Hi, The WKT for a linestring should look like this.
LINESTRING (30 10, 10 30, 40 40) I think you should use geom_from_wkt, no « to » but if I follow your logic, it should probably be make_linestring or something like that. > > geom_to_wkt > ( > make_line... > If you send me a few lines of your file, I will test it out for you. https://docs.qgis.org/3.16/en/docs/user_manual/working_with_vector/functions_list.html?highlight=geom_from_wkt#geom-from-wkt Nicolas Cadieux > Le 14 nov. 2020 à 07:53, L.W. <[email protected]> a écrit : > > > I tried a lot ... > > I have a point-layer, I put this code in symbol -> single symbol -> > geometrygenerator > > What is wrong? Hi > > > > geom_to_wkt > ( > make_line > ( > make_point > ( > 5826542.703128459, > 797907.3304607988 > ), > make_point > ( > 5827473.536854242, > 796987.0074038045 > ), > make_point > ( > 5827167.893279332, > 795128.2317764781 > ), > make_point > ( > 5826835.7783904355, > 793227.8583700341 > ) > ) > ) > > > Am 13.11.2020 um 15:24 schrieb Andreas Neumann: >> Hi Nicolas, >> >> Yes - but that doesn't magically turn a "non geometry" table into a >> "geometry table" - as far as I know. So you probably need to create a >> "Virtual Layer" and create the geometry similar to what you propose. >> >> Andreas >> >> Am 13.11.20 um 15:22 schrieb Nicolas Cadieux: >>> 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 <[email protected]> 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 >>>>>>>>>> [email protected] >>>>>>>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>>>> _______________________________________________ >>>>>>>>> Qgis-user mailing list >>>>>>>>> [email protected] >>>>>>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>>> _______________________________________________ >>>>>>>> Qgis-user mailing list >>>>>>>> [email protected] >>>>>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> Qgis-user mailing list >>>>>>> [email protected] >>>>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Qgis-user mailing list >>>>>> [email protected] >>>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>> >>>>> >>>>> _______________________________________________ >>>>> Qgis-user mailing list >>>>> [email protected] >>>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>> _______________________________________________ >>>> Qgis-user mailing list >>>> [email protected] >>>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >> >> >> _______________________________________________ >> Qgis-user mailing list >> [email protected] >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > _______________________________________________ > Qgis-user mailing list > [email protected] > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
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