KML with absolute elevation


We are trying to export a Sketchup model with Absolute elevation. However, SketchUp always outputs models with “relative to the ground” value. How can we address it?

When you geolocate a model, SketchUp places the model origin at the coordinates of the geolocation point. If you know the real elevation of that point, you can select all and move the model contents by that amount in the z (blue) direction. Be aware, however, that the model coordinates are “flat earth”. They won’t take the earth’s curvature into account.
For a model that covers a large extent, this will lead to gradually increasing height errors away from the model origin.

Also not clear from your topic title: do you realize that SketchUp does not import or export kml? It works with kmz archives that contain a collada (dae) rendition of the model.

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Thank you for your answer. We will try it.

KMZ is a zip KML, so it is the same thing. But we had challenges that all exports were relative to the surface, and in other systems, they ended up to be at the sea (ellipsoid/geoid) level.

Not so! This is a common misunderstanding. A kmz is a zip archive that can contain multiple files and folders. As exported by Google Earth, the contents are all kml. But as used by SketchUp it is mostly not kml.

Try unzipping a kmz file exported from SketchUp (you may have to change the extension from kmz to zip to get your zip app to recognize it). You will see that it is a multi-folder archive with the only kml content a small bit that gives the geolocation coordinates of the model origin. The actual model is in a .dae file in a nested folder.

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