[QGIS-Developer] Calculate area/perimtere/length of polygon/line while editing

Tue Mar 11 09:37:45 PDT 2025

Thanks.  That works.   But looks like it only works when initially drawing the polygon as opposed to also working when editing an existing polygon.  I have a similar tool to this that shows the area when drawing, just trying to figure out how to get it to work when editing an existing polygon.  I was hoping to build on my own tool if there was an easy what to get a hold of some other signal that gets fired while editing.

From: Sylvain Théry <sylvain.thery at cnrs.fr> 
Sent: Tuesday, March 11, 2025 12:05 PM
To: Catania, Luke A ERDC-RDE-GRL-VA CIV <Luke.A.Catania at erdc.dren.mil>; DelazJ <delazj at gmail.com>
Cc: qgis-developer at lists.osgeo.org
Subject: Re: [QGIS-Developer] Calculate area/perimtere/length of polygon/line while editing

Hello, 

It seems there is a fix here : https://github.com/agiudiceandrea/calcarea2/blob/a6a3d7c5a98e64573731cd6a005da4e2d9836fdd/calcareaevent.py <Blockedhttps://github.com/agiudiceandrea/calcarea2/blob/a6a3d7c5a98e64573731cd6a005da4e2d9836fdd/calcareaevent.pyBlocked> 

All the best, 
S.

Le 11/03/2025 à 16:14, Catania, Luke A ERDC-RDE-GRL-VA CIV via QGIS-Developer a écrit :

Thanks. Plugin installed but will not run.  I get the error below.  I have QGIS 3.34.4.

TypeError: QgisInterface missing 'mActionDigitizeWithCurve' action 

Traceback (most recent call last):
  File "C:\PROGRA~1/QGIS33~1.4/apps/qgis-ltr/./python\qgis\utils.py", line 423, in _startPlugin
    plugins[packageName] = package.classFactory(iface)
  File "C:\Users/RDTECLAC/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\calcarea2\__init__.py", line 29, in classFactory
    return CalcAreaPlugin( iface )
  File "C:\Users/RDTECLAC/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\calcarea2\plugin.py", line 66, in __init__
    self.toolEvent = CalcAreaEvent( self.iface )
  File "C:\Users/RDTECLAC/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\calcarea2\calcareaevent.py", line 478, in __init__
    self.addFeatureEvent = AddFeatureEvent( iface )
  File "C:\Users/RDTECLAC/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\calcarea2\calcareaevent.py", line 213, in __init__
    self.geomPolygon = self.GeomPolygon( iface )
  File "C:\Users/RDTECLAC/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\calcarea2\calcareaevent.py", line 316, in __init__
    self.actionDigitizeWithCurve = getActionDigitizeWithCurve( iface )
  File "C:\Users/RDTECLAC/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\calcarea2\calcareaevent.py", line 308, in getActionDigitizeWithCurve
    raise TypeError(f"QgisInterface missing '{name}' action")
TypeError: QgisInterface missing 'mActionDigitizeWithCurve' action

From: DelazJ  <mailto:delazj at gmail.com> <delazj at gmail.com> 
Sent: Tuesday, March 11, 2025 11:08 AM
To: Catania, Luke A ERDC-RDE-GRL-VA CIV  <mailto:Luke.A.Catania at erdc.dren.mil> <Luke.A.Catania at erdc.dren.mil>
Cc: qgis-developer at lists.osgeo.org <mailto:qgis-developer at lists.osgeo.org> 
Subject: Re: [QGIS-Developer] Calculate area/perimtere/length of polygon/line while editing

Hi,

There is a CalcArea2 plugin whose description mentions it should be doing that for polygons. You might want to take ispiration from their code.

Regards,

Harrissou

Le mar. 11 mars 2025 à 15:55, Catania, Luke A ERDC-RDE-GRL-VA CIV via QGIS-Developer <qgis-developer at lists.osgeo.org <mailto:qgis-developer at lists.osgeo.org> > a écrit :

I need to calculate these values on the fly while I am in an edit session resizing a polygon or a line.  I need the user to see this calculation while they are editing not after the edits are committed. I already have the UI set up to capture after commit, but I need to capture while they are moving vertices and update the values in the UI, so they don’t keep editing and then committing just to see if they are close.  I want them to know before they commit.

Any idea how to achieve this?

Luke Catania

US Army ERDC-GRL

JCMS Site Planning Developer

_______________________________________________
QGIS-Developer mailing list
QGIS-Developer at lists.osgeo.org <mailto:QGIS-Developer at lists.osgeo.org> 
List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer <Blockedhttps://lists.osgeo.org/mailman/listinfo/qgis-developerBlocked> 
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer <Blockedhttps://lists.osgeo.org/mailman/listinfo/qgis-developerBlocked> 

_______________________________________________
QGIS-Developer mailing list
QGIS-Developer at lists.osgeo.org <mailto:QGIS-Developer at lists.osgeo.org> 
List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer <Blockedhttps://lists.osgeo.org/mailman/listinfo/qgis-developerBlocked> 
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer <Blockedhttps://lists.osgeo.org/mailman/listinfo/qgis-developerBlocked> 

-- 
Sylvain THÉRY - Ingénieur d'études CNRS en géomatique
UMR 5281 ART-Dev - Acteurs, Ressources et Territoires dans le Développement https://art-dev.cnrs.fr/ <Blockedhttps://art-dev.cnrs.fr/Blocked> 
sylvain.thery at cnrs.fr <mailto:sylvain.thery at cnrs.fr>   - +33.4.11.75.70.98
Université Paul-Valéry Montpellier 3 - Site St Charles - Bureau 239
@ postale : ART-Dev - St Charles - Route de Mende - 34 199 Montpellier Cedex 5 
https://www.researchgate.net/profile/Sylvain-Thery <Blockedhttps://www.researchgate.net/profile/Sylvain-TheryBlocked> 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20250311/5e33bb04/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 8254 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20250311/5e33bb04/attachment-0001.bin>