GCPs with relitive/wildcard coords

[jrp]

Related to http://www.agisoft.com/forum/index.php?topic=4719.0

Sometimes a GCP position is only known as a position relative to another GCP and sometimes without a full 3 coordinates known.

examples could include:

2 arbitrary points with a plumb bob or other hanging string between them;

intersection of an arbitrary shaped pool of water with objects;

2 arbitrary points known to be a certain compass bearing from each other (but at different unknown altitudes);

a point known to be a certain distance above the floor of a room, but it's position otherwise unknown.

Scale bar support is a special case of the above. GCP is maybe the wrong concept here, but you get the idea.

Note that entering 2 GCPs with fully fixed locations does not work at all, and has no effect on the location or orientation of the model -- this may actually be a bug -- see link for more details.

[Alexey Pasumansky]

Hello jrp,

The coordinate information from two points only is not sufficient to set up the coordinate system due to the rotational degree of freedom around the vector connecting two points.
So for the coordinate system definition you'll need three points, even, if the positions of two of them are known relatively to the third point.

To use special cases for these purposes  I can suggest to use custom Python scripts, as implementation of multiple different options in GUI doesn't seem reasonable, as each case may be necessary only for one user.
So if you have some custom requests, you can post a topic in Python scripting section or send an e-mail to support@agisoft.com with the description of the case and desired functionality and we'll assist you with the custom scripts.