[Qgis-user] Dynamic Line

[L.W.]

from the docs ...

****It can only be used to render point data****


        12.2.2.2.6.The Vector Field Marker
        <https://docs.qgis.org/3.10/en/docs/user_manual/style_library/symbol_selector.html?#id15>

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
>>>
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