[Qgis-user] [Modeller] How to calculate area in the graphical modeler of QGIS

[Alexandre Neto]

Hello Igor,

I don't have qgis here to test, but...


If I remember well, you need to  change the parameter type from value to
precalculated value.

If not, try adding single quotes around the expression.

Good luck,

Alexandre Neto

A segunda, 30/01/2023, 19:06, Igor Oliveira Ribeiro <
igorgeoinformacao at gmail.com> escreveu:

> Hey Alexandre, thanks for your reply.
> See below
> [image: image.png]
>
> On Mon, Jan 30, 2023 at 10:51 AM Alexandre Neto <
> alexandre.neto at qcooperative.net> wrote:
>
>> Hello Igor,
>>
>> Can you please explain what settings you have used in the field
>> calculator dialog. A screenshot would be helpful.
>>
>> Alexandre Neto
>> User Support
>> alexandre.neto at qcooperative.net
>> www.qcooperative.net
>> [image: www.qcooperative.net] <http://www.qcooperative.net>
>>
>> Igor Oliveira Ribeiro via QGIS-User <qgis-user at lists.osgeo.org> escreveu
>> no dia segunda, 30/01/2023 à(s) 13:14:
>>
>>> Hi community,
>>> I need your help. I'm using QGIS 3.10.11 with Grass 7.8.4. I'm building
>>> a QGIS modeler and I want to calculate the area of an input polygon.
>>>
>>> So, my input polygon is a vector feature. I tried using a field
>>> calculator ($area) and Advanced Python Field Calculator (Field "Formula", I
>>> used "value = $geom.area() ).
>>>
>>> However, nothing is working. When I run the modeler, there is no error
>>> message. But, I'dont have the area calculated either.
>>>
>>> Thanks for your help.
>>>
>>> --
>>>
>>> See our last paper:  <https://doi.org/10.1016/j.envpol.2020.114029>
>>>
>>> Impact of biomass burning on a metropolitan area in the Amazon during
>>> the 2015 El Niño: The enhancement of carbon monoxide and levoglucosan
>>> concentrations. <https://doi.org/10.1016/j.envpol.2020.114029>
>>>
>>> Igor Oliveira Ribeiro
>>>
>>> Post-Doc on Regional Climate Change, Vulnerability, Impacts and
>>> Adaptation - Cuomo Foundation/UEA
>>>
>>> +55 92 98103 7136 | skype: igorflorestal
>>>
>>> Universidade do Estado do Amazonas | Instituto Nacional de Pesquisas da
>>> Amazônia
>>>
>>> Visite: www.geoescrita.com.br
>>>
>>> <https://www.linkedin.com/in/igoroliveiraribeiro/>
>>> <https://www.instagram.com/geoescrita/>
>>> <https://www.researchgate.net/profile/Igor_Oliveira_Ribeiro>
>>> <http://lattes.cnpq.br/3909691804095045>
>>> <https://orcid.org/0000-0002-3529-0525> <https://www.geoescrita.com.br/>
>>>
>>> Think globally, act locally!
>>> _______________________________________________
>>> QGIS-User mailing list
>>> QGIS-User at lists.osgeo.org
>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
>>>
>>
>>
>> --
>> Alexandre Neto
>> User Support
>> alexandre.neto at qcooperative.net
>> www.qcooperative.net
>> [image: www.qcooperative.net] <http://www.qcooperative.net>
>>
>
>
> --
>
> See our last paper:  <https://doi.org/10.1016/j.envpol.2020.114029>
>
> Impact of biomass burning on a metropolitan area in the Amazon during the
> 2015 El Niño: The enhancement of carbon monoxide and levoglucosan
> concentrations. <https://doi.org/10.1016/j.envpol.2020.114029>
>
> Igor Oliveira Ribeiro
>
> Post-Doc on Regional Climate Change, Vulnerability, Impacts and Adaptation
> - Cuomo Foundation/UEA
>
> +55 92 98103 7136 | skype: igorflorestal
>
> Universidade do Estado do Amazonas | Instituto Nacional de Pesquisas da
> Amazônia
>
> Visite: www.geoescrita.com.br
>
> <https://www.linkedin.com/in/igoroliveiraribeiro/>
> <https://www.instagram.com/geoescrita/>
> <https://www.researchgate.net/profile/Igor_Oliveira_Ribeiro>
> <http://lattes.cnpq.br/3909691804095045>
> <https://orcid.org/0000-0002-3529-0525> <https://www.geoescrita.com.br/>
>
> Think globally, act locally!
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20230130/2d7e7e44/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 33484 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20230130/2d7e7e44/attachment-0001.png>