Package org.geotools.styling

Allows for symbolization of geospatial data.

For many of us in geotools *this* is the reason we came along for the ride - a pretty picture. The contents of this package are adapted from the OpenGIS® Styled Layer Descriptor specification v1.0.0.

Conformance to SLD 1.0.0

We may experiment with our own (or SLD 1.1) ideas but will mark such experiments for you. This is only an issue of you are considering writing out these objects for interoptability with other systems.

General stratagy for supporting multiple SLD versions (and experiments):

• These interfaces will reflect the current published specification
• Our implementations will be BIGGER and more capabile then any one specification
• We cannot defined explicit interfaces tracking each version until we move to Java 5 (perferably GeoAPI would hold these anyways)
• We can provided javadocs indicating extentions, and isolate these using the normal java convention: TextSymbolizer and TextSymbolizer2 (In short you will have to go out of your way to work with a hack or experiment, you won't depend on one by accident)
• We can use Factories (aka SLD1Factory and SLD1_1Factory and SEFactory) to support the creation of conformant datastructures. Code (such as user interfaces) can be parameratized with these factories when they need to confirm to an exact version supported by an individual service. We hope that specifications are always adative, and will be forced to throw unsupported exceptions when functionality is removed from a specification.

Care and Feeding of Style Objects

SLD is an XML specification, the definition of objects capturing this information, the binding of objects to these XML documents, and the provision of events on object modification all need to be accounted for.

StyleFactory

As with all geotools work construction of styling constructs is handled by a Factory(GOF). Quickly a Factory is used when working with interfaces, anything that would of been a constructor is set up as an create method.

  StyleFactory factory = StyleFactoryFinder.createStyleFactory();
  StyleLayerDescriptor sld = factory.createStyleLayerDescriptor();
  // an empty sld document
  sld.setTitle("Basic Black");
  sld.setAbstract("Grayscale style suitable for use with photocopiers");
  
  

When creating a complex data structure direct use of a Factory is a pain. Which leads us to the next section.

Notes:

• At this time one implementation of StyleFactory is available, this will not provide true in the future (as SLD experiments, and code generation are brought to bare on future specifications).

StyleBuilder

When constructing a complex data structure, such as an SLD document, the use of a Factory is a bit of a pain. That is where StyleBuilder is brought to bare. A Builder is simply a class that help you construct a complicated data structure, for a make involved/interesting example of a builder have a look at the graph package.

Example

The following code example has been borrowed from the geotools website, for additional examples (and advice) please consult the user documentation.

    private Style buildStyle() throws Exception {
        StyleBuilder sb = new StyleBuilder();
        FilterFactory ff = sb.getFilterFactory();
        Style style = sb.createStyle();
        style.setName("MyStyle");

        // "testPoint" feature type style
        Mark testMark = sb.createMark(sb.attributeExpression("name"),
                sb.createFill(Color.RED, 0.5), null);
        Graphic graph = sb.createGraphic(null, new Mark[] { testMark }, null,
                sb.literalExpression(1), sb.attributeExpression("size"),
                sb.attributeExpression("rotation"));
        style.addFeatureTypeStyle(sb.createFeatureTypeStyle("testPoint",
                new Symbolizer[] { sb.createPointSymbolizer(graph) }));

        // "labelPoint" feature type style
        AnchorPoint anchorPoint = sb.createAnchorPoint(sb.attributeExpression("X"),
                sb.attributeExpression("Y"));
        PointPlacement pointPlacement = sb.createPointPlacement(anchorPoint, null,
                sb.literalExpression(0));
        TextSymbolizer textSymbolizer = sb.createTextSymbolizer(sb.createFill(Color.BLACK),
                new Font[] { sb.createFont("Lucida Sans", 10), sb.createFont("Arial", 10) },
                sb.createHalo(), sb.attributeExpression("name"), pointPlacement, null);
        Mark circle = sb.createMark(StyleBuilder.MARK_CIRCLE, Color.RED);
        Graphic graph2 = sb.createGraphic(null, circle, null, 1, 4, 0);
        PointSymbolizer pointSymbolizer = sb.createPointSymbolizer(graph2);
        style.addFeatureTypeStyle(sb.createFeatureTypeStyle("labelPoint",
                new Symbolizer[] { textSymbolizer, pointSymbolizer }));

        return style;
    }

References

The following links will be of interest:

• SLD 1.0.0
• Design Patterns, GOF

Since:

GeoTools 2.0

Author:

