We have recently acquired a project that is part of an existing structure that was built back in the 40’s. This project is requiring us to use the original datum that was used when it was built. Without going into too much detail the project requires us to use of NAD27 and the NGVD29 vertical datum.
I have noticed that TBC lists NAD27 as a recognized coordinate system but I’m having a difficult time figuring out where the vertical datum is or if it is even available. Thought I’d just get the question out there and and see if you might have any thoughts.
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Did you ever get a response for this? I am having same issues.
If all else is failing, you should be able to use a combination of epsg.org and epsg.io and manually add missing datums. It will help if you can find the EPSG identification for each datum.
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Parna,
I apologize for the late reply. We ended up using the NADCON (North American Datum Conversion Utility) to assist in the conversion to NAD27. We then had to add a vertical shift to match the large delta we had in elevations.
Here are a few screen shots to show what we did inside TBC:
This is the coordinate conversion narrative:
Keep in mind that our project is in Grid. No conversion was/is needed to get it to ground. We have to use a total-station on some portions of the project, so we do use a scale factor in those circumstances.
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