2008/11/19 Benoît Thiébault <[EMAIL PROTECTED]>:
> I will have a look at this in more details. Could you please point the
> name of the class you refer to when you talk about vector layer of
> polygons ?
I was simply thinking of a FeatureCollection of polygonal features
which you could create, save to a shapefile or database etc. and then
manipulate and display as required.
Here is some code that I have used to create a regular lattice of
features, each with an integer id and a single double value. No doubt
there is a much easier and more elegant way of doing this :-)
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.Polygon;
import java.awt.geom.Rectangle2D;
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.referencing.CRS;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
public FeatureCollection makeRegularLattice(
Rectangle2D bounds, double cellWidth,
CoordinateReferenceSystem crs) {
int rows = (int)Math.round((bounds.getHeight()) / cellWidth);
int cols = (int)Math.round((bounds.getWidth()) / cellWidth);
double[] xvertices = new double[cols+1];
for (int i = 0; i <= cols; i++) {
xvertices[i] = bounds.getMinX() + i*cellWidth;
}
double[] yvertices = new double[rows+1];
for (int i = 0; i < rows; i++) {
yvertices[i] = bounds.getMinY() + i*cellWidth;
}
SimpleFeatureTypeBuilder typeBuilder = new SimpleFeatureTypeBuilder();
typeBuilder.setName("lattice");
typeBuilder.setCRS(crs);
typeBuilder.add("shape", Polygon.class,
(CoordinateReferenceSystem) null);
typeBuilder.add("id", Integer.class);
typeBuilder.add("somevalue", Double.class);
SimpleFeatureType type = typeBuilder.buildFeatureType();
SimpleFeatureBuilder builder = new SimpleFeatureBuilder(type);
GeometryFactory gf = new GeometryFactory();
Coordinate[] cellVertices = new Coordinate[5];
int[] xind = {0, 1, 1, 0};
int[] yind = {0, 0, 1, 1};
FeatureCollection features = FeatureCollections.newCollection();
int id = 1;
double valuePlaceHolder = 0;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
for (int v = 0; v < 4; v++) {
cellVertices[v] = new Coordinate(xvertices[j +
xind[v]], yvertices[i + yind[v]]);
}
cellVertices[4] = new Coordinate(cellVertices[0]);
Polygon poly =
gf.createPolygon(gf.createLinearRing(cellVertices), null);
builder.add(poly);
builder.add(id++);
builder.add(valuePlaceHolder);
features.add(builder.buildFeature(null));
}
}
return features;
}
Hope this helps
Michael
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