/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2011, Open Source Geospatial Foundation (OSGeo)
* (C) 2001-2007 TOPP - www.openplans.org.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.process.feature.gs;
import java.util.Iterator;
import java.util.logging.Logger;
import javax.measure.converter.UnitConverter;
import javax.measure.unit.SI;
import javax.measure.unit.Unit;
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.measure.Measure;
import org.geotools.process.ProcessException;
import org.geotools.process.factory.DescribeParameter;
import org.geotools.process.factory.DescribeProcess;
import org.geotools.process.factory.DescribeResult;
import org.geotools.process.gs.GSProcess;
import org.geotools.referencing.CRS;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.geotools.util.logging.Logging;
import org.opengis.feature.Feature;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;
import org.opengis.feature.type.FeatureType;
import org.opengis.feature.type.GeometryDescriptor;
import org.opengis.feature.type.PropertyDescriptor;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.MathTransform;
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 com.vividsolutions.jts.operation.distance.DistanceOp;
@DescribeProcess(title = "Nearest", description = "Get nearest feature")
/**
*
*
* @source $URL$
*/
public class NearestProcess implements GSProcess {
private static final Logger LOGGER = Logging.getLogger(NearestProcess.class);
private GeometryFactory geometryFactory = new GeometryFactory();
/**
* Process the input data set.
*
* @param featureCollection
* the data set
* @param crs
* the CRS
* @param point
* the given point
* @return the snapped to feature
* @throws ProcessException
* error
*/
@DescribeResult(name = "result", description = "The nearest feature")
public FeatureCollection execute(
@DescribeParameter(name = "features", description = "The features to search") FeatureCollection featureCollection,
@DescribeParameter(name = "point", description = "The point to search from") Point point,
@DescribeParameter(name = "crs", min = 0, description = "The coordinate reference system of the collection and point (will use the collection one if not provided") CoordinateReferenceSystem crs)
throws ProcessException {
try {
if (crs == null) {
GeometryDescriptor gd = featureCollection.getSchema().getGeometryDescriptor();
if (gd != null) {
crs = gd.getCoordinateReferenceSystem();
}
}
if (crs == null) {
throw new ProcessException(
"The CRS parameter was not provided and the feature collection does not have a default one either");
}
CoordinateReferenceSystem epsg4326;
try {
epsg4326 = CRS.decode("EPSG:4326");
} catch (Exception e) {
throw new ProcessException("Unknown CRS code: EPSG:4326", e);
}
MathTransform crsTransform = CRS.findMathTransform(crs, epsg4326);
FeatureCollection results = FeatureCollections.newCollection();
FeatureType targetFeatureType = createTargetFeatureType(featureCollection.getSchema());
Unit fromUnit = SI.METER;
Unit toUnit = Unit.valueOf("mi");
UnitConverter unitConvert = fromUnit.getConverterTo(toUnit);
Feature nearestFeature = null;
double nearestDistance = 9e9;
double nearestBearing = 0;
Iterator featureIterator = null;
try {
featureIterator = featureCollection.iterator();
while (featureIterator.hasNext()) {
SimpleFeature f = (SimpleFeature) featureIterator.next();
if (f.getDefaultGeometryProperty().getValue() == null)
continue;
DistanceOp op = new DistanceOp(point, (Geometry) f.getDefaultGeometryProperty()
.getValue());
Coordinate[] co = op.closestPoints();
double[] co0 = new double[] { co[0].x, co[0].y, };
double[] co1 = new double[] { co[1].x, co[1].y, };
double[] geo0 = new double[2];
double[] geo1 = new double[2];
crsTransform.transform(co0, 0, geo0, 0, 1);
crsTransform.transform(co1, 0, geo1, 0, 1);
// get distance
Measure m = DefaultGeographicCRS.WGS84.distance(geo0, geo1);
if (m.doubleValue() > nearestDistance)
continue;
nearestFeature = f;
nearestDistance = m.doubleValue();
nearestBearing = calcBearing(co);
}
} finally {
if (featureIterator != null)
featureCollection.close(featureIterator);
}
if (nearestFeature != null) {
nearestDistance = unitConvert.convert(nearestDistance);
results.add(createTargetFeature(nearestFeature,
(SimpleFeatureType) targetFeatureType, nearestDistance, nearestBearing));
}
return results;
} catch (ProcessException e) {
throw e;
} catch (Throwable e) {
LOGGER.warning("Error executing method: " + e);
throw new ProcessException("Error executing method: " + e, e);
}
}
/**
* Create the modified feature type.
*
* @param sourceFeatureType
* the source feature type
* @return the modified feature type
* @throws ProcessException
* errror
*/
private SimpleFeatureType createTargetFeatureType(FeatureType sourceFeatureType)
throws ProcessException {
try {
SimpleFeatureTypeBuilder typeBuilder = new SimpleFeatureTypeBuilder();
typeBuilder.setName(sourceFeatureType.getName().getLocalPart());
typeBuilder.setNamespaceURI(sourceFeatureType.getName().getNamespaceURI());
for (PropertyDescriptor attbType : sourceFeatureType.getDescriptors()) {
typeBuilder.add((AttributeDescriptor) attbType);
}
typeBuilder.minOccurs(1).maxOccurs(1).nillable(false).add("nearest_distance",
Double.class);
typeBuilder.minOccurs(1).maxOccurs(1).nillable(false).add("nearest_bearing",
Double.class);
typeBuilder
.setDefaultGeometry(sourceFeatureType.getGeometryDescriptor().getLocalName());
return typeBuilder.buildFeatureType();
} catch (Exception e) {
LOGGER.warning("Error creating type: " + e);
throw new ProcessException("Error creating type: " + e, e);
}
}
/**
* Create the modified feature.
*
* @param feature
* the source feature
* @param targetFeatureType
* the modified feature type
* @param nearestDistance
* the snap distance
* @param nearestBearing
* the snap bearing
* @return the modified feature
* @throws ProcessException
* error
*/
private SimpleFeature createTargetFeature(Feature feature, SimpleFeatureType targetFeatureType,
Double nearestDistance, Double nearestBearing) throws ProcessException {
try {
AttributeDescriptor distanceAttbType = targetFeatureType
.getDescriptor("nearest_distance");
AttributeDescriptor bearingAttbType = targetFeatureType
.getDescriptor("nearest_bearing");
Object[] attributes = new Object[targetFeatureType.getAttributeCount()];
for (int i = 0; i < attributes.length; i++) {
AttributeDescriptor attbType = targetFeatureType.getAttributeDescriptors().get(i);
if (attbType.equals(distanceAttbType)) {
attributes[i] = nearestDistance;
} else if (attbType.equals(bearingAttbType)) {
attributes[i] = nearestBearing;
} else {
attributes[i] = feature.getProperty(attbType.getName()).getValue();
}
}
return SimpleFeatureBuilder.build(targetFeatureType, attributes, feature
.getIdentifier().getID());
} catch (Exception e) {
LOGGER.warning("Error creating feature: " + e);
throw new ProcessException("Error creating feature: " + e, e);
}
}
/**
* Calculate the bearing between two points.
*
* @param coords
* the points
* @return the bearing
*/
private double calcBearing(Coordinate[] coords) {
double y = Math.sin(coords[1].x - coords[0].x) * Math.cos(coords[1].y);
double x = Math.cos(coords[0].y) * Math.sin(coords[1].y) - Math.sin(coords[0].y)
* Math.cos(coords[1].y) * Math.cos(coords[1].x - coords[0].x);
double brng = ((Math.atan2(y, x) * 180.0 / Math.PI) + 360) % 360;
return brng;
}
}