I would suggest using an embedded SVG marker, for which you can set data defined properties for width and height.
I don't think there is a straight line/ block marker, but you can probably find one somewhere using the resource sharing plugin. Alternatively, you can make a custom SVG in inkscape and get it "qgis ready" using the script at https://github.com/zacharlie/fonts4gis/blob/master/parameterise.py I have one that's semi-suitable online ready, but with rounded edges, at https://github.com/zacharlie/svg4qgis/blob/master/svg/TN.svg Perhaps test with that and see if you have any luck. Otherwise, I can help make one for you if you have trouble with inkscape or the processing script, but more information of what you want it to look like would help. As for your expression, from what I can gather you are looking for a nested if statement or case expression: ``` CASE WHEN ("crossfall"<0) THEN "heading"-90 WHEN ("crossfall">0) THEN "heading"+90 ELSE 0 END ``` Or: ``` if("crossfall"<0,"heading"-90, if("crossfall">0,"heading"+90,0 )) ``` This is assuming your fields are using the correct datatypes, although there are expressions for changing them. Hope that helps On Mon, 2 Nov 2020 at 18:27, Roland Spielhofer <[email protected]> wrote: > Hi, > I have a trajectory of a vehicle (= a list of points including heading, > crossfall, slope, curvature, radius, ...) and would like to visualise the > crossfall. Per point there should be a line pointing left or right > (transverse to driving direction) with the line having a length according > to the quantity of the crossfall and pointing to left if negative, to right > if positive. > > I have tried font marker - an arrow to visualize heading which works well. > But with the crossfall I struggle. > > The font marker may be not the right joice, as it makes the lines not only > longer, but also thicker. > What type of marker would right for this? Should just be a simple line > that alters in length according to crossfall > > How would the expression look like to handle the case crossfall<0 -> > heading-90; crossfall>0 -> heading+90 > > Any help appreciated! > TIA > Roland > > _______________________________________________ > 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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