[GRASS5] v.out.ogr question

[Markus Neteler]

On Thu, Mar 18, 2004 at 10:59:53AM +0100, Otto Dassau wrote:
> Radim Blazek schrieb:
> > 
> > On Wednesday 17 March 2004 18:23, Markus Neteler wrote:
> > > On Fri, Mar 12, 2004 at 05:58:40PM +0100, Otto Dassau wrote:
> > > > Hi,
> > > >
> > > > I used the module v.out.ogr in GRASS5.7 to export polygons but missed
> > > >
> > > > the parameter 'type=area'. The result was a warning:
> > > > > WARNING: Requested types: points and lines, but (additionally) areas
> > > > > found. Check 'type' parameter.
> > > > > 3426 features written
> > > > > WARNING: 3426 features without category written
> > > >
> > > > but the map was also exported with lines instead of areas. I don't
> > > > understand why the module explains a mistake but still exports
> > > > the data. Wouldn't it make more sense to simply stop after warning,
> > > > so the user has to add/modify the missing parameter?
> > >
> > > Otto,
> > >
> > > I have made a test with a map containing a single area:
> > >
> > > v.info ammprv | grep Number
> > >
> > >  |   Number of points:       0               Number of areas:      1     |
> > >  |   Number of lines:        0               Number of islands:    1     |
> > >  |   Number of boundaries:   1               Number of faces:      0     |
> > >  |   Number of centroids:    1               Number of kernels:    0     |
> > >  |   Number of dblinks:      1                                           |
> > >
> > > GRASS 5.7.-cvs:~/test > v.out.ogr ammprv dsn=ammprv layer=ammprv
> > > WARNING: Requested types: points and lines, but (additionally) areas found.
> > >          Check 'type' parameter.
> > > 1 features written
> > > WARNING: 1 features without category written
> > >
> > > -> Strange: I would expect 0 features written.
> > 
> > Why strange? Requested type is 'line,boundary' (default) and there is 1 boundary
> > in ammprv and that boundary is exported.
> 
> Hi Radim, 
> 
> I simply think it would be nice, if v.out.ogr doesn't export any data,
> as long as 
> the parameter 'type' is not set correctly. This would just make sure,
> that the user 
> really gets what he intends. I know it is not an error, more a whish and
> maybe also too petty.

I have modified v.out.ogr messages to catch all cases. Now it always
prints a message if vector types are present but not requested for
export.

Examples:

#---------------- export of Lines map with wrong type parameter:
v.out.ogr viapri dsn=viapri layer=viapri type=area
WARNING: 2003 Line(s) found, but not requested to be exported. Verify
         'type' parameter.
0 features written

#---------------- export of Lines map with default settings:
v.out.ogr viapri dsn=ammprv layer=viapri
2003 features written

#---------------- export of Points map with  wrong type parameter:
v.out.ogr coords_cea dsn=ammprv layer=coords_cea
WARNING: 18 Point(s) found, but not requested to be exported. Verify 'type'
         parameter.
0 features written

#---------------- export of Points map with correct type parameter:
v.out.ogr coords_cea dsn=ammprv layer=coords_cea type=point
18 features written

Hope it's better now. Suggestions after testing welcome.

Markus