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I try to style line pattern fills of polygones with the geometry-generator to get zigzag-line/wavy lines with this script Custom QGIS linestyle but somehow I never get the lines displayed. For lines & polygones it works great. Edit:

Polygone with line pattern fill, "normal" lines enter image description here

Change from simple line to geometry generator to style line in zigzag/wavy, line pattern disappears, no matter whether polygone or line is selected (outline just as illustration from a duplicated polygone)

enter image description here

What I try to get ist the zigzag/wavy style as fill pattern with the option to change "wavesize" etc. via the parameter. It is only for display/print so breaking up polygones or adding lines would be also possible, but I would prefere the elegent way @christoph did for outlines

see here

for lines

Any other solutions for wavy/zigzag-fills are welcomed. At the moment I use svg-marker-lines as workaround, but it is not very flexible. For a other workaround I thought about generating parallel lines and clip with the polygones, but again not very flexible.

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  • Please provide example screenshots of what you're aiming at, as well as what you attempted so far in detail.
    – Erik
    Aug 1, 2021 at 9:32
  • Just saw your comment gis.stackexchange.com/questions/376411/…, is the issue solved?
    – pathmapper
    Aug 1, 2021 at 11:17
  • @pathmapper: yes, for lines & polygoneoutlines it works well now, sorry for the typo.
    – user16032
    Aug 1, 2021 at 11:40
  • 1
    @user16032 good question! Never thought about creating zigzag pattern fills. Unfortunately, it seams like Geometry Generators won't work with line pattern fills at all.
    – christoph
    Aug 1, 2021 at 14:34

2 Answers 2

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4

Since QGIS 3.18 we have dynamic SVG parameters which we can use to draw wavy line pattern fills. The idea is to create dynamic SVG Bézier curves as the basis for our fills. (https://www.sitepoint.com/html5-svg-quadratic-curves/)

bezier.svg

<path d="M1,3 Q3,0  5,3 T9,3"/>

enter image description here

<svg width="1000" height="600" viewBox="0 0 10 6" xmlns="http://www.w3.org/2000/svg">
    <path d="param(path)" style="stroke:param(outline);stroke-width:param(outline-width);fill:transparent"/>
</svg>

enter image description here

We need to fiddle around with marker width,marker interval and line pattern spacing to get a reasonable result:

enter image description here

If we use a global variable (i.e. @path) instead of the expression, we can change the curve dynamically without selecting a different SVG.

enter image description here

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3

If you don't worry about using symbology styles instead of the geometry generator, you can use a marker line with a 45 degrees rotation, duplicated at 135 degrees rotation with an offset.

1

Following is the symbology exported to a QGIS style .qml file, if you want to save it and import to your layer:

