Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/Lines.java @ 4708:45d05402b2a6
Importer: Emit log message when a dry run was run.
author | Felix Wolfsteller <felix.wolfsteller@intevation.de> |
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date | Wed, 19 Dec 2012 11:40:19 +0100 |
parents | ed07dd55f487 |
children |
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package de.intevation.flys.artifacts.geom; import java.util.ArrayList; import java.util.List; import java.util.Iterator; import java.awt.geom.Point2D; import java.awt.geom.Line2D; import de.intevation.flys.artifacts.math.Linear; import org.apache.log4j.Logger; import gnu.trove.TDoubleArrayList; /** * Utility to create lines (intersect water with cross-section etc). */ public class Lines { private static Logger log = Logger.getLogger(Lines.class); public static final double EPSILON = 1e-4; public static enum Mode { UNDEF, WET, DRY }; /** Never instantiate Lines, use static functions instead. */ protected Lines() { } /** * Calculate area of polygon with four vertices. * @return area of polygon with four vertices. */ public static double area(Point2D p1, Point2D p2, Point2D p3, Point2D p4) { double[] x = new double[] {p1.getX(), p2.getX(), p3.getX(), p4.getX(), p1.getX() }; double[] y = new double[] {p1.getY(), p2.getY(), p3.getY(), p4.getY(), p1.getY() }; double area = 0d; for (int i=0; i <4; i++) { area += (x[i] * y[i+1]) - (x[i+1] * y[i]); } return Math.abs(area * 0.5d); } /** * Calculate the 'length' of the given lines. * @param lines lines of which to calculate length. */ public static double length(List<Line2D> lines) { double sum = 0d; for (Line2D line: lines) { double xDiff = line.getX1() - line.getX2(); double yDiff = line.getY1() - line.getY2(); sum += Math.sqrt(xDiff*xDiff + yDiff*yDiff); } return sum; } /** List of lines and a double-precision area. */ private static class ListWithArea { public List<Line2D> lines; public double area; public ListWithArea(List<Line2D> lines, double area) { this.lines = lines; this.area = area; } } /** * For a cross section given as points and a waterlevel (in meters), * create a set of lines that represent the water surface, assuming it * is distributed horizontally equally. * @param points the points describing the river bed. * @param waterLevel the height of the horizontal water line. * @return A list of Lines representing the water surface and the * calculated area between water surface and river bed. */ public static ListWithArea fillWater(List<Point2D> points, double waterLevel) { boolean debug = log.isDebugEnabled(); if (debug) { log.debug("fillWater"); log.debug("----------------------------"); } List<Line2D> result = new ArrayList(); int N = points.size(); if (N == 0) { return new ListWithArea(result, 0d); } if (N == 1) { Point2D p = points.get(0); // Only generate point if over profile if (waterLevel > p.getY()) { result.add(new Line2D.Double( p.getX(), waterLevel, p.getX(), waterLevel)); } // TODO continue calculating area. return new ListWithArea(result, 0d); } double minX = Double.MAX_VALUE; double minY = Double.MAX_VALUE; double maxX = -Double.MAX_VALUE; double maxY = -Double.MAX_VALUE; // To ensure for sequences of equals x's that // the original index order is preserved. for (Point2D p: points) { double x = p.getX(), y = p.getY(); if (x < minX) minX = x; if (x > maxX) maxX = x; if (y < minY) minY = y; if (y > maxY) maxY = y; } if (minY > waterLevel) { // profile completely over water level log.debug("complete over water"); return new ListWithArea(result, 0d); } if (waterLevel > maxY) { // water floods profile log.debug("complete under water"); result.add(new Line2D.Double(minX, waterLevel, maxX, waterLevel)); return new ListWithArea(result, 0d); } // Water is sometimes above, sometimes under profile. Mode mode = Mode.UNDEF; double startX = minX; double area = 0d; // Walking along the profile. for (int i = 1; i < N; ++i) { Point2D p1 = points.get(i-1); Point2D p2 = points.get(i); if (p1.getY() < waterLevel && p2.getY() < waterLevel) { // completely under water if (debug) { log.debug("under water: " + p1 + " " + p2); } if (mode != Mode.WET) { startX = p1.getX(); mode = Mode.WET; } area += area(p1, p2, new Point2D.Double(p2.getX(), waterLevel), new Point2D.Double(p1.getX(), waterLevel)); continue; } // TODO trigger area calculation if (p1.getY() > waterLevel && p2.getY() > waterLevel) { if (debug) { log.debug("over water: " + p1 + " " + p2); } // completely over water if (mode == Mode.WET) { log.debug("over/wet"); result.add(new Line2D.Double( startX, waterLevel, p1.getX(), waterLevel)); } mode = Mode.DRY; continue; } // TODO trigger area calculation if (Math.abs(p1.getX() - p2.getX()) < EPSILON) { // vertical line switch (mode) { case WET: log.debug("vertical/wet"); mode = Mode.DRY; result.add(new Line2D.Double( startX, waterLevel, p1.getX(), waterLevel)); break; case DRY: log.debug("vertical/dry"); mode = Mode.WET; startX = p2.getX(); break; default: // UNDEF log.debug("vertical/undef"); if (p2.getY() < waterLevel) { mode = Mode.WET; startX = p2.getX(); } else { mode = Mode.DRY; } } continue; } // check if waterlevel directly hits the vertices; boolean p1W = Math.abs(waterLevel - p1.getY()) < EPSILON; boolean p2W = Math.abs(waterLevel - p2.getY()) < EPSILON; // TODO trigger area calculation if (p1W || p2W) { if (debug) { log.debug("water hits vertex: " + p1 + " " + p2 + " " + mode); } if (p1W && p2W) { // parallel to water -> dry log.debug("water hits both vertices"); if (mode == Mode.WET) { result.add(new Line2D.Double( startX, waterLevel, p1.getX(), waterLevel)); } mode = Mode.DRY; } else if (p1W) { // p1 == waterlevel log.debug("water hits first vertex"); if (p2.getY() > waterLevel) { // --> dry if (mode == Mode.WET) { result.add(new Line2D.Double( startX, waterLevel, p1.getX(), waterLevel)); } mode = Mode.DRY; } else { // --> wet if (mode != Mode.WET) { startX = p1.getX(); mode = Mode.WET; } area += area(p1, p2, new Point2D.Double(p2.getX(), waterLevel), new Point2D.Double(p2.getX(), waterLevel)); } } else { // p2 == waterlevel log.debug("water hits second vertex"); if (p1.getY() > waterLevel) { // --> wet if (mode != Mode.WET) { startX = p2.getX(); mode = Mode.WET; } } else { // --> dry if (mode == Mode.WET) { result.add(new Line2D.Double( startX, waterLevel, p2.getX(), waterLevel)); } mode = Mode.DRY; area += area(p1, p2, new Point2D.Double(p1.getX(), waterLevel), new Point2D.Double(p1.getX(), waterLevel)); } } if (debug) { log.debug("mode is now: " + mode); } continue; } // TODO trigger area calculation // intersection case double x = Linear.linear( waterLevel, p1.getY(), p2.getY(), p1.getX(), p2.getX()); if (debug) { log.debug("intersection p1:" + p1); log.debug("intersection p2:" + p2); log.debug("intersection at x: " + x); } // Add area of that part of intersection that is 'wet'. if (p1.getY() > waterLevel) { area += area(new Point2D.Double(x, waterLevel), p2, new Point2D.Double(p2.getX(), waterLevel), new Point2D.Double(x, waterLevel)); } else { area += area(new Point2D.Double(x, waterLevel), p1, new Point2D.Double(p1.getX(), waterLevel), new Point2D.Double(x, waterLevel)); } switch (mode) { case WET: log.debug("intersect/wet"); mode = Mode.DRY; result.add(new Line2D.Double( startX, waterLevel, x, waterLevel)); break; case DRY: log.debug("intersect/dry"); mode = Mode.WET; startX = x; break; default: // UNDEF log.debug("intersect/undef"); if (p2.getY() > waterLevel) { log.debug("intersect/undef/over"); mode = Mode.DRY; result.add(new Line2D.Double( p1.getX(), waterLevel, x, waterLevel)); } else { mode = Mode.WET; startX = x; } } // switch mode } // for all points p[i] and p[i-1] if (mode == Mode.WET) { result.add(new Line2D.Double( startX, waterLevel, maxX, waterLevel)); } return new ListWithArea(result, area); } /** * Class holding points that form lines and the calculated length. */ public static class LineData { public double [][] points; public double width; public double area; public LineData(double[][] points, double width, double area) { this.points = points; this.width = width; this.area = area; } } /** Return length of a single line. */ public static double lineLength(Line2D line) { double xDiff = line.getX1() - line.getX2(); double yDiff = line.getY1() - line.getY2(); return Math.sqrt(xDiff*xDiff + yDiff*yDiff); } /** * @param points the riverbed. */ public static LineData createWaterLines( List<Point2D> points, double waterlevel ) { ListWithArea listAndArea = fillWater(points, waterlevel); List<Line2D> lines = listAndArea.lines; TDoubleArrayList lxs = new TDoubleArrayList(); TDoubleArrayList lys = new TDoubleArrayList(); double linesLength = 0.0f; for (Iterator<Line2D> iter = lines.iterator(); iter.hasNext();) { Line2D line = iter.next(); Point2D p1 = line.getP1(); Point2D p2 = line.getP2(); lxs.add(p1.getX()); lys.add(p1.getY()); lxs.add(p2.getX()); lys.add(p2.getY()); // Length calculation. linesLength += lineLength(line); if (iter.hasNext()) { lxs.add(Double.NaN); lys.add(Double.NaN); } } return new LineData( new double [][] { lxs.toNativeArray(), lys.toNativeArray() }, linesLength, listAndArea.area ); } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :