AutoCAD Civil 3D 2010 Video for Land Surveyors: Coordinate Systems
This video shows you how to setup the coordinate system in your AutoCAD Civil 3D 2010 Drawing and Survey Database.
The goal here is to make sure that the coordinate system in your AutoCAD Civil 3D 2010 (the same applies for older releases) Drawing agrees the coordinate system you're using in your Survey Database.
Out of the box, even when opening an Imperial Template, you may be surprised to find that the "Foot" definition is not what you may have expected. By default, the Imperial Template and the Survey Databases is set to use the International Foot (1 Foot=0.3048 Meters) for Imperial to Metric conversion.
It is up to you to change these settings to use the US Survey Foot (39.37 Inches per Meter) for Imperial to Metric conversions, if that is the appropriate Foot Definition that you should be using. Play the video below to learn more.
I hope that this video was helpful to you and that you now know how to setup your AutoCAD Civil 3D Drawing and Survey Database so that both are based in the same coordinate system. As I said in the video, there may be times when you purposely want to have your AutoCAD Civil 3D Drawing in one coordinate system and your Survey Database in another.
An example of this may be if your AutoCAD Civil 3D Drawing is in an assumed datum and your Survey Database is in State Plane Coordinate System (or the other way around) and you know how they relate by rotation and transformation calculations.
However, it could be disastrous, for example, if you did not recognize that you setup the drawing using US Survey Foot Imperial to Metric conversion but accidentally left the Survey Database with its default International Foot Imperial to Metric conversion. This is particularly true when applied to the generally large coordinate values assigned to State Plane Coordinate Systems.
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