I am having several issues when trying to perform a geographic coordinate system transform on reference files in ORD. We are working on a very large project in Philadelphia which is the NAD83 coordinate system using the NAVD88 vertical datum. All of our project files are using this datum. With this project, there is an existing base slab running along the entire corridor as well as a very large twin cell box sewer, both of which were designed and built in the late 60's/early 70's, thus the geographic used for the record plans for the base slab and box sewer is NAD27 using the NGVD29 vertical datum.
We want to show the existing base slab and box sewer in our plans so I created two models in the older record plan datums (NAD27/NGVD29) one for the base slab and one for the box sewer. We decided to build the models this way since we thought it would be easier to create the models off the record plan coordinates/elevations and then just to a geographic reprojection when we reference the files to get everything in to the project datum (NAD83/NAVD88). Both models are created and dont have any issues. The issues I am having arise when I try to cut cross-sections.
For the cross-sections, I started a new file with the geographic coordinate system set to the project datum (NAD83/NAVD88). I then referenced in the project baselines along which I will cut the cross-sections. The project baselines file was set up in the project datum (NAD83/NAVD88). I then reference in the both the base slab and box sewer files with the orientation set to "Geographic - Reprojected". When the files come in, the x and y reproject correctly, however the z does not (i.e. the z vales of points are the same when reprojected as in the the original NAD27/NGVD29 datum.
The other issue I have is that the reprojection apparently causes errors from the referenced base slab and box sewer models. See the attached error messages. This error ONLY happens when these are referenced using the geographic reprojection. If I reference them in with "Coincident World" set, I do not get the errors. I think these errors are also casing problems when cutting the cross-sections because the named view limits doe not seem to want to pick up the elements in the corridor causing the errors. For example, when generate the cross-section named views, the boundaries on some sections cut partway through the thickness of the base slab.
Has anyone else experienced these issues and knows how to resolve them? Thank you!
Carl Oberg, PE
I believe I figured out the vertical reprojection issue. In the coordinate system settings, there is and "Edit Reprojection Setting". In the reprojection settings, under the "Reference" tab, there is item for "Reproject Elevations" which by default is set to No. I changed this setting to Yes and re-referenced the reprojected files in and the vertical elevations get reprojected correctly. I am still getting the multiply error messages however.