<!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>
<qgis styleCategories="Symbology" version="3.18.3-Zürich">
  <renderer-v2 type="singleSymbol" symbollevels="0" forceraster="0" enableorderby="0">
    <symbols>
      <symbol type="fill" alpha="1" clip_to_extent="1" force_rhr="0" name="0">
        <data_defined_properties>
          <Option type="Map">
            <Option type="QString" value="" name="name"/>
            <Option name="properties"/>
            <Option type="QString" value="collection" name="type"/>
          </Option>
        </data_defined_properties>
        <layer enabled="1" class="LinePatternFill" pass="0" locked="0">
          <Option type="Map">
            <Option type="QString" value="45" name="angle"/>
            <Option type="QString" value="0,0,0,255" name="color"/>
            <Option type="QString" value="5" name="distance"/>
            <Option type="QString" value="3x:0,0,0,0,0,0" name="distance_map_unit_scale"/>
            <Option type="QString" value="MM" name="distance_unit"/>
            <Option type="QString" value="0.5" name="line_width"/>
            <Option type="QString" value="3x:0,0,0,0,0,0" name="line_width_map_unit_scale"/>
            <Option type="QString" value="MM" name="line_width_unit"/>
            <Option type="QString" value="0" name="offset"/>
            <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_map_unit_scale"/>
            <Option type="QString" value="MM" name="offset_unit"/>
            <Option type="QString" value="3x:0,0,0,0,0,0" name="outline_width_map_unit_scale"/>
            <Option type="QString" value="MM" name="outline_width_unit"/>
          </Option>
          <prop k="angle" v="45"/>
          <prop k="color" v="0,0,0,255"/>
          <prop k="distance" v="5"/>
          <prop k="distance_map_unit_scale" v="3x:0,0,0,0,0,0"/>
          <prop k="distance_unit" v="MM"/>
          <prop k="line_width" v="0.5"/>
          <prop k="line_width_map_unit_scale" v="3x:0,0,0,0,0,0"/>
          <prop k="line_width_unit" v="MM"/>
          <prop k="offset" v="0"/>
          <prop k="offset_map_unit_scale" v="3x:0,0,0,0,0,0"/>
          <prop k="offset_unit" v="MM"/>
          <prop k="outline_width_map_unit_scale" v="3x:0,0,0,0,0,0"/>
          <prop k="outline_width_unit" v="MM"/>
          <data_defined_properties>
            <Option type="Map">
              <Option type="QString" value="" name="name"/>
              <Option name="properties"/>
              <Option type="QString" value="collection" name="type"/>
            </Option>
          </data_defined_properties>
          <symbol type="line" alpha="1" clip_to_extent="1" force_rhr="0" name="@0@0">
            <data_defined_properties>
              <Option type="Map">
                <Option type="QString" value="" name="name"/>
                <Option name="properties"/>
                <Option type="QString" value="collection" name="type"/>
              </Option>
            </data_defined_properties>
            <layer enabled="1" class="MarkerLine" pass="0" locked="0">
              <Option type="Map">
                <Option type="QString" value="4" name="average_angle_length"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="average_angle_map_unit_scale"/>
                <Option type="QString" value="MM" name="average_angle_unit"/>
                <Option type="QString" value="5" name="interval"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="interval_map_unit_scale"/>
                <Option type="QString" value="MM" name="interval_unit"/>
                <Option type="QString" value="5.55112e-17" name="offset"/>
                <Option type="QString" value="2.5" name="offset_along_line"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_along_line_map_unit_scale"/>
                <Option type="QString" value="MM" name="offset_along_line_unit"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_map_unit_scale"/>
                <Option type="QString" value="MM" name="offset_unit"/>
                <Option type="QString" value="interval" name="placement"/>
                <Option type="QString" value="0" name="ring_filter"/>
                <Option type="QString" value="1" name="rotate"/>
              </Option>
              <prop k="average_angle_length" v="4"/>
              <prop k="average_angle_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="average_angle_unit" v="MM"/>
              <prop k="interval" v="5"/>
              <prop k="interval_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="interval_unit" v="MM"/>
              <prop k="offset" v="5.55112e-17"/>
              <prop k="offset_along_line" v="2.5"/>
              <prop k="offset_along_line_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="offset_along_line_unit" v="MM"/>
              <prop k="offset_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="offset_unit" v="MM"/>
              <prop k="placement" v="interval"/>
              <prop k="ring_filter" v="0"/>
              <prop k="rotate" v="1"/>
              <data_defined_properties>
                <Option type="Map">
                  <Option type="QString" value="" name="name"/>
                  <Option name="properties"/>
                  <Option type="QString" value="collection" name="type"/>
                </Option>
              </data_defined_properties>
              <symbol type="marker" alpha="1" clip_to_extent="1" force_rhr="0" name="@@0@0@0">
                <data_defined_properties>
                  <Option type="Map">
                    <Option type="QString" value="" name="name"/>
                    <Option name="properties"/>
                    <Option type="QString" value="collection" name="type"/>
