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Revisions

  1. ianturton revised this gist Jul 20, 2016. No changes.
  2. ianturton created this gist May 26, 2015.
    144 changes: 144 additions & 0 deletions Buffer
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,144 @@
    package com.ianturton.cookbook.operations;

    import java.util.List;

    import javax.measure.Measure;
    import javax.measure.quantity.Length;
    import javax.measure.unit.SI;

    import org.geotools.data.DataUtilities;
    import org.geotools.feature.SchemaException;
    import org.geotools.feature.simple.SimpleFeatureBuilder;
    import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
    import org.geotools.geometry.jts.JTS;
    import org.geotools.referencing.CRS;
    import org.geotools.referencing.crs.DefaultGeographicCRS;
    import org.ianturton.cookbook.utilities.GenerateRandomData;
    import org.opengis.feature.GeometryAttribute;
    import org.opengis.feature.simple.SimpleFeature;
    import org.opengis.feature.simple.SimpleFeatureType;
    import org.opengis.geometry.MismatchedDimensionException;
    import org.opengis.referencing.FactoryException;
    import org.opengis.referencing.crs.CoordinateReferenceSystem;
    import org.opengis.referencing.crs.ProjectedCRS;
    import org.opengis.referencing.operation.MathTransform;
    import org.opengis.referencing.operation.TransformException;

    import com.vividsolutions.jts.geom.Geometry;
    import com.vividsolutions.jts.geom.Point;

    /**
    * Take a Linestring in WGS84, convert to a local projection and buffer at 1km
    * then reproject to WGS84 and print.
    *
    *
    * @author ian
    *
    */
    public class Buffer {
    public static void main(String args[]) {
    SimpleFeatureType schema = null;
    try {
    schema = DataUtilities.createType("", "Location",
    "locations:LineString:srid=4326," + // <- the geometry
    // attribute:
    "id:Integer" // a number attribute
    );
    } catch (SchemaException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    return;
    }
    SimpleFeature feature = GenerateRandomData
    .createSimpleLineFeature(schema);
    Buffer buf = new Buffer();
    SimpleFeature out = buf.bufferFeature(feature, Measure.valueOf(1.0, SI.KILOMETER));

    System.out.println(feature.getDefaultGeometry()+"\n"+out.getDefaultGeometry());
    }

    public SimpleFeature bufferFeature(SimpleFeature feature,
    Measure<Double, Length> distance) {
    // extract the geometry
    GeometryAttribute gProp = feature.getDefaultGeometryProperty();
    CoordinateReferenceSystem origCRS = gProp.getDescriptor()
    .getCoordinateReferenceSystem();

    Geometry geom = (Geometry) feature.getDefaultGeometry();
    Geometry pGeom = geom;
    MathTransform toTransform,fromTransform = null;
    // reproject the geometry to a local projection
    if (!(origCRS instanceof ProjectedCRS)) {

    Point c = geom.getCentroid();
    double x = c.getCoordinate().x;
    double y = c.getCoordinate().y;

    String code = "AUTO:42001," + x + "," + y;
    // System.out.println(code);
    CoordinateReferenceSystem auto;
    try {
    auto = CRS.decode(code);
    toTransform = CRS.findMathTransform(
    DefaultGeographicCRS.WGS84, auto);
    fromTransform = CRS.findMathTransform(auto,
    DefaultGeographicCRS.WGS84);
    pGeom = JTS.transform(geom, toTransform);
    } catch (MismatchedDimensionException | TransformException
    | FactoryException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }

    }

    // buffer
    Geometry out = buffer(pGeom, distance.doubleValue(SI.METER));
    Geometry retGeom = out;
    // reproject the geometry to the original projection
    if (!(origCRS instanceof ProjectedCRS)) {
    try {
    retGeom = JTS.transform(out, fromTransform);
    } catch (MismatchedDimensionException | TransformException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }
    // return a new feature containing the geom
    SimpleFeatureType schema = feature.getFeatureType();
    SimpleFeatureTypeBuilder ftBuilder = new SimpleFeatureTypeBuilder();
    ftBuilder.setCRS(origCRS);
    //ftBuilder.setDefaultGeometry("buffer");
    ftBuilder.addAll(schema.getAttributeDescriptors());
    ftBuilder.setName(schema.getName());

    SimpleFeatureType nSchema = ftBuilder.buildFeatureType();
    SimpleFeatureBuilder builder = new SimpleFeatureBuilder(nSchema);
    List<Object> atts = feature.getAttributes();
    for(int i=0;i<atts.size();i++) {
    if(atts.get(i) instanceof Geometry) {
    atts.set(i, retGeom);
    }
    }
    SimpleFeature nFeature = builder.buildFeature(null, atts.toArray() );
    return nFeature;
    }

    /**
    * create a buffer around the geometry, assumes the geometry is in the same
    * units as the distance variable.
    *
    * @param geom
    * a projected geometry.
    * @param dist
    * a distance for the buffer in the same units as the projection.
    * @return
    */
    private Geometry buffer(Geometry geom, double dist) {

    Geometry buffer = geom.buffer(dist);

    return buffer;

    }
    }