sascha@474: package de.intevation.gnv.math;
sascha@474:
sascha@474: import com.vividsolutions.jts.geom.Coordinate;
sascha@474: import com.vividsolutions.jts.geom.Envelope;
sascha@474:
sascha@474: import com.vividsolutions.jts.index.quadtree.Quadtree;
sascha@474:
sascha@479: import java.awt.Dimension;
sascha@479:
sascha@479: import java.io.Serializable;
sascha@479:
sascha@479: import java.util.Arrays;
sascha@479: import java.util.Collections;
sascha@479: import java.util.List;
sascha@479:
sascha@474: import org.apache.log4j.Logger;
sascha@474:
sascha@474: /**
sascha@474: * @author Sascha L. Teichmann (sascha.teichmann@intevation.de)
sascha@474: */
sascha@474: public class AreaInterpolation
sascha@474: implements Serializable
sascha@474: {
sascha@474: private static Logger log = Logger.getLogger(AreaInterpolation.class);
sascha@474:
sascha@474: protected double [] raster;
sascha@474:
sascha@474: protected int width;
sascha@474: protected int height;
sascha@474:
sascha@474: public AreaInterpolation() {
sascha@474: }
sascha@474:
sascha@474: public int getWidth() {
sascha@474: return width;
sascha@474: }
sascha@474:
sascha@474: public int getHeight() {
sascha@474: return height;
sascha@474: }
sascha@474:
sascha@474: public double [] getRaster() {
sascha@474: return raster;
sascha@474: }
sascha@474:
sascha@474: public boolean interpolate(
sascha@474: List<? extends Point2d> points,
sascha@474: Envelope boundingBox,
sascha@474: Dimension samples,
sascha@474: XYDepth depth
sascha@474: ) {
sascha@482: boolean debug = log.isDebugEnabled();
sascha@482:
sascha@474: if (points == null || points.isEmpty()) {
sascha@482: if (debug) {
sascha@482: log.debug("no points to interpolate");
sascha@482: }
sascha@474: return false;
sascha@474: }
sascha@474:
sascha@474: double [] buffer = Interpolation2D.calculateBuffer(points);
sascha@474: double dxMax = buffer[0];
sascha@474: double dyMax = buffer[1];
sascha@474:
sascha@474: Quadtree spatialIndex = new Quadtree();
sascha@474:
sascha@474: for (int i = points.size()-1; i >= 0; --i) {
sascha@474: Point2d p = points.get(i);
sascha@474: spatialIndex.insert(p.envelope(), p);
sascha@474: }
sascha@474:
sascha@474: int W = samples.width;
sascha@474: int H = samples.height;
sascha@474:
sascha@474: double cellWidth = boundingBox.getWidth() / W;
sascha@474: double cellHeight = boundingBox.getHeight() / H;
sascha@474:
sascha@482: if (debug) {
sascha@482: log.debug("width: " + boundingBox.getWidth());
sascha@482: log.debug("height: " + boundingBox.getHeight());
sascha@482: log.debug("sample width: " + W);
sascha@482: log.debug("sample height: " + H);
sascha@482: log.debug("cell width: " + cellWidth);
sascha@482: log.debug("cell height: " + cellHeight);
sascha@482: log.debug("buffer x: " + dxMax);
sascha@482: log.debug("buffer y: " + dyMax);
sascha@482: }
sascha@482:
sascha@474: Envelope queryBuffer = new Envelope();
sascha@474: Point2d [] neighbors = new Point2d[4];
sascha@474: Coordinate center = new Coordinate();
sascha@474: L1Comparator invL1 = new L1Comparator(center);
sascha@474:
sascha@474: double [] raster = new double[W*H];
sascha@474: Arrays.fill(raster, Double.NaN);
sascha@474:
sascha@482: double minX = boundingBox.getMinX();
sascha@482: double minY = boundingBox.getMinY();
sascha@482:
sascha@474: int row = 0;
sascha@474: for (int j = 0; j < H; ++j, row += W) {
sascha@482: double y = j*cellHeight + 0.5d*cellHeight + minY;
sascha@482: double x = 0.5d*cellWidth + minX;
sascha@474: for (int i = 0; i < W; ++i, x += cellWidth) {
sascha@474: queryBuffer.init(
sascha@474: x - dxMax, x + dxMax,
sascha@474: y - dyMax, y + dyMax);
sascha@474:
sascha@474: List potential = spatialIndex.query(queryBuffer);
sascha@474:
sascha@482: if (potential.size() < 4) {
sascha@474: continue;
sascha@474: }
sascha@474:
sascha@474: center.x = x; center.y = y;
sascha@474: Collections.sort(potential, invL1);
sascha@474:
sascha@474: neighbors[0] = neighbors[1] =
sascha@474: neighbors[2] = neighbors[3] = null;
sascha@474:
sascha@474: int mask = 0;
sascha@474: // reversed order is essential here!
sascha@474: for (int k = potential.size()-1; k >= 0; --k) {
sascha@474: Point2d n = (Point2d)potential.get(k);
sascha@474: int code = n.x > center.x ? 1 : 0;
sascha@474: if (n.y > center.y) code |= 2;
sascha@474: neighbors[code] = n;
sascha@474: mask |= 1 << code;
sascha@474: }
sascha@474:
sascha@474: int numNeighbors = Integer.bitCount(mask);
sascha@474:
sascha@474: // only interpolate if we have all four neighbors
sascha@474: // we do not have any gaps and we are below surface.
sascha@474: if (numNeighbors == 4
sascha@474: && !neighbors[0].hasIGap(neighbors[1])
sascha@474: && !neighbors[1].hasJGap(neighbors[3])
sascha@474: && !neighbors[3].hasIGap(neighbors[2])
sascha@474: && !neighbors[2].hasJGap(neighbors[0])
sascha@474: && depth.depth(center) <= 0d
sascha@474: ) {
sascha@474: double z1 = Interpolation2D.interpolate(
sascha@474: neighbors[0].x, neighbors[0].z,
sascha@474: neighbors[1].x, neighbors[1].z,
sascha@474: center.x);
sascha@474: double z2 = Interpolation2D.interpolate(
sascha@474: neighbors[2].x, neighbors[2].z,
sascha@474: neighbors[3].x, neighbors[3].z,
sascha@474: center.x);
sascha@474: double y1 = Interpolation2D.interpolate(
sascha@474: neighbors[0].x, neighbors[0].y,
sascha@474: neighbors[1].x, neighbors[1].y,
sascha@474: center.x);
sascha@474: double y2 = Interpolation2D.interpolate(
sascha@474: neighbors[2].x, neighbors[2].y,
sascha@474: neighbors[3].x, neighbors[3].y,
sascha@474: center.x);
sascha@474: raster[row+i] = Interpolation2D.interpolate(
sascha@474: y1, z1,
sascha@474: y2, z2,
sascha@474: center.y);
sascha@474: }
sascha@474: }
sascha@474: }
sascha@474:
sascha@474: this.raster = raster;
sascha@474: this.width = W;
sascha@474: this.height = H;
sascha@474:
sascha@474: return true;
sascha@474: }
sascha@474: }
sascha@474: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :