[Qgis-user] Point order in WKT export from polygon layer

[Reetz, Michael (NLPVW)]

I've tested both options, the plugin and the function.

The plugin is for single taxa and whole countries (Germany in my case). This would be a good tool to visualize occurrences for, e. g., a species someone is interested in. Unfortunately, the internet connection to gbif.org fails. Maybe the plugin doesn't use the systems proxy settings.

The function works perfectly. Combined with "transform" it gives me a WKT representation of my areas in the correct CRS for GBIF.

Thanks again.

Best regard,
Michael

-----Ursprüngliche Nachricht-----
Von: Reetz, Michael (NLPVW) 
Gesendet: Dienstag, 6. August 2024 09:57
An: qgis-user at lists.osgeo.org
Betreff: AW: [Qgis-user] Point order in WKT export from polygon layer

Dear Ian, Andrea, and Richard,

thanks for your quick response. I will try out the options. GBIF defines a "clockwise" polygon as "all outside the polygon" and a "counter clockwise" polygon as "all inside the polygon". I didn't find this as rule in an OGC standard but it was mentioned as OGC standard in other sources (I didn't save the links).

Best regards,
MIchael

-----Ursprüngliche Nachricht-----
Von: Richard Duivenvoorde <rdmailings at duif.net> 
Gesendet: Dienstag, 6. August 2024 06:36
An: Reetz, Michael (NLPVW) <Michael.Reetz at nlpvw.niedersachsen.de>; qgis-user at lists.osgeo.org
Betreff: Re: [Qgis-user] Point order in WKT export from polygon layer

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On 8/5/24 14:33, Reetz, Michael (NLPVW) via QGIS-User wrote:
> Dear list,
> 
> I’ve created a csv-file with coordinates in WKT-format by exporting a polygon layer with the “Save object as …”-option (“Objekte speichern als …” in the German QGIS version). I need this for querying data from GBIF via their API using JSON input. That has worked for the last years. But using the same JSON files this year gives an error because the point order is clockwise. I’ve found that according to the OGC standard the order should be counter clockwise for polygons and clockwise for excluded areas inside a polygon. It seems as if GBIF is following this standard now.
> 
> Would it be possible to follow the OGC standard in the QGIS export, too? This would reduce the amount of rework after each export.

First thing I thought: this would be a nice simple plugin :-)

"Just download features from GBIF api"..

Did not check, but found:

https://plugins.qgis.org/plugins/qgisgbifapi/

Have not tried/tested, but maybe that is an option too?

Regards,

Richard Duivenvoorde