[GRASS-user] category number incrementing when digitising

Moritz Lennert mlennert at club.worldonline.be
Fri Nov 18 05:19:34 EST 2011


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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