                  </Option>
                </data_defined_properties>
                <layer enabled="1" class="SimpleMarker" pass="0" locked="0">
                  <Option type="Map">
                    <Option type="QString" value="135" name="angle"/>
                    <Option type="QString" value="255,0,0,255" name="color"/>
                    <Option type="QString" value="1" name="horizontal_anchor_point"/>
                    <Option type="QString" value="miter" name="joinstyle"/>
                    <Option type="QString" value="line" name="name"/>
                    <Option type="QString" value="0,0" name="offset"/>
                    <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_map_unit_scale"/>
                    <Option type="QString" value="MM" name="offset_unit"/>
                    <Option type="QString" value="0,0,0,255" name="outline_color"/>
                    <Option type="QString" value="solid" name="outline_style"/>
                    <Option type="QString" value="0.4" name="outline_width"/>
                    <Option type="QString" value="3x:0,0,0,0,0,0" name="outline_width_map_unit_scale"/>
                    <Option type="QString" value="MM" name="outline_width_unit"/>
                    <Option type="QString" value="diameter" name="scale_method"/>
                    <Option type="QString" value="3" name="size"/>
                    <Option type="QString" value="3x:0,0,0,0,0,0" name="size_map_unit_scale"/>
                    <Option type="QString" value="MM" name="size_unit"/>
                    <Option type="QString" value="1" name="vertical_anchor_point"/>
                  </Option>
                  <prop k="angle" v="135"/>
                  <prop k="color" v="255,0,0,255"/>
                  <prop k="horizontal_anchor_point" v="1"/>
                  <prop k="joinstyle" v="miter"/>
                  <prop k="name" v="line"/>
                  <prop k="offset" v="0,0"/>
                  <prop k="offset_map_unit_scale" v="3x:0,0,0,0,0,0"/>
                  <prop k="offset_unit" v="MM"/>
                  <prop k="outline_color" v="0,0,0,255"/>
                  <prop k="outline_style" v="solid"/>
                  <prop k="outline_width" v="0.4"/>
                  <prop k="outline_width_map_unit_scale" v="3x:0,0,0,0,0,0"/>
                  <prop k="outline_width_unit" v="MM"/>
                  <prop k="scale_method" v="diameter"/>
                  <prop k="size" v="3"/>
                  <prop k="size_map_unit_scale" v="3x:0,0,0,0,0,0"/>
                  <prop k="size_unit" v="MM"/>
                  <prop k="vertical_anchor_point" v="1"/>
                  <data_defined_properties>
                    <Option type="Map">
                      <Option type="QString" value="" name="name"/>
                      <Option name="properties"/>
                      <Option type="QString" value="collection" name="type"/>
                    </Option>
                  </data_defined_properties>
                </layer>
              </symbol>
            </layer>
            <layer enabled="1" class="MarkerLine" pass="0" locked="0">
              <Option type="Map">
                <Option type="QString" value="4" name="average_angle_length"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="average_angle_map_unit_scale"/>
                <Option type="QString" value="MM" name="average_angle_unit"/>
                <Option type="QString" value="5" name="interval"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="interval_map_unit_scale"/>
                <Option type="QString" value="MM" name="interval_unit"/>
                <Option type="QString" value="0" name="offset"/>
                <Option type="QString" value="0" name="offset_along_line"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_along_line_map_unit_scale"/>
                <Option type="QString" value="MM" name="offset_along_line_unit"/>
                <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_map_unit_scale"/>
                <Option type="QString" value="MM" name="offset_unit"/>
                <Option type="QString" value="interval" name="placement"/>
                <Option type="QString" value="0" name="ring_filter"/>
                <Option type="QString" value="1" name="rotate"/>
              </Option>
              <prop k="average_angle_length" v="4"/>
              <prop k="average_angle_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="average_angle_unit" v="MM"/>
              <prop k="interval" v="5"/>
              <prop k="interval_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="interval_unit" v="MM"/>
              <prop k="offset" v="0"/>
              <prop k="offset_along_line" v="0"/>
              <prop k="offset_along_line_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="offset_along_line_unit" v="MM"/>
              <prop k="offset_map_unit_scale" v="3x:0,0,0,0,0,0"/>
              <prop k="offset_unit" v="MM"/>
              <prop k="placement" v="interval"/>
              <prop k="ring_filter" v="0"/>
              <prop k="rotate" v="1"/>
              <data_defined_properties>
                <Option type="Map">
                  <Option type="QString" value="" name="name"/>
                  <Option name="properties"/>
                  <Option type="QString" value="collection" name="type"/>
                </Option>
              </data_defined_properties>
              <symbol type="marker" alpha="1" clip_to_extent="1" force_rhr="0" name="@@0@0@1">
                <data_defined_properties>
                  <Option type="Map">
                    <Option type="QString" value="" name="name"/>
                    <Option name="properties"/>
