Hi, You can create a geometry from WKT if you have x and y fields using and expression in the field calculator. geom_from_wkt('POINT('||"x"||' '||"y"||')')
https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry Nicolas Cadieux > Le 13 nov. 2020 à 09:07, Andreas Neumann <a.neum...@carto.net> a écrit : > > > Hi > > Neither GeometryGenerators nor Vector Field Markers work on tables without > geometry, unfortunately. You didn't inform us, that you don't have geometry > in your table. > > You can, however, create a "Virtual Layer" and write some SQL to create a > geometry from your attributes: menu "Layer" --> "Create Layer" --> "New > Virtual Layer" - where you can use your existing tables and create a new > geometry column with SQL. See > https://docs.qgis.org/testing/en/docs/user_manual/managing_data_source/create_layers.html#creating-virtual-layers > > Or, if your table is a CSV file, then you can assign attribute columns to a > point geometry and then just hide the point rendering if you don't need it. > > This is an unfortunate limitation of QGIS, that there is no "easy" way to add > a geometry column to table that doesn't have geometry (or if it is possible, > then I don't know it). > > Hope this helps you, > > Andreas > >> Am 13.11.20 um 14:52 schrieb L.W.: >> Does it works on Layers with no geometry? >> >> My layers do not have a geometry. >> >> >> >> Am 13.11.2020 um 11:56 schrieb Andreas Neumann: >>> Yes, you need point data to start from, but then vectors can bei/are >>> generated from the attributes you mentioned. >>> >>> Andreas >>> >>>> Am 13.11.20 um 11:47 schrieb L.W.: >>>> from the docs ... >>>> >>>> ****It can only be used to render point data**** >>>> >>>> 12.2.2.2.6. The Vector Field Marker >>>> >>>> The vector field marker is used to display vector field data such as earth >>>> deformation, tidal flows, and the like. It displays the vectors as lines >>>> (preferably arrows) that are scaled and oriented according to selected >>>> attributes of data points. ****It can only be used to render point >>>> data****; line and polygon layers are not drawn by this symbology. >>>> >>>> The vector field is defined by attributes in the data, which can represent >>>> the field either by: >>>> >>>> cartesian components (x and y components of the field) >>>> or polar coordinates: in this case, attributes define Length and Angle. >>>> The angle may be measured either clockwise from north, or Counterclockwise >>>> from east, and may be either in degrees or radians. >>>> or as height only data, which displays a vertical arrow scaled using an >>>> attribute of the data. This is appropriate for displaying the vertical >>>> component of deformation, for example. >>>> The magnitude of field >>>> >>>> >>>> >>>> Am 13.11.2020 um 11:34 schrieb Andreas Neumann: >>>>> Or even easier: use the "Vector Field Marker": >>>>> >>>>> https://docs.qgis.org/3.10/en/docs/user_manual/style_library/symbol_selector.html?#the-vector-field-marker >>>>> >>>>> >>>>>> Am 13.11.20 um 11:33 schrieb Andreas Neumann: >>>>>> Hi, >>>>>> >>>>>> Yes - you can use Geometry Generators for that. Use the make_point() and >>>>>> make_line() expressions for that. >>>>>> >>>>>> See >>>>>> https://docs.qgis.org/3.10/en/docs/user_manual/style_library/symbol_selector.html?highlight=geometry%20generator#the-geometry-generator >>>>>> >>>>>> Greetings, >>>>>> Andreas >>>>>> >>>>>>> Am 13.11.20 um 11:26 schrieb L.W.: >>>>>>> Hi, >>>>>>> >>>>>>> is it possible to draw automatically a line between two points defined >>>>>>> by 4 fields (x1,y1 - x2,y2) in an attributetable? >>>>>>> >>>>>>> but I do not want to add a line-layer based on this table nor want to >>>>>>> draw the line by hand. >>>>>>> >>>>>>> thanks >>>>>>> >>>>>>> _______________________________________________ >>>>>>> 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 >>>>>> _______________________________________________ >>>>>> 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 >>>>> _______________________________________________ >>>>> 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 >>>> >>>> >>>> _______________________________________________ >>>> 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 >>> >>> >>> _______________________________________________ >>> 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 >> >> >> _______________________________________________ >> 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 > _______________________________________________ > 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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