Sized Arrows
Whilst the most common way of representing vectors is to use a raster layer for the magnitude and an arrow layer for the direction, we also provide a way to control the size of the arrows using the value of another field (usually the magnitude). The <resc:SizedArrowSymbolizer> element is used to achieve this. As per the <resc:ArrowSymbolizer>, the data field should be a set of directions given as an angular compass bearing (degrees clockwise from North). The following tags can be used within this element:
| Tag name | Type of contents | Default value | Description |
|---|---|---|---|
<resc:ArrowSizeField> |
String | Must be specified | The data layer named used to scale the arrows |
<resc:ArrowMinSize> |
Integer | 4 | The minimum size (in pixels) of the arrows |
<resc:ArrowMaxSize> |
Integer | 12 | The maximum size (in pixels) of the arrows |
<resc:ArrowColour> |
String | #FF000000 (Black) | Colour of arrows |
<resc:ArrowBackground> |
String | transparent | Colour of the background |
<resc:ArrowStyle> |
String | THIN_ARROW | Style of the arrows to plot. Accepts the values "THIN_ARROW" (a normal arrow), "FAT_ARROW" (a wider version), "TRI_ARROW" (a long isosceles triangle), "UPSTREAM" (dots with a line pointing in the desired direction) |
<resc:ArrowDirectionConvention> |
String | DEFAULT | Convention for the arrows direction. Accepts the values "DEFAULT", "METEOROLOGICAL" (not supported for styles "UPSTREAM", "WIND_BARBS") |
<resc:Range> |
XML element | Must be specified | Specifies the range of the data used to scale the arrows |
For example:
<resc:SizedArrowSymbolizer>
<resc:ArrowSizeField>wind_speed_magnitude</resc:ArrowSizeField>
<resc:ArrowMinSize>4</resc:ArrowMinSize>
<resc:ArrowMaxSize>12</resc:ArrowMaxSize>
<resc:ArrowColour>#FF000000</resc:ArrowColour>
<resc:ArrowStyle>FAT_ARROW</resc:ArrowStyle>
<resc:ArrowDirectionConvention>DEFAULT</resc:ArrowDirectionConvention>
<resc:Range>
<resc:Minimum>0</resc:Minimum>
<resc:Maximum>5</resc:Maximum>
<resc:Spacing>linear</resc:Spacing>
</resc:Range>
</resc:SizedArrowSymbolizer>