Based on a previous post on affine transformations of GIS data in PostGIS, I have put together a function that takes a table of control points and computes the affine transformation coefficients using the least squares code from GRASS. A nice tutorial by Dylan Beaudette on this is at: http://casoilresource.lawr.ucdavis.edu/drupal/node/433
At this point I would like some feed back on how this could be used. I envision a GIS package (say uDIG) would allow a user to select pairs of points and populate a table with a similar layout as ESRI's link table when georeferencing. A query would give the RMS error and similar query would return the table back with the residual errors. If the user were then happy with the values (after deleting poor matching points), a final query could then be made to the ST_Affine function to modify the geometry based on the control points. Comments? Bruce Rindahl _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
