Proportional symbol

[ebocher]

Existing conformance classes required for this use case:

• vector feature styling
• viz/feature.pass (define conformance classes) :firecracker:
• geometry selection :firecracker:
• Geometry Manipulation Functions (centroid :firecracker:)
• Interpolate function :firecracker:
• Shape Graphics

Example stylesheet:

Below a CSS encoding to describe a proportionnal symbol map to display number of inhabitants on a regular grid (SUM_POP property).

*{
  stroke: grey;
  stroke-width: 1px;
  [SUM_POP>0] {
    geometry: centroid(the_geom);
    mark:   symbol(circle);
    mark-size: [Interpolate(
         SUM_POP,
         0, 10,
         30, 20,
         84, 100,
         'numeric',
         'linear')];
   :mark {
       fill: orange;
       fill-opacity: 0.2;
       stroke: black;
       stroke-width : 1px;
     }
  }
}

Describe any capability not already addressed by existing conformance classes:

Example image illustrating the portrayal use case:

[jerstlouis]

[viz.pass = 1]
{
   stroke: { color: grey, width: 1 };
}
[viz.pass = 2][SUM_POP>0]
{
   geometry: centroid(the_geom);
   marker: Circle {
       fill: { color: orange, opacity: 0.2 };
       stroke: { color: black, width : 1 };
       radius: interpolate(SUM_POP, { 0: 10,  30: 20, 84: 100 }, numeric, linear);
   }
}

[oertz]

[feature.pass = 1]
{
   stroke: { color: grey, width: 1 };
}
[feature.pass = 2][SUM_POP>0]
{
   geometry: centroid(the_geom);
   marker: Circle {
       fill: { color: orange, opacity: 0.2 };
       stroke: { color: black, width : 1 };
       radius: interpolate(SUM_POP, { 0: 10,  30: 20, 84: 100 }, numeric, linear);
   }
}

[oertz]

*{
  stroke: grey;
  stroke-width: 1px;
}

[SUM_POP>0] {
    geometry: centroid(the_geom);
    mark:   symbol(circle);
    mark-size: [Interpolate(
         SUM_POP,
         0, 10,
         30, 20,
         84, 100,
         'numeric',
         'linear')];
   :mark {
       fill: orange;
       fill-opacity: 0.2;
       stroke: black;
       stroke-width : 1px;
     }
}

[maxcollombin]

Mapbox JSON encoding

NOTE:: MarkSymbolizer.wellKnownName is only partially supported by used parser: Only circle symbolizers are supported for the moment.

{
  "version": 8,
  "name": "Default Styler",
  "layers": [
    {
      "filter": [
        ">",
        "SUM_POP",
        0
      ],
      "id": "",
      "type": "line",
      "paint": {
        "line-color": "#808080"
      }
    },
    {
      "filter": [
        ">",
        "SUM_POP",
        0
      ],
      "id": "",
      "type": "circle",
      "paint": {
        "circle-radius": null,
        "circle-color": "#ffa500",
        "circle-opacity": 0.2
      }
    },
    {
      "filter": [
        "<=",
        "SUM_POP",
        0
      ],
      "id": "",
      "type": "line",
      "paint": {
        "line-color": "#808080"
      }
    }
  ]
}

[maxcollombin]

SLD encoding

<?xml version="1.0" encoding="UTF-8"?>
<sld:StyledLayerDescriptor
    xmlns="http://www.opengis.net/sld"
    xmlns:sld="http://www.opengis.net/sld"
    xmlns:gml="http://www.opengis.net/gml"
    xmlns:ogc="http://www.opengis.net/ogc" version="1.0.0">
    <sld:NamedLayer>
        <sld:Name>Default Styler</sld:Name>
        <sld:UserStyle>
            <sld:Name>Default Styler</sld:Name>
            <sld:FeatureTypeStyle>
                <sld:Name>name</sld:Name>
                <sld:Rule>
                    <ogc:Filter>
                        <ogc:PropertyIsGreaterThan>
                            <ogc:PropertyName>SUM_POP</ogc:PropertyName>
                            <ogc:Literal>0</ogc:Literal>
                        </ogc:PropertyIsGreaterThan>
                    </ogc:Filter>
                    <sld:LineSymbolizer>
                        <sld:Stroke>
                            <sld:CssParameter name="stroke">#808080</sld:CssParameter>
                        </sld:Stroke>
                    </sld:LineSymbolizer>
                    <sld:PointSymbolizer>
                        <sld:Graphic>
                            <sld:Mark>
                                <sld:WellKnownName>circle</sld:WellKnownName>
                                <sld:Fill>
                                    <sld:CssParameter name="fill">#ffa500</sld:CssParameter>
                                    <sld:CssParameter name="fill-opacity">0.2</sld:CssParameter>
                                </sld:Fill>
                                <sld:Stroke/>
                            </sld:Mark>
                            <sld:Size>
                                <ogc:Function name="Interpolate">
                                    <ogc:PropertyName>SUM_POP</ogc:PropertyName>
                                    <ogc:Literal>0</ogc:Literal>
                                    <ogc:Literal>10</ogc:Literal>
                                    <ogc:Literal>30</ogc:Literal>
                                    <ogc:Literal>20</ogc:Literal>
                                    <ogc:Literal>84</ogc:Literal>
                                    <ogc:Literal>100</ogc:Literal>
                                    <ogc:Literal>numeric</ogc:Literal>
                                    <ogc:Literal>linear</ogc:Literal>
                                </ogc:Function>
                            </sld:Size>
                        </sld:Graphic>
                    </sld:PointSymbolizer>
                </sld:Rule>
                <sld:Rule>
                    <ogc:Filter>
                        <ogc:PropertyIsLessThanOrEqualTo>
                            <ogc:PropertyName>SUM_POP</ogc:PropertyName>
                            <ogc:Literal>0</ogc:Literal>
                        </ogc:PropertyIsLessThanOrEqualTo>
                    </ogc:Filter>
                    <sld:LineSymbolizer>
                        <sld:Stroke>
                            <sld:CssParameter name="stroke">#808080</sld:CssParameter>
                        </sld:Stroke>
                    </sld:LineSymbolizer>
                </sld:Rule>
                <sld:VendorOption name="ruleEvaluation">first</sld:VendorOption>
            </sld:FeatureTypeStyle>
        </sld:UserStyle>
    </sld:NamedLayer>
</sld:StyledLayerDescriptor>