docs:autocad:land_desktop:establishing_a_spatially_accurate_drawing [hartungdesign.net wiki]

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====== Autodesk Land Desktop: Establishing a Spatially Accurate Drawing ======
This procedure will create a drawing project that will be accurate with planar coordinates as well as spatial coordinates, such as Latitude/Longitude.

===== Prerequisites =====
  * a known point in the drawing, representing a Latitude/Longitude
  * rotation of true North, if not straight up
  * a local geodetic coordinate system, using the same units as your drawing

===== Scope =====
  * define a spatial coordinate system for the drawing coordinate system
  * allow a local coordinate system to be used, such as for surveying purposes
  * allow .shp files to be imported accurately

===== Procedure =====
(this will be shown after the project has been created, so that older files may be updated as well)
  - open an existing project
  - go to Map -> Tools -> Assign Global Coordinate System
  - select the appropriate coordinate system for the file, using the same units (Example: Category=USA,Arizona, Coordinate System=HARN(HPGN)Arizona State Planes, Central Zone, US Foot)
  - if you have objects in the drawing, you may need to move them now to match up with the coordinate system you just selected
    * tip: if you don't know the coordinates of the local system, but you do know the WGS84 Lat/Long, simply use the Map -> Tools -> Track Coordinates tool to digitize a point using WGS84 Lat/Long (or any other system); then move your objects to the new point
  - once your objects are positioned properly in the drawing, you may want to set up a custom Northing/Easting (such as for surveying)
    - Projects -> Drawing Setup -> Orientation tab
    - use the Base Point dialog to select a point on your drawing that will correspond to a Northing/Easting (entered on this same page)
    - you may also use the North Rotation to define another direction for North, rather than straight up
  - you should now be able to:
    * import/export survey points with a custom coordinate system
    * import/export ESRI .shp files accurately
    * digitize, locate, inquiry etc... any point on your drawing, with geodetic accuracy

===== Points of Confusion =====
  * the Autocad coordinate system (X,Y) will have to match up with the local coordinate system of the earth, such as 
HARN(HPGN)Arizona State Planes, Central Zone, US Foot
  * your points will NOT use the Autocad coordinate system (X,Y), but instead use a Northing/Easting as defined in your drawing setup orientation