The purpose of this wiki is to provide instructions to convert an existing GeoReferenced MicroStation drawing using cartesian coordinates (X, Y, Z) to non-projected, Latitude/Longitude GeoReferenced drawing with angular units.  It is assumed the Geographic Coordinate System (GCS) is assigned.

As an example, the original DGN is drawn using State Plane GCS of NY83-CF.  The storage units are US Survey Feet.  This drawing will be reprojected to use LL84 as the GCS with angular storage units.  LL83 is a commonly used GCS applicable anywhere in North America.

If a drawing is reprojected from one Lat/Long system to another, the process only requires that the new GCS be assigned and reprojected.  Same as if a drawing is reprojected from on Northing/Easting GCS to another.  If converting from Northing/Easting to Lat/Long, the complication of changing the storage units manually is required.

The basic procedure is to change the working units from Distance to Angular and then reproject the drawing.  The steps are.

1. From the menu: Settings > Design File.  In the Design File Settings dialog, select the Working Units category.
2. In  the Advanced Settings click the Edit button.  Read, understand and OK the Alert box with the warning.
3. Change the Unit Type from Distance to Angular (Latitude/Longitude).  Note that the resolution can be changed to a larger value of, for example, 100,000,000 to provide better accuracy measuring and placing features with precision input.  This can be done without affecting the size the elements after the reprojection is done.
4. Click OK to complete the change from Distance to Angular storage units.  OK the changes to the Design File Settings dialog.
5. With the storage units changed the new GCS can be applied and the drawing permanenty reprojected.  From the MicroStation menu: Tools > Geographic > Select Geographic Coordinate System.
6. Select the LL83, or other Lat/Long GCS from the Library, Geographic (latitude, longitude), North America category.
7. Click OK to apply the selected GCS.
8. Select the Reproject the data.... option and click OK.  All elements in the drawing are reprojected to the new GCS.
9. Use the fit view tool to see the reprojected data.

You should verify the results by attaching the original drawing as a reference using the "geographic reprojected" orientation.  They should align.  Zoom in and place a very small element to verify the accuracy of precision input.

Also see these wikis

Convert Lat/Long in Degrees to Northing/Easting in Distance

Geo-Coordination With MicroStation

Assigning A Geographic Coordinate System