Hi jv,
Below is some demo code that illustrates:
- creating a common feature type with point geometry for location and
an attribute for species status
- creating features and adding them to a feature collection
- creating a rendering style to use different symbols depending on
status value of a feature
- creating a map and displaying it with the JMapFrame.showMap static method
To run this code right now you will need to be using the bleeding edge
GeoTools: 2.6-SNAPSHOT.
Give us some feedback and we can turn more of this into examples and
docs for the GeoTools site.
Michael
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.Point;
import java.awt.Color;
import java.util.HashMap;
import java.util.Map;
import org.geotools.factory.CommonFactoryFinder;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.FeatureCollections;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.geotools.map.DefaultMapContext;
import org.geotools.map.DefaultMapLayer;
import org.geotools.map.MapContext;
import org.geotools.map.MapLayer;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.geotools.styling.FeatureTypeStyle;
import org.geotools.styling.Graphic;
import org.geotools.styling.Mark;
import org.geotools.styling.PointSymbolizer;
import org.geotools.styling.Rule;
import org.geotools.styling.Style;
import org.geotools.styling.StyleBuilder;
import org.geotools.swing.JMapFrame;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.filter.FilterFactory;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
/**
* Demonstrates creating a feature type with a field that will be used to
* control point symbols for rendering the features
*/
public class SpeciesStatus {
public enum Status {
DISAPPEARED(1, Color.BLACK),
SURE(2, Color.GREEN),
UNSURE(3, Color.CYAN),
UNKNOWN(4, Color.GRAY);
/* a map for reverse lookup */
private static Map<Integer, Status> lookup;
static {
lookup = new HashMap<Integer, Status>();
for (Status status : Status.values()) {
lookup.put(status.getCode(), status);
}
}
private int code;
private Color color;
private Status(int code, Color color) {
this.code = code;
this.color = color;
}
public int getCode() {
return code;
}
public Color getColor() {
return color;
}
public static Status get(int code) {
return lookup.get(code);
}
}
private CoordinateReferenceSystem crs;
private SimpleFeatureType featureType;
private SimpleFeatureBuilder featureBuilder;
private GeometryFactory geomFactory;
private FeatureCollection<SimpleFeatureType, SimpleFeature> featureColl;
private Style style;
public SpeciesStatus(CoordinateReferenceSystem crs) {
this.crs = crs;
this.featureColl = FeatureCollections.newCollection();
createFeatureType();
createStyle();
}
private void createFeatureType() {
SimpleFeatureTypeBuilder builder = new SimpleFeatureTypeBuilder();
builder.setName("species_rec");
builder.setCRS(crs);
builder.add("the_geom", Point.class); // geometry field
builder.add("speciesId", String.class); // alpha-numeric ID for species
builder.add("status", Integer.class); // integer status code
featureType = builder.buildFeatureType();
}
/**
* Create a Style with a Rule for each of the Status values
* that we want to render as different symbols
*/
public void createStyle() {
FilterFactory ff = CommonFactoryFinder.getFilterFactory2(null);
StyleBuilder sb = new StyleBuilder();
Rule[] rules = new Rule[Status.values().length];
int k = 0;
for (Status status : Status.values()) {
Graphic graphic = sb.createGraphic();
// remove the default symbol (a bit clunky)
graphic.graphicalSymbols().clear();
// create a new symbol
Mark mark = sb.createMark(StyleBuilder.MARK_CIRCLE,
status.getColor());
graphic.graphicalSymbols().add(mark);
// our point symbolizer to use this symbol
PointSymbolizer sym = sb.createPointSymbolizer(graphic);
// a rule that will select features to render with this status value
Rule rule = sb.createRule(sym);
rule.setFilter(ff.equals(ff.property("status"),
ff.literal(status.getCode())));
rules[k++] = rule;
}
// put all our rules together in a FeatureTypeStyle
FeatureTypeStyle fts =
sb.createFeatureTypeStyle(featureType.getTypeName(), rules);
this.style = sb.createStyle();
style.featureTypeStyles().add(fts);
}
/**
* Add a new feature to out collection
* @param speciesId alpha-numeric species Id
* @param x location X coord (world)
* @param y location Y coord (world)
* @param status the species status category
*/
public void addFeature(String speciesId, double x, double y,
Status status) {
if (geomFactory == null) {
geomFactory = new GeometryFactory();
}
if (featureBuilder == null) {
featureBuilder = new SimpleFeatureBuilder(featureType);
}
Geometry pos = geomFactory.createPoint(new Coordinate(x, y));
featureBuilder.add(pos);
featureBuilder.add(speciesId);
featureBuilder.add(status.getCode());
SimpleFeature feature = featureBuilder.buildFeature(null);
featureColl.add(feature);
}
/**
* Run the demo (args are ignored)
*/
public static void main(String[] args) {
SpeciesStatus me = new SpeciesStatus(DefaultGeographicCRS.WGS84);
me.demo();
}
/**
* Demo: creates a few features with different Status values
* and adds them to the FeaureCollection. Then displays them
* as a map.
*/
private void demo() {
addFeature("lynx", 2.0, 41.0, Status.UNKNOWN);
addFeature("bear", 3.0, 42.0, Status.SURE);
addFeature("bear", 3.5, 41.5, Status.DISAPPEARED);
addFeature("yeti", 2.5, 42.5, Status.UNSURE);
MapContext map = new DefaultMapContext(crs);
map.setTitle("Species status");
MapLayer layer = new DefaultMapLayer(featureColl, style);
map.addLayer(layer);
JMapFrame.showMap(map);
}
}
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