The raster calculator is a tool for raster analysis which doesn't quite suit your needs as I understand them. If you want to learn how to use the raster calculator there is a tutorial available on the QGIS changelog lessons [1].
That blog post I linked to before is likely the most effective or performant option for you, and it contains links to scripts that will perform the analysis for you. As an alternative, I have created a simple model which steps through the vectorization process of reclassifying a raster and calculating the area [2]. The data I used to test the model was the SRTM tile used in the previously mentioned lesson [1], so you can introspect it and copy the logic or tweak it as needed. I did a session on using the modeler for the last Open Day [3] so you can get familiar with them if you aren't already. [1] https://changelog.qgis.org/en/qgis/lesson/raster-16/detail/51/?q=7.2 [2] https://github.com/zacharlie/effective-dollop/blob/main/qgis-models/raster_area_calculation_example.model3 [3] https://github.com/qgis/QGIS/wiki/QOD-July-2021 On Sat, 31 Jul 2021 at 20:29, Peters <petersinmoro...@gmail.com> wrote: > Very helpful. Yes, our data is raster. I saw a calculator tool in the > raster toolbar but haven't been able to figure it out or if it's pertinent. > > On Sat, Jul 31, 2021, 19:01 Charles Dixon-Paver <char...@kartoza.com> > wrote: > >> I think you will need to provide more information on describing the input >> data, as well as how exactly you wish to process it. >> >> If your coverage data is vector areas you should be able to simply use >> the aggregate processing tool using $area as the source expression and >> stipulate a sum aggregate function. You may also use the grouping >> function to filter the results as needed using an expression. >> >> This would provide the area based on map units, so you would need to >> reproject your data into a relevant metric projection before performing the >> aggregation. A single hectare is simply 10000 m² so simple arithmetic will >> allow you to convert metric areas to hectares. >> >> If your data is another vector data type such as point clouds, you may >> need to buffer or calculate a minimum bounding geometry or convex hull >> before processing it as the area calculation will of course only work on >> area features. >> >> For raster data, the total area would be a simple calculation of the >> extents, or the dimensions and cell size. Again, you may need to reproject >> the data for it to be available in meters. >> >> If, however, you wish to segregate raster data based on cell value, you >> may want to recode and vectorize the data, or alternatively perform some >> form of custom analysis as described in the following article: >> https://www.kartoza.com/en/blog/calculating-area-of-rasters-in-qgis/ >> >> Regards >> >> On Sat, 31 Jul 2021 at 19:15, Peters <petersinmoro...@gmail.com> wrote: >> >>> Does anyone know of such a calculator as a plugin or option? At the >>> moment I am using QGIS app. Our client has asked for area coverage in sq. >>> mtrs or hectares. Appreciate any info you may have. >>> >>> -- >>> *regards,* >>> *K. Peters* >>> >>> *cell: (Morocco) +212.671.218606* >>> _______________________________________________ >>> Qgis-user mailing list >>> Qgis-user@lists.osgeo.org >>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user. >>> >>
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