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Geometry

Posted: Wed Jan 29, 2020 3:43 pm
by claudiacp
Geometry
Dear ENVI-met team
I have a question about the importing vector shape for Monde. When exporting the QGIS shapefile to Monde, the geometry was not recognized. In the first import to MONDE the geometry was recognized, but when I exported to the Modelling area it was not recognized. What I noticed is that all polygons on islands have not been recognized. However, in QGIS/Monde GIS is being recognized. I did some tests and segmented the polygons so as not to show the islands, it worked. Do I need to perform this procedure on all polygons? Or have a simple solution for large urban areas? Attached is the file containing the information.
Best regards,
Cláudia

Re: Geometry

Posted: Wed Jan 29, 2020 4:26 pm
by Tim
Hi Cláudia,

There are difficulties with polygons that have erased parts in them. They may origin from a erase process? Otherwise, the ID of the polygon might not be found in the database and is thus not recognized.

Best regards,
Tim

Re: Geometry

Posted: Wed Jan 29, 2020 7:31 pm
by claudiacp
Dear Tim
They do not originate from an erasure process. All polygons also have an ID. I am sending file attachments for you to evaluate. Thanks a lot.
Best regards,
Cláudia

Re: Geometry

Posted: Thu Jan 30, 2020 8:42 am
by Tim
Hi Cláudia,

You attached the monde file and the respective shapefiles. One without island and one with island. The one you called without island is how Monde is able to recognize structures. It went well, all streets are recognized correctly. The one with island includes a part in the middle that is wrongly recognized as street (the part that you call island). This island is safed as counterclockwise digitize part in the shapefile. If you generated it by erasing or any tool is not important. The results is that you get a polygon within another polygon which shall not be used for the export. Monde cannot handle that, yet. You thus need to digitize the polygons without islands as you call it.

Best regards,
Tim

Re: Geometry

Posted: Thu Jan 30, 2020 6:02 pm
by claudiacp
Dear Tim,
Thank you very much for responding to my request.

Best regards,
Cláudia

Re: Geometry

Posted: Sat Feb 01, 2020 10:14 am
by enviadmin
Basically if a polygon is within another polygon this is a non- standard situation.
Some people use this to generate holes in closed polys by defining the points anti-clockwise. Monde recognoizes this method and defines those as erase polygons.
All other situations are undefined and the larger polgon must me removed if it is on the same layer as eg the buildings. If it is on a different layer, this layer can be und turned off when exporting
Michael