For our ContextCapture projects we have two customers. One customer needs Nad83(2011) NCSP NAVD88 Geoid 18 (xyz units us survey foot), the other customer needs Local Space Rectangular. The difference between the two SRS's is normally a scale factor. Knowing that the Surveyed Ground Control measurements in a photo is independent of the SRS. In Photogrammetry we historically called these plate measurements and they were in mm and local to each individual image. I have read about the BlockExchange format and that it can store these measurements. I need some help understanding how I can update the SRS and Surveyed Ground Control XYZ values.
For example lets say I have completed Block_1 and all needed productions have been processed. Would I Export Block_1 using the BlockExchange format? But now how do I edit the .xml to update the SRS and Surveyed Ground Controls XYZ values? I have the Local Space Rectangular Survey Ground Control values is a .csv and have yet to successfully, using WKT defined the Local Space Rectangular SRS with units of us survey foot.
I also see, with the upcoming datum/SRS change to NATREF and NAPGD a time where I will need to output both us survey feet and then also international feet.
Comments and Help on how I should approach the above issues would be appreciated.
P.S. My current solution is to run the whole process twice (including the measuring of the Surveyed Ground Control) very inefficient knowing in other Photogrammetry software that updating the Surveyed Ground Control from a .csv is very easy. There is a big difference between Importing vs Updating Surveyed Ground Control, same is true for the Exterior Orientation. And while I am at it why is there not a way to change the weights on all Surveyed Ground Control in bulk. Changing them one at a time is not efficient.
How do you apply the scale factor? Is it Helmert or Affine transform?
Oto,
To keep this focused, all I am looking for is a way to "update" the Surveyed Ground Control that was imported into CC with a revised set of the same Surveyed Ground Control points, they have had a scale factor applied for the ground to grid conversion. If there is no way to "update" the imported Surveyed Ground Control then I have to run the project twice and measure the Surveyed Control twice. I am looking into the BlocksExchange.xml to see if , using python i can script the solution I need.
When exporting GCPs there is an option to specify SRS. Internally Contextcapture uses ECEF coordinates so SRS is set only for exports. How do you specify Local Space Rectangular?
Marc Swartz said:why is there not a way to change the weights on all Surveyed Ground Control in bulk
Not only weights but also not possible to change to checkpoints in bulk.