Thank you Stefan,
I knew it would be as simple as that, but could not find it (the 'Java
style' in the QgsGeometry class must have made me skip experimenting
with that )
In Afrikaans (I am South African/Hungarian) there is a saying: 'As jy
dom is, moet jy ...xxx' - and that was applicable to me in this case :-)
I wrote the script yesterday in a freestanding (PyCharm) environment to
solve the issue, as I needed to 'get it done', but this info is useful
for future.
Yesterday was the first time I was trying out the function editor and,
just btw, a week or two back was when I first started writing QGis
python scripts to solve work issues.
So yes, I am struggling to find 'what is where' even though I am 10's of
years down the road picturing the algorithm needed to solve my issue.
My current challenge is also QGis Atlas with multiple sub-maps per page
- but I am 'getting there' with some pointers received from this list.
Thanks again for your response.
Kind regards,
Zoltan
On 2021-10-19 08:14, Stefan Giese (WhereGroup) wrote:
as a starting point:
/from qgis.core import *//
//from qgis.gui import *//
//
//@qgsfunction(args='auto', group='Custom', referenced_columns=[])//
//def zCutBox(feature, parent)://
// """//
// Calculates vertices and return the x coordinate of the first as
string//
// """//
// geom = feature.geometry()//
// vertices = []//
// for v in geom.vertices()://
// vertices.append(v)//
// return str(vertices[0].x())/
Am 18.10.2021 um 13:42 schrieb Zoltan:
Hi Listers,
I can't for the life of me work out the syntax/commands to use in the
FieldCalculator->FunctionEditor for extracting vertices.
I have a Polygon layer with Multipolygon rectangles at various rotations.
I need to extract the 4 corner points so that I can calculate (and
save in a virtual layer) lines that I can later use with
"Processing->Split with lines".
I will google for opening a new virtual layer and saving lines to it,
but if that is quick and easy then some help there would also be welcome.
Please can someone point me to a sample functions covering these
requirements, or just fill in the gaps below.
No, I'm not asking for someone to just write it for me.
Thanks in advance,
Zoltan
[Having a brain-dead day :-( ]
from qgis.core import *
from qgis.gui import *
@qgsfunction(args='auto', group='Custom', referenced_columns=[])
def zCutBox(feature, parent):
vertices =
blah blah
return vertices[0][0]
--
=============================================
Zoltan Szecsei GPrGISc 0031
Geograph (Pty) Ltd.
GIS and Photogrammetric Services
Cape Town, South Africa.
Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za
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Stefan Giese
Projektleiter/Consultant
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=============================================
Zoltan Szecsei GPrGISc 0031
Geograph (Pty) Ltd.
GIS and Photogrammetric Services
Cape Town, South Africa.
Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za
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