Difficulties with datums while importing Esri i3s into ArcGIS Earth

RE: Difficulties with datums while importing Esri i3s into ArcGIS Earth

Peter Sawall — Mon, 24 Apr 2017 13:42:41 GMT

The scan is aerial LiDAR (LAS), which I colorized, clipped, and converted to E57. I can email you a link to the file. Before updating to the most recent version of CC, I had been able to make a full reconstruction from the aerial survey, so I'm wondering what has changed to make it no longer work.

RE: Difficulties with datums while importing Esri i3s into ArcGIS Earth

Pierre Diebolt — Mon, 24 Apr 2017 13:15:20 GMT

Interesting, are you trying to import a Static or a mobile point cloud ?
Is there a possibility that you share your point cloud - or a part of it - with us? So we can see what's going wrong.
Note that if this is a mobile scan, the trajectory must have the same SRS than your point cloud.

Pierre

RE: Difficulties with datums while importing Esri i3s into ArcGIS Earth

Peter Sawall — Mon, 24 Apr 2017 12:41:16 GMT

Thank you Pierre,

Now that I've updated to the most recent version, I am able to select the proper spatial reference when bringing in my data. However, when I import a point cloud I now get an error specifying, "Failed to import point cloud files", with the reason, "Failed to setup SRS transformation". This is odd, as I was only specifying the input coordinate system (UTM + NAVD88).

RE: Difficulties with datums while importing Esri i3s into ArcGIS Earth

Pierre Diebolt — Mon, 24 Apr 2017 09:12:59 GMT

Hi Peter,

Sorry this is my fault, I forgot to mention that the NAVD88 vertical datum is available in the latest ContextCapture version only: Build 04.04.05.33.

Please go to the Bentley software download page and update your version.

Pierre

RE: Difficulties with datums while importing Esri i3s into ArcGIS Earth

Peter Sawall — Fri, 21 Apr 2017 17:56:13 GMT

All of the coordinate systems were directly specified. However, my version of ContextCapture only currently provides two vertical datums by default: EGM96 geoid height and NGF-IGN69 height (French National Vertical Datum). As such, CC has no vertical datum transformation information for NAVD88 exists within the program.

On pages 131-132 of the manual it specifies, "Some spatial reference systems use external dependencies which, prior to their use, must be installed in the "data\gdal" subdirectory of ContextCapture installation directory. For instance, a spatial reference system with a custom vertical coordinate system may use a GTX grid to approximate the geoid."

Does this mean I should just copy additional .gtx files into that subdirectory? Do I also need to import grid transformation files? If so, what format should I use?

RE: Difficulties with datums while importing Esri i3s into ArcGIS Earth

Pierre Diebolt — Fri, 21 Apr 2017 12:39:25 GMT

Hi Peter,

If you observe such vertical shift there is a chance it is also the case in ContextCapture. First can you make sure that you are using the appropriate geoid NAV88 when you import your data ? Also it is possible that ContextCapture support that altimetric grid in "feet" instead of "meters", can you see if it is better when you change your altitude values so to be based as feet instead ?

Regards
Pierre