Accuracy of topographic data

Does anyone have any knowledge or opinion as to the accuracy of the topographical info available through the geolocation feature? Source? (Does Digital Globe use USGS?)

I ask because often the contour lines on a prepared civil plan often don’t match the contour lines that can be generated from the geolocated terrain map that Sketchup downloads.

Just curious…


If the civil plan was created from a local on-the-ground survey, I would expect it to be different from the other sources. It would be normal to expect the local on-the-ground survey to be more accurate although I’ve had experience with surveys that weren’t correct, too.

Yea, I have found, about often as not, that the retaining wall design height criteria to be a little short of actual site conditions. Which is what prompted the question. I’m doing a “proof of concept” portion of a project for a builder and, using the in sketchup geo data, the wall designs are a couple feet short. Their survey data may be more accurate, but modeling their civil plan wasn’t part of the work scope.

Thanks for weighing in, Dave!


I have found that in my area the terrain data, while OK, seems to be a bit averaged out.

The only resource to give you accurate topography of a site currently is to get a surveyor on the property. Many of those USGS maps available are +/- 10’-0" which is completely inadequate for accurately designing a structure.

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+/- 10’! Holy smokes, that’s not too useful now, is it?

Thanks Nick!

Those satellites are a fair way up in the sky after all. :neutral_face: