Knowledge Base

Category: AutoCAD
Topic ID: 203
Title: Map R2/R3: Converting Drawing Coordinate Systems
Created: 0000-00-00Last modified: 0000-00-00

This procedure will explain how to convert drawings from one coordinate system to another using AutoCAD Map R2 or R3. Follow the outline for both versions, when a difference exists between the two follow the instructions for your particular version.

This example will convert a drawing in WV South 27 to WV South 83.  The process will be the same regardless of the original or target system.  We will refer to the original drawing as ORIGINAL.DWG and the new drawing as TARGET.DWG, with the obvious intention of preserving the original drawing.  At your discretion you can overwrite ORIGINAL.DWG with the contents of TARGET.DWG.

Assigning the systems

For Map to successfully produce the conversion, it needs to be told the coordinate system of the riginal and target drawings.

For MapR2:

MapR2 Assign Dialog

  1. Start AutoCAD Map with a new, empty drawing.  Do not load the drawing.
  2. From the Map pulldown, choose Map Tools, then Assign Global Coordinate System.
  3. Set the radio button to 'To Current Work Session'.
  4. Choose the Codes button in the center of the dialog to bring up the 'Global Coordinate Systems dialog as shown below.
  5. Pull down the categories pulldown and choose (in this example) USA, West Virginia.
  6. From the list of 'Available Coordinate Systems', choose NAD27 West Virginia State Planes South, US Foot.
  7. The CS Code field should now read: WV-S, which we will assign to the current (target) drawing.
  8. Choose OK to exit the dialog and make this assignment.
  9. Press the Enter key at the command prompt to repeat the ADESETCRDSYS command.
  10. Set the radio button to 'To Selected Source Drawings'.
  11. Choose the Drawings button, select the desired drawing (ORIGINAL.DWG), add it to the selected drawings and choose OK.  The bottom of the assignment dialog should say 1 Drawing(s) Selected.
  12. Choose the Codes button in the center of the dialog to bring up the 'Global Coordinate Systems dialog.
  13. If necessary, pull down the categories pulldown and choose USA, West Virginia.
  14. From the list of 'Available Coordinate Systems', choose NAD83 West Virginia State Planes South, US Foot.
  15. The CS Code field should now read: WV83-SF, which we will assign to the (ORIGINAL.DWG) drawing on disk.
  16. Choose OK to exit the dialog and make this assignment.  This may take a few seconds depending on the size of the drawing.

Global Coordinate Systems

For MapR3:

MapR3 Assign Dialog

  1. Start AutoCAD Map with a new, empty drawing.  Do not load the drawing.
  2. From the Map pulldown, choose Map Tools, then Assign Global Coordinate System.
  3. Choose the Codes button in the 'Current Work Session' section to bring up the 'Global Coordinate Systems dialog as shown above.
  4. Pull down the categories pulldown and choose (in this example) USA, West Virginia.
  5. From the list of 'Available Coordinate Systems', choose NAD27 West Virginia State Planes South, US Foot.
  6. The top edit field should now read: WV-S, which we will assign to the current (target) drawing.
  7. In the middle 'Source Drawings' section, choose the Drawings button, select the desired drawing (ORIGINAL.DWG), add it to the selected drawings and choose OK.  The middle the assignment dialog should say Number of selected source Drawings: 1.
  8. Choose the Codes button in the center of the dialog to bring up the 'Global Coordinate Systems dialog.
  9. If necessary, pull down the categories pulldown and choose USA, West Virginia.
  10. From the list of 'Available Coordinate Systems', choose NAD83 West Virginia State Planes South, US Foot.
  11. The CS Code field should now read: WV83-SF, which we will assign to the (ORIGINAL.DWG) drawing on disk.
  12. Choose OK to exit the dialog and make both assignments.  This may take a few seconds depending on the size of the drawing.

At this point we have assigned coordinate systems to both drawings and are ready to proceed to querying the objects into the current (target) drawing.

Attaching the Source Drawing

At this point we have informed Map about what coordinate system the ORIGINAL.DWG is in, but have not attached it as a source drawing.

Define/Modify Drawing Set Dialog

  1. From the Map pulldown, choose Drawings, Define/Modify Drawing Set.
  2. Choose the Attach button, select, add, and open the ORIGINAL.DWG.
  3. The dialog should now show your drawing attached and active, then choose OK.

Querying the Objects

AutoCAD Map does the transformation as drawing objects are being queried into the current drawing.  So the next step is to setup a simple query to import all of the objects.

  1. From the Map pulldown, choose Query, Define Query.
  2. Choose the Location button in the lower left.
  3. In the 'Location Condition' dialog, 'All' is the default so simply choose OK.
  4. In the center of the 'Define Query' dialog, set the query mode to 'Draw'.
  5. Choose the Execute Query button to query in the objects.

wpe6.jpg (36507 bytes)

Finishing Up

The geometry is now available in the current drawing in its translated form.   Simply do a zoom extents to display the geometry, then save the drawing.

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