[GRASS-dev] Re: [GRASS-user] Re: nc_spm_08 - 'cat' double

[Markus Metz]

Hamish wrote:
> Martin wrote:
>   
>> in GRASS 7 we can support as key column also non-integer
>> columns,
>>     
>
>
> "just because we can, doesn't mean we should" ...
>   
+1

The key column is used to link attributes to vector features through the 
category number assigned to vector features. Category numbers are stored 
both in the coor and in the cidx file as integer, changing that would 
break forward/backward compatibility completely. Unless there are huge 
advantages of cat values being double instead of integer, I would 
suggest not to rewrite substantial parts of the vector libs and many 
vector modules in order to support cat values as double (or char* or 
whatever).

Markus M