Re: [Qgis-user] creating vector layer from slope map with few classes

2022-03-29 Thread Shinoto, PD Dr. Maria via Qgis-user
Nicolas, Tried it once again, short names and reasonable paths do not work. I am on Mac, QGIS 3.24, will test some reasons for the failure tomorrow again and report. Thanks for your advice, Maria > Am 30.03.2022 um 09:34 schrieb Nicolas Cadieux via Qgis-user > : > > Hi, > > "Polygonize"

Re: [Qgis-user] creating vector layer from slope map with few classes

2022-03-29 Thread Nicolas Cadieux via Qgis-user
Hi, "Polygonize" should work well to vectorize the raster classes. If you have problems with the file name, try simplifying the file name to the bare minimun like c:\temp\toto.shp if you're on Windows. Make sure you have no spaces or accents in the path (this includes the user path of your op

Re: [Qgis-user] creating vector layer from slope map with few classes

2022-03-29 Thread Shinoto, PD Dr. Maria via Qgis-user
Hi Kirk, that was helpful, thank you. I am not yet where I need to be, but so far I could create two classes with the formula found in the docs (https://docs.qgis.org/3.10/en/docs/user_manual/working_with_raster/raster_analysis.html) along this line: `("slope@1" < 50) * 1 + ("slope

Re: [Qgis-user] creating vector layer from slope map with few classes

2022-03-29 Thread kirk via Qgis-user
Hi Maria.The symbology does not reclassify the underlying raster, it just changes the way it is displayed.  Use the raster calculator to generate a new raster with the Classes you require. The native qgis calculator works well. You can find it in the upper word menu under raster.  Once  you have

[Qgis-user] creating vector layer from slope map with few classes

2022-03-29 Thread Shinoto, PD Dr. Maria via Qgis-user
Hi, I have created a slope map from a DTM. I have limited the symbology to three meaningful classes and wish to create a vector layer with polygons of three classes from that. The conditions are One-Channel-Pseudocolor, Channel1 (Gray), interpolation discrete, modus "fortlaufend" -- not iden