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Garfield
2012-01-27, 04:50 PM
I am new to creating surfaces in c3d with Google Earth (GE). My coordinates are correctly set (NAD83 Oregon State Planes (Polyconic), North Zone, Intn'l Foot) and my surfaces come out beautiful except for one thing - where the actual survey and google earth may differ by a few feet, c3d is off by more than a hundred. For example: The actual contours range in elevation from 184' to 196'. In panning GE the elevations range from 180' to 200'. In C3d, however, they range from 55' to 61'. What's up with that?

mjfarrell
2012-01-27, 05:41 PM
I am new to creating surfaces in c3d with Google Earth (GE). My coordinates are correctly set (NAD83 Oregon State Planes (Polyconic), North Zone, Intn'l Foot) and my surfaces come out beautiful except for one thing - where the actual survey and google earth may differ by a few feet, c3d is off by more than a hundred. For example: The actual contours range in elevation from 184' to 196'. In panning GE the elevations range from 180' to 200'. In C3d, however, they range from 55' to 61'. What's up with that?

So when you run the command:

Command: _AeccCreateImportGESurface
DWG Coordinate System: NAD83 Oregon State Planes (Polyconic), South Zone, US
Foot
Use coordinate system for surface location or [Identify] <coordinate system>:

Do you use the Coordinate system?

Is the drawing in Feet or Meters? As there appears to be a conversion issue happening.

Notice: 55 * 3.2808399 = 180.446195

AND 61 * 3.2808399 = 200.131234


Can I have your data to experiment with?

I'm happy to have a look at it.

mjfarrell
2012-01-27, 05:58 PM
OK, I just ran a couple of experiments...

IF you set your drawing settings as shown in the attached the surface will come in correctly

You my then need to Export the surface to XML

Set the units back to feet, and reimport to have the data convert from metters to feet correctly.

Garfield
2012-01-27, 09:44 PM
Thank you for your help - my drawing was set to meters. Once I changed it to feet my surface appeared correctly.