[GRASS-user] category number incrementing when digitising

Shane Litherland litherland-farm at bigpond.com
Sun Nov 20 09:51:44 EST 2011

Hi Moritz et al,

Thanks for your patient description. I have been using cats and tables
for a while now, and think I understand enough about how they work, your
explanation seems similar to what I'd read in the GRASS docs.

My concern here is not how to use them, but that the check/list boxes in
the dialog appear to increment the cat numbers without them actually
being used. e.g. If I click on 'next to use' in the listbox ten times,
the cat that will be used next goes from 320 to 330, before I have
digitised anything to even give a cat to.

A couple of other odd things like this in wx dialogs/gui seem to have
come down to what version of wx/python/GRASS is being run together, so I
was wondering if anyone else can repeat this event in their dialog, and
if not, why (maybe newer wx/python?)

Too late at night for me to dig up my system specs... tonight got wasted
with other dramas on GRASS and a bunch of lost data... but if you want
them, I can get them


On Fri, 2011-11-18 at 11:19 +0100, Moritz Lennert wrote:
> On 16/11/11 07:12, Shane Litherland wrote:
> > Hi all,
> >
> > 6.4.2RC1 on ubuntu 10.04.3, using wxgui
> >
> > when digitising new vector, in 'digitisation settings' on 'attributes'
> > tab, I can play around with settings to add record to table, auto or
> > manual cat etc.
> >
> > Noted that when cat mode is 'next to use' clicking the checkbox on/off
> > for 'add new record into table', the number keeps going up by one for
> > each click. same happens for the listbox for category mode if i keep
> > clicking on the 'next to use'
> Assigning category numbers to a geometrical object is independent from 
> the fact whether you add a record to a table or not. Category numbers 
> are identifiers you can assign to objects. If you wish you can link a 
> specific layer to a table and then those objects whose category number 
> appears in a specified key column in that table have attribute 
> information in the table, others don't.
> So, if you use 'next to use' mode, but check off 'add new record into 
> table', you assign a category value to the objects you will digitize, 
> but no corresponding entry is added to the category table. This can be 
> very useful when all you need is categories and not other attributes 
> (e.g. you use specific integer codes for land use classes and just 
> assign each polygon the relevant land use class code as category value 
> without creating an attribute table).
> I'm not sure, but I have the feeling that the above explanation might 
> also respond to all your other issues.
> Moritz

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