[GRASS-dev] v.transform dysfunctional in 6.4.3.svn

[Benjamin Ducke]

On Thu, Oct 25, 2012, at 17:23, Markus Metz wrote:
> On Thu, Oct 25, 2012 at 12:06 PM, Benjamin Ducke <benducke at fastmail.fm>

{SNIP}

> 
> This table option is a bit strange. Looking at the code, it is not
> clear which column is used as key column to select the appropriate
> transformation parameters for a given point, probably a column named
> "cat". Furthermore, there are no options to define database and
> driver. In GRASS 7, I have removed the table option, the table is here
> selected through the layer option, which is also used to select the
> appropriate category for a given point, also in GRASS 6.
> 
> I have changed the behaviour of v.transform in r53553/4 such that the
> table option can be safely ignored. Individual transformation
> parameters stored in an attribute table can be used with the 'layer'
> and 'columns' option. In theory the table option is still recognized.
> Is this OK?

Sounds good to me.

Best,

Ben

> 
> Markus M
> 
> >
> > Anyhow, without the "table=" option set, v.transform crashes
> > due to this block of code on line 166 of trans_digit.c:
> >
> > if (field > 0) {
> >         db_close_database_shutdown_driver(driver);
> >         G_free((void *)trans_params);
> > }
> >
> > The problem here is that "driver" never gets malloc'd,
> > unless the "table=" option is given (look at lines
> > 53 and following in trans_digit.c).
> >
> > With the "table=" option given, there are still illegal
> > write operations. Valgrind points to lines 88, 126 and
> > 136 of trans_digit.c as culprits. These will make
> > v.transform crash or not -- depending on your luck.
> >
> > Cheers,
> >
> > Ben
> >
> > --
> > Benjamin Ducke
> > {*} Geospatial Consultant
> > {*} GIS Developer
> >
> >   benducke AT fastmail.fm
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