[GRASS-user] Null values in attribute table get converted to 0 (zero) during v.to.rast

[Markus Metz]

On Tue, Oct 29, 2019 at 7:40 PM Veronica Andreo <veroandreo at gmail.com>
wrote:
>
> Hi Daniel,
>
> I agree that if there's a NULL in the column, there should be NULL in the
resulting raster. I suggest to open a ticket here:
https://trac.osgeo.org/grass/

that would require to change db_select_CatValArray on library level here
https://github.com/OSGeo/grass/blob/master/lib/db/dbmi_client/select.c#L368
and here
https://github.com/OSGeo/grass/blob/master/lib/db/dbmi_client/select.c#L375

I can't estimate the side effects of any changes, this is a widely used
function, thus no easy fix. Please open a ticket.

Markus M

>
> Cheers,
> Vero
>
> El jue., 24 oct. 2019 a las 14:40, Daniel Victoria (<
daniel.victoria at gmail.com>) escribió:
>>
>> Hi list,
>>
>> I have a vector polygon map that I'm converting to raster. The attribute
column that I process has some empty rows (no data / null). When I run
v.to.rast, these empty rows become 0 (zero) on my resulting raster map.
>>
>> Shouldn't v.to.rast respect the empty attribute table and create null
values for those polygons?
>>
>> For now I'll use r.null to fix this problem. But what if 0 is a valid
value?
>>
>> Cheers
>> Daniel
>>
>> PS - Running Grass 7.6.1 on Ubuntu
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