Wxpython - vector georectification fails at i.group

[rchirgwin]

Version: Grass 6.40RC5 Platform: OSX 10.5.8

When using the Python GUI to rectify a vector, georectification fails at i.group. The i.group module in the GUI is assuming that georectification is for rasters.

Steps:

1. Select "vector" at first screen (along with source map location and mapset).
2. At second screen, select "Create / Edit Group"
3. Give group a name
4. Click "Apply"
5. Result below:

Error in command execution i.group Execution failed: "i.group group=test" Details: Error: no input raster map(s) specified

Richard Chirgwin

[hamish]

as its i.* name suggests i.group et al were designed for rectifying imagery rasters, not vectors. vectors are a modern slap-on hack only present in the GUIs. thus a solution should be carefully considered, but could be as simple as a new group/$GRP/VREF file. This is really an issue for grass7 IMO and for 6.x now we'll just have to figure out some work-around.

Hamish

[cmbarton]

In both TclTk and wxPython, the georectification GUI uses GUI code to create a VREF file for vectors, and to parse the VREF file in the same way as is done for rasters.

Apparently, something has broken this functionality in the current version of the wxPython GUI. Unfortunately, I probably won't have time to look at it for a few weeks.

Michael

[harrikoo]

Unfortunately, this bug seems to be entering the next Debian Stable ("Wheezy"), as the current version in testing still has this bug: the "Georectify" tool cannot be used with vector maps, as it forces one to create an imagery group.

[neteler]

Bug confirmed for 6.4.svn (upcoming 6.4.3).

[mmetz]

Replying to neteler:

Bug confirmed for 6.4.svn (upcoming 6.4.3).

Groups don't support vectors, the current support in the georectifier GUI is a hack specific to the georectifier GUI. A workaround is to create a group with a raster map, then click on the button 'Add vector map to group...' and continue, but vector rectification will probably fail at a later stage. Note that vector rectification similar to raster rectification exists only in GRASS 7, not in GRASS 6. For GRASS 6, the solution would be to disable vector support in the georectifier GUI and implement v.group (or g.group supporting both raster and vector maps) in G7.

Markus M

[harrikoo]

Yes, it seems that the georectifier runs v.transform in the end, thus leaving the "rectified" map to the current location and mapset, not to the target location as one is made to expect. It is easy to move the new vector map directory to the desired lcation/mapset/vecto -directory.

All in all, the rectifier as it is in 6.4.2 is not useable; but it does contain working parts, and these could be used to implement a working solution.

[mmetz]

Replying to harrikoo:

All in all, the rectifier as it is in 6.4.2 is not useable; but it does contain working parts, and these could be used to implement a working solution.

What do you mean with not usable? It works fine for raster maps.

Markus M

[harrikoo]

Sorry, I meant unuseable for vector rectification; for raster maps it works well.

Harri K.

[martinl]

Still relevant.