "Horizontal Earth Curvature" provide:

Point: N43°46' 0.01" E18°58' 0.00"
Grid true angle: -1.56

I noticed that -1.2° (-21.3 mils) is some kind of average for whole map area, while -1.56 (-27,7 mils) is value for bottom left corner of map. Also, with function "UTM-grid true north declination" it is possible to get value for exact spot on map (for example -1.54). I hope that these are "grid transform angle" values you have mentioned before. If so, I presume that best measure is one obtained through "UTM-grid true north declination" for map area I want to recreate. Right?

Nevertheless, I tried all of mentioned values on my map but resulting AATF contour map doesn't match Google terrrain map and there is always some discrepancy. If I entered right coordinates, mils and m/s, could there be any other reason for this discrepancy? Different map projections maybe? Also I didn't change default 8-digit UTM values and Grid Zone Designators in Map Information Dialog (as I presume that is enough to put right long. and lat. coordinates).