Ian Turton, CCG, James Macgill, CCG, Jody Garnett, Refractions Research

Interface Summary

Interface	Description
AnchorPoint	An AnchorPoint identifies the location inside a label or graphic to use as an "anchor" for positioning it relative to a point geometry.
ChannelSelection	The ChannelSelection element specifies the false-color channel selection for a multi-spectral raster source (such as a multi-band satellite-imagery source).
ColorMap	The ColorMap element defines either the colors of a palette-type raster source or the mapping of fixed-numeric pixel values to colors.
ColorMapEntry	A basic interface for objects which can hold color map entries.
ColorReplacement	Apply color replacement to an external graphic.
ContrastEnhancement	The ContrastEnhancement object defines contrast enhancement for a channel of a false-color image or for a color image.
ContrastMethodStrategy	This interface defines the strategy that a ContrastEnhancement will use to execute the ContrastMethod that it has defined.
Description
Displacement	A Displacement gives X and Y offset displacements to use for rendering a text label near a point.
ExtensionSymbolizer	Custom symbolizer support.
Extent	An Extent gives feature/coverage/raster/matrix dimension extent.
ExternalGraphic	Holds a reference to an external graphics file with a URL to its location and its expected MIME type.
ExternalMark	Specify a mark using an image files (svg, png, gif) or using mark index a true type font file.
FeatureTypeConstraint	A FeatureTypeConstraint identifies a specific feature type and supplies filtering.
FeatureTypeStyle	How to style a feature type.
Fill	The Fill object encapsulates the graphical-symbolization parameters for areas of geometries.
Font	A system-independent object for holding SLD font information.
Font.Style	Enumeration of allow font-style values.
Font.Weight	Enumeration of allow font-weight values.
Graphic	A Graphic is a "graphical symbol" with an inherent shape, color(s), and possibly size.
GraphicLegend	Used to represent a Rule (or other construct) in a user interface or legend.
Halo	A Halo fills an extended area outside the glyphs of a rendered textlabel to make it easier to read over a background.
ImageOutline	ImageOutline specifies how individual source rasters in a multi-raster set (such as a set of satellite-image scenes) should be outlined to make the individual-image locations visible.
LabelPlacement	The "LabelPlacement" specifies where and how a text label should be rendered relative to a geometry.
LayerFeatureConstraints	LayerFeatureConstraints define what features and feature types are referenced in a layer.
LinePlacement	The "LinePlacement" specifies where and how a text label should be rendered relative to a line.
LineSymbolizer	A symbolizer describes how a feature should appear on a map.
Mark	A Mark element defines a "shape" which has coloring applied to it.
NamedLayer	A NamedLayer is used to refer to a layer that has a name in a WMS.
NamedStyle	A NamedStyle is used to refer to a style that has a name in a WMS.
OtherText	Allows open ended extensions for text oriented rendering formats.
PointPlacement	A PointPlacement specifies how a text label is positioned relative to a geometric point.
PointSymbolizer	A symbolizer describes how a feature should appear on a map.
PolygonSymbolizer	A symbolizer describes how a polygon feature should appear on a map.
RasterSymbolizer	The RasterSymbolizer describes how to render raster/matrix-coverage data (e.g., satellite photos, DEMs).
RemoteOWS	A RemoteOWS gives a reference to a remote WFS/WCS/other-OWS server.
ResourceLocator	Provides a hook to locate online resources in ExternalGraphic instances.
Rule	A rule is used to attach a condition to, and group, the individual symbolizers used for rendering.
SelectedChannelType	A class to hold Channel information for use in ChannelSelction objects.
ShadedRelief	The ShadedRelief element selects the application of relief shading (or ?
Stroke	The Stroke object encapsulates the graphical-symbolization parameters for linear geometries.
Style	Indicates how geographical content should be displayed (we call this a style for simplicity; in the spec it is called a UserStyle (user-defined style)).
StyledLayer	'StyledLayer' is not part of the SLD 1.0 spec.
StyledLayerDescriptor	Holds styling information (from a StyleLayerDescriptor document).
StyleFactory	Abstract base class for implementing style factories.
StyleFactory2	Abstract base class for implementing style factories.
StyleVisitor	An interface for classes that want to perform operations on a Style hierarchy.
Symbol	This an empty interface for styling symbol objects to implement
Symbolizer	This is the parent interface of all Symbolizers.
TextSymbolizer	A symbolizer describes how a feature should appear on a map.
TextSymbolizer2	Contains label shield hack.
UserLayer	A UserLayer allows a user-defined layer to be built from WFS and WCS data.

