001// License: GPL. For details, see LICENSE file. 002package org.openstreetmap.josm.tools; 003 004import org.openstreetmap.josm.data.coor.LatLon; 005import org.openstreetmap.josm.data.osm.BBox; 006 007/** 008 * Fast index to look up properties of the earth surface. 009 * 010 * It is expected that there is a relatively slow method to look up the property 011 * for a certain coordinate and that there are larger areas with a uniform 012 * property. 013 * 014 * This index tries to find rectangles with uniform property and caches them. 015 * Rectangles are subdivided, if there are different properties within. 016 * (Up to a maximum level, when the slow method is used again.) 017 * 018 * @param <T> the property (like land/water or nation) 019 */ 020public class GeoPropertyIndex<T> { 021 022 private final int maxLevel; 023 private final GeoProperty<T> geoProp; 024 private final GPLevel<T> root; 025 private GPLevel<T> lastLevelUsed; 026 027 private static final boolean DEBUG = false; 028 029 /** 030 * Create new GeoPropertyIndex. 031 * @param geoProp the input property that should be made faster by this index 032 * @param maxLevel max level 033 */ 034 public GeoPropertyIndex(GeoProperty<T> geoProp, int maxLevel) { 035 this.geoProp = geoProp; 036 this.maxLevel = maxLevel; 037 this.root = new GPLevel<>(0, new BBox(-180, -90, 180, 90), null, this); 038 this.lastLevelUsed = root; 039 } 040 041 /** 042 * Look up the property for a certain point. 043 * This gives the same result as {@link GeoProperty#get(LatLon)}, but 044 * should be faster. 045 * @param ll the point coordinates 046 * @return property value at that point 047 */ 048 public T get(LatLon ll) { 049 return lastLevelUsed.get(ll); 050 } 051 052 /** 053 * Returns the geo property. 054 * @return the geo property 055 * @since 14484 056 */ 057 public final GeoProperty<T> getGeoProperty() { 058 return geoProp; 059 } 060 061 /** 062 * Gets the index of the given coordinate. Only used internally 063 * @param ll The lat/lon coordinate 064 * @param level The scale level 065 * @return The index for that position 066 */ 067 public static int index(LatLon ll, int level) { 068 long noParts = 1L << level; 069 long x = ((long) ((ll.lon() + 180.0) * noParts / 360.0)) & 1; 070 long y = ((long) ((ll.lat() + 90.0) * noParts / 180.0)) & 1; 071 return (int) (2 * x + y); 072 } 073 074 protected static class GPLevel<T> { 075 private final T val; 076 private final int level; 077 private final BBox bbox; 078 private final GPLevel<T> parent; 079 private final GeoPropertyIndex<T> owner; 080 081 // child order by index is sw, nw, se, ne 082 private GPLevel<T>[] children; 083 084 public GPLevel(int level, BBox bbox, GPLevel<T> parent, GeoPropertyIndex<T> owner) { 085 this.level = level; 086 this.bbox = bbox; 087 this.parent = parent; 088 this.owner = owner; 089 this.val = owner.geoProp.get(bbox); 090 } 091 092 public T get(LatLon ll) { 093 if (isInside(ll)) 094 return getBounded(ll); 095 if (DEBUG) System.err.print("up["+level+"]"); 096 return parent != null ? parent.get(ll) : null; 097 } 098 099 private T getBounded(LatLon ll) { 100 if (DEBUG) System.err.print("GPLevel["+level+"]"+bbox+" "); 101 if (!isInside(ll)) { 102 throw new AssertionError("Point "+ll+" should be inside "+bbox); 103 } 104 if (val != null) { 105 if (DEBUG) System.err.println(" hit! "+val); 106 owner.lastLevelUsed = this; 107 return val; 108 } 109 if (level >= owner.maxLevel) { 110 if (DEBUG) System.err.println(" max level reached !"); 111 return owner.geoProp.get(ll); 112 } 113 114 if (children == null) { 115 @SuppressWarnings("unchecked") 116 GPLevel<T>[] tmp = new GPLevel[4]; 117 this.children = tmp; 118 } 119 120 int idx = index(ll, level+1); 121 if (children[idx] == null) { 122 double lon1, lat1; 123 switch (idx) { 124 case 0: 125 lon1 = bbox.getTopLeftLon(); 126 lat1 = bbox.getBottomRightLat(); 127 break; 128 case 1: 129 lon1 = bbox.getTopLeftLon(); 130 lat1 = bbox.getTopLeftLat(); 131 break; 132 case 2: 133 lon1 = bbox.getBottomRightLon(); 134 lat1 = bbox.getBottomRightLat(); 135 break; 136 case 3: 137 lon1 = bbox.getBottomRightLon(); 138 lat1 = bbox.getTopLeftLat(); 139 break; 140 default: 141 throw new AssertionError(); 142 } 143 if (DEBUG) System.err.println(" - new with idx "+idx); 144 LatLon center = bbox.getCenter(); 145 BBox b = new BBox(lon1, lat1, center.lon(), center.lat()); 146 children[idx] = new GPLevel<>(level + 1, b, this, owner); 147 } 148 return children[idx].getBounded(ll); 149 } 150 151 /** 152 * Checks, if a point is inside this tile. 153 * Makes sure, that neighboring tiles do not overlap, i.e. a point exactly 154 * on the border of two tiles must be inside exactly one of the tiles. 155 * @param ll the coordinates of the point 156 * @return true, if it is inside of the box 157 */ 158 boolean isInside(LatLon ll) { 159 return bbox.getTopLeftLon() <= ll.lon() && 160 (ll.lon() < bbox.getBottomRightLon() || (ll.lon() == 180.0 && bbox.getBottomRightLon() == 180.0)) && 161 bbox.getBottomRightLat() <= ll.lat() && 162 (ll.lat() < bbox.getTopLeftLat() || (ll.lat() == 90.0 && bbox.getTopLeftLat() == 90.0)); 163 } 164 165 @Override 166 public String toString() { 167 return "GPLevel [val=" + val + ", level=" + level + ", bbox=" + bbox + ']'; 168 } 169 } 170 171 @Override 172 public String toString() { 173 return "GeoPropertyIndex [maxLevel=" + maxLevel + ", geoProp=" + geoProp + ", root=" + root + ", lastLevelUsed=" 174 + lastLevelUsed + ']'; 175 } 176}