| A Graphic is a "graphical symbol" with an inherent shape, color(s), and
possibly size.
A "graphic" can very informally be defined as "a little picture" and can be
of either a raster or vector graphic source type. The term graphic is used
since the term "symbol" is similar to "symbolizer" which is used in a
difference context in SLD. The graphical symbol to display can be provided
either as an external graphical resource or as a Mark.
Multiple external URLs and marks can be referenced with the proviso that
they all provide equivalent graphics in different formats. The 'hot spot'
to use for positioning the rendering at a point must either be inherent
from the external format or be defined to be the "central point" of the
graphic.
The details of this object are taken from the OGC
Styled-Layer Descriptor Report (OGC 02-070) version 1.0.0.:
<xsd:element name="Graphic">
<xsd:annotation>
<xsd:documentation>
A "Graphic" specifies or refers to a "graphic symbol" with inherent
shape, size, and coloring.
</xsd:documentation>
</xsd:annotation>
<xsd:complexType>
<xsd:sequence>
<xsd:choice minOccurs="0" maxOccurs="unbounded">
<xsd:element ref="sld:ExternalGraphic"/>
<xsd:element ref="sld:Mark"/>
</xsd:choice>
<xsd:sequence>
<xsd:element ref="sld:Opacity" minOccurs="0"/>
<xsd:element ref="sld:Size" minOccurs="0"/>
<xsd:element ref="sld:Rotation" minOccurs="0"/>
</xsd:sequence>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
Renderers can ue this information when displaying styled features, though it
must be remembered that not all renderers will be able to fully represent
strokes as set out by this interface. For example, opacity may not be
supported.
Notes:
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The graphical parameters and their values are derived from SVG/CSS2
standards with names and semantics which are as close as possible.
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