                    <Option type="QString" value="collection" name="type"/>
                  </Option>
                </data_defined_properties>
                <layer enabled="1" class="SimpleMarker" pass="0" locked="0">
                  <Option type="Map">
                    <Option type="QString" value="45" name="angle"/>
                    <Option type="QString" value="255,0,0,255" name="color"/>
                    <Option type="QString" value="1" name="horizontal_anchor_point"/>
                    <Option type="QString" value="miter" name="joinstyle"/>
                    <Option type="QString" value="line" name="name"/>
                    <Option type="QString" value="0,0" name="offset"/>
                    <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_map_unit_scale"/>
                    <Option type="QString" value="MM" name="offset_unit"/>
                    <Option type="QString" value="0,0,0,255" name="outline_color"/>
                    <Option type="QString" value="solid" name="outline_style"/>
                    <Option type="QString" value="0.4" name="outline_width"/>
                    <Option type="QString" value="3x:0,0,0,0,0,0" name="outline_width_map_unit_scale"/>
                    <Option type="QString" value="MM" name="outline_width_unit"/>
                    <Option type="QString" value="diameter" name="scale_method"/>
                    <Option type="QString" value="3" name="size"/>
                    <Option type="QString" value="3x:0,0,0,0,0,0" name="size_map_unit_scale"/>
                    <Option type="QString" value="MM" name="size_unit"/>
                    <Option type="QString" value="1" name="vertical_anchor_point"/>
                  </Option>
                  <prop k="angle" v="45"/>
                  <prop k="color" v="255,0,0,255"/>
                  <prop k="horizontal_anchor_point" v="1"/>
                  <prop k="joinstyle" v="miter"/>
                  <prop k="name" v="line"/>
                  <prop k="offset" v="0,0"/>
                  <prop k="offset_map_unit_scale" v="3x:0,0,0,0,0,0"/>
                  <prop k="offset_unit" v="MM"/>
                  <prop k="outline_color" v="0,0,0,255"/>
                  <prop k="outline_style" v="solid"/>
                  <prop k="outline_width" v="0.4"/>
                  <prop k="outline_width_map_unit_scale" v="3x:0,0,0,0,0,0"/>
                  <prop k="outline_width_unit" v="MM"/>
                  <prop k="scale_method" v="diameter"/>
                  <prop k="size" v="3"/>
                  <prop k="size_map_unit_scale" v="3x:0,0,0,0,0,0"/>
                  <prop k="size_unit" v="MM"/>
                  <prop k="vertical_anchor_point" v="1"/>
                  <data_defined_properties>
                    <Option type="Map">
                      <Option type="QString" value="" name="name"/>
                      <Option name="properties"/>
                      <Option type="QString" value="collection" name="type"/>
                    </Option>
                  </data_defined_properties>
                </layer>
              </symbol>
            </layer>
          </symbol>
        </layer>
        <layer enabled="1" class="SimpleFill" pass="0" locked="0">
          <Option type="Map">
            <Option type="QString" value="3x:0,0,0,0,0,0" name="border_width_map_unit_scale"/>
            <Option type="QString" value="0,0,255,255" name="color"/>
            <Option type="QString" value="bevel" name="joinstyle"/>
            <Option type="QString" value="0,0" name="offset"/>
            <Option type="QString" value="3x:0,0,0,0,0,0" name="offset_map_unit_scale"/>
            <Option type="QString" value="MM" name="offset_unit"/>
            <Option type="QString" value="35,35,35,255" name="outline_color"/>
            <Option type="QString" value="solid" name="outline_style"/>
            <Option type="QString" value="0.26" name="outline_width"/>
            <Option type="QString" value="MM" name="outline_width_unit"/>
            <Option type="QString" value="no" name="style"/>
          </Option>
          <prop k="border_width_map_unit_scale" v="3x:0,0,0,0,0,0"/>
          <prop k="color" v="0,0,255,255"/>
          <prop k="joinstyle" v="bevel"/>
          <prop k="offset" v="0,0"/>
          <prop k="offset_map_unit_scale" v="3x:0,0,0,0,0,0"/>
          <prop k="offset_unit" v="MM"/>
          <prop k="outline_color" v="35,35,35,255"/>
          <prop k="outline_style" v="solid"/>
          <prop k="outline_width" v="0.26"/>
          <prop k="outline_width_unit" v="MM"/>
          <prop k="style" v="no"/>
          <data_defined_properties>
            <Option type="Map">
              <Option type="QString" value="" name="name"/>
              <Option name="properties"/>
              <Option type="QString" value="collection" name="type"/>
            </Option>
          </data_defined_properties>
        </layer>
      </symbol>
    </symbols>
    <rotation/>
    <sizescale/>
  </renderer-v2>
  <blendMode>0</blendMode>
  <featureBlendMode>0</featureBlendMode>
  <layerGeometryType>2</layerGeometryType>
</qgis>
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2
  • 1
    thanks for your help! Your solution is similar to what I meant with point pattern svg fill, but much more elegant! Still missing the options with @christoph solutions for lines. A very undervalued post imho.
    – user16032
    Aug 4, 2021 at 10:43
  • 1
    thanks @user16032 for giving me credit. Looks like there‘s not so much need for custom line styles in QGIS ;-) Did it for our geologists… and they are happy now.
    – christoph
    Aug 5, 2021 at 16:29

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