I'm attempting to "create" a custom Coordinate System. My required coordinate system is a rotated and shifted (no scale difference) version of our local State Plane coordinate system. I copied the "seed.dty", updated MS_GEOCOORDINATE_USERLIBRARIES to point to the new .dty location, and opened Bentley Map (standalone). I then copied the appropriate State Plane definition into the newly created .dty file. Next, I added in the X and Y "shifts". I created two models - one with known points in the State Plane projection, and the other using my new GCS. After verifying the points I placed were in the correct location, I referenced in the model that had my "new" GCS to the State Plane model. I saw the points overlay at my new GCS origin, so I verified the "shaft" parameters worked. I then went back and added the rotation (which I'm assuming is to be input in radians) then opened up the State Plane model again. Now my GCS still is properly aligned at the origin, but the scale and rotation are NOT correct. I created an Excel spreadsheet using the Helmert formulas in the help file and verified the results against an internal coordinate converter, so I'm confident the "math" formulas are correct. However, the results I get from "snapping" on a point in the model DO NOT match up (excepts at the origin). I also see "scale" and "offset" parameters listed for the reference. I expected those to be zeros, and the transformation to handle all the reprojections.
In the image below, the blue (thin) line is in State Plane GCS, and the heavier green is my "local" data prorojected to the State Plance GCS
The scale difference I see is the same factor as is displayed in the "Scale" box on the Reference file dialog box. When I look at a "re-projected" model in plain MicroStation SS3, I don't see any values in the greyed out Scale/Rotation/Offset boxes like I do here. However, In plain SS3, I am seeing a "scale" difference (Survey Feet verses meters. When we set this up initially (in MicroStation SS2) our custom GCS was working fine. Now I'm seeing a scale issue in SS3, so I've gone to Bentley Map to "start over" and I can't get things to overlay as expected. Are there any issues/problems/changes between SS2 and SS3 and Bentley Map SS4?
Thanks,
Bruce Reeves
Sebastien Cote
Regards