Class Summary

Class	Description
AbstractContrastMethodStrategy
AbstractStyleFactory	Abstract base class for implementing style factories.
AbstractStyleVisitor	A basic implementation of the StyleVisitor interface.
AbstractSymbolizer
AnchorPointImpl	Direct implementation of AnchorPoint.
BasicLineStyle	A style object is quite hard to set up, involving fills, strokes, symbolizers and rules.
BasicPolygonStyle	A style object is quite hard to set up, involving fills, strokes, symbolizers and rules.
ChannelSelectionImpl	ChannelSelectionImpl
ColorMapEntryImpl	Default color map entry implementation
ColorMapImpl	A simple implementation of the color map interface.
ColorReplacementImpl	An implementation of ColorReplacement; this is a wrapper around an implementaiton of the "Recode" function as defined by SymbologyEncoding 1.1.
ContrastEnhancementImpl	The ContrastEnhancement object defines contrast enhancement for a channel of a false-color image or for a color image.
DefaultResourceLocator	Default locator for online resources.
DescriptionImpl
DisplacementImpl
ExponentialContrastMethodStrategy
ExtentImpl
ExternalGraphicImpl
ExternalMarkImpl	Default implementation of ExternalMark.
FeatureTypeConstraintImpl
FeatureTypeStyleImpl	Implementation of Feature Type Style; care is taken to ensure everything is mutable.
FillImpl
FontImpl	Provides a Java representation of the Font element of an SLD.
GraphicImpl	Direct implementation of Graphic.
HaloImpl	Direct implementation of Halo.
HistogramContrastMethodStrategy
ImageOutlineImpl
LayerFeatureConstraintsImpl
LinePlacementImpl	Default implementation of LinePlacement.
LineSymbolizerImpl	Provides a representation of a LineSymbolizer in an SLD Document.
LogarithmicContrastMethodStrategy
MarkImpl	Default implementation of Mark.
NamedLayerImpl	Default implementation of named layer.
NamedStyleImpl	A NamedStyle is used to refer to a style that has a name in a WMS.
NormalizeContrastMethodStrategy
OtherTextImpl
OverlapBehavior	OverlapBehavior tells a system how to behave when multiple raster images in a layer overlap each other, for example with satellite-image scenes.
PointPlacementImpl
PointSymbolizerImpl	Provides a Java representation of the PointSymbolizer.
PolygonSymbolizerImpl	Provides a representation of a PolygonSymbolizer in an SLD Document.
RasterSymbolizerImpl	Default implementation of RasterSymbolizer.
RemoteOWSImpl
RuleImpl	Provides the default implementation of Rule.
SelectedChannelTypeImpl	Default implementation of SelectedChannelType.
ShadedReliefImpl	Default implementation of ShadedRelief.
SLD	Utility class that provides static helper methods for common operations on GeoTools styling objects (e.g.
StrokeImpl	Provides a Java representation of the Stroke object in an SLD document.
StyleBuilder	An utility class designed to ease style building with convenience methods.
StyledLayerDescriptorImpl	Holds styling information (from a StyleLayerDescriptor document).
StyledLayerImpl	Default implementation of StyledLayer.
StyleFactoryImpl	Factory for creating Styles.
StyleFactoryImpl2	Factory for creating Styles; based on the GeoAPI StyleFactory interface.
StyleImpl	Implementation of style.
TextSymbolizerImpl	Provides a Java representation of an SLD TextSymbolizer that defines how text symbols should be rendered.
UserLayerImpl	DJB: on inlinefeature support: The inline features also lets you "sort of" make your WMS into a WFS-T.
VendorSymbolizerImpl	ExtensioSymbolizer capturing a vendor specific extension.

Enum Summary

Enum	Description
FeatureTypeStyle.RenderingSelectionOptions
TextSymbolizer.DisplacementMode	DisplacementMode associates an angle with each enum value
TextSymbolizer.GraphicPlacement	GraphicPlacemnts controls the position of the Graphic associated with the label
TextSymbolizer.PolygonAlignOptions	Enumerated options that can be used with polygonAlign.
UomOgcMapping	Defines the Units of Measure (UOMs) specified by the OGC SE standard and their mappings to Java Units defined in javax.measure.unit.

Exception Summary

Exception	Description
StyleFactoryCreationException	An exception that can be thrown by the StyleFactory if it fails to create the implementation of the StyleFactory.