Rasing a topographic survey from NGVD 1929 to NAVD 1988

[surveyor5280]

I am trying to adjust (raise) a very intensive topographic survey from NGVD 1929 to NAVD 1988.

I know how to raise the surface and I know how to adjust the datum of the points.

Does anyone know how to raise all the breaklines used to develop the surface as well? 

This would include survey figures, feature lines and 3d polylines.

I want to raise them all by an equal amount.

Thanks in advance.

[g_k50]

First you have to know the dimension you want to move the breaklines.

Then look at the breaklines from the side, like at ground level, select all the lines and nothing else that you don't want moved.

Then move command, from 0,0,0 to the dimension you want to move, 0,0,100 would be 100 feet straight up.

[surveyor5280]

Thanks for your reply, but:

You can move only 3d polylines in that manner.

Survey figures and featurelines cannot be moved that way.

I need to know how to change the eleveations on all threee types.

[IanMcClain]

Survey figures are tied to the survey database and must be adjusted via the Survey>Translate Survey Database command (or right click on the survey database in the Survey Toolspace tab).

I am not sure about featurelines and 3d polylines, but I think you can raise them with the move command as g_k50 describes.

Featurelines would probably have to be edited manually. Or you could make them into survey figures and adjust them with the rest of the survey data.

[Joe-Bouza]

I don't know about survey figure but FL can definately be raised or lowers a delt with the move command

move all 0,0,0  0,0,1.02

[ericcollins6932]

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@surveyor5280 wrote:
I want to raise them all by an equal amount.

Thanks in advance.

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Are you sure the shift from NGVD1929 to NAVD1988 is a simple bulk shift? I'd look a little harder into that as I doubt that it would be so simple.

[AllenJessup]

Select all the Featurelines you want to affect, right click, select Raise/Lower. Command line: RaiseLowerFeatures

Allen

[AllenJessup]

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ericcollins6932 wrote:

Are you sure the shift from NGVD1929 to NAVD1988 is a simple bulk shift? I'd look a little harder into that as I doubt that it would be so simple.

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You're right Eric. It's not that simple. It may be adequate for the project goals to simply bump the surface. But it doesn't end up in true NAVD88.
 

The only way I've found is to start from scratch with a point file, run it through Corpscon and reimport them. Of course doing this late in a project can cause a lot of rework. So if the project doesn't have to be in a completely accurate vertical datum. A move may be acceptable but doesn't make it NAVD88.

Allen

[dgordon]

it is very important to either edit the datum or move the defining objects only. Do not do both or you will get very inaccurate results.