pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / spatial / src / java / org / apache / lucene / spatial / tier / projections / CartesianTierPlotter.java

diff --git a/lucene-java-3.5.0/lucene/contrib/spatial/src/java/org/apache/lucene/spatial/tier/projections/CartesianTierPlotter.java b/lucene-java-3.5.0/lucene/contrib/spatial/src/java/org/apache/lucene/spatial/tier/projections/CartesianTierPlotter.java
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+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.lucene.spatial.tier.projections;
+
+/**
+ * <p><font color="red"><b>NOTE:</b> This API is still in
+ * flux and might change in incompatible ways in the next
+ * release.</font>
+ */
+public class CartesianTierPlotter {
+  public static final String DEFALT_FIELD_PREFIX = "_tier_";
+  
+  final int tierLevel;
+  int tierLength;
+  int tierBoxes;
+  int tierVerticalPosDivider;
+  final IProjector projector;
+  final String fieldPrefix;
+  Double idd = Double.valueOf(180);
+  
+  public CartesianTierPlotter (int tierLevel, IProjector projector, String fieldPrefix) {
+  
+    this.tierLevel  = tierLevel;
+    this.projector = projector;
+    this.fieldPrefix = fieldPrefix;
+    
+    setTierLength();
+    setTierBoxes();
+    setTierVerticalPosDivider();
+  }
+  
+  private void setTierLength (){
+    this.tierLength = (int) Math.pow(2 , this.tierLevel);
+  }
+  
+  private void setTierBoxes () {
+    this.tierBoxes = (int)Math.pow(this.tierLength, 2);
+  }
+  
+  /**
+   * Get nearest max power of 10 greater than
+   * the tierlen
+   * e.g
+   * tierId of 13 has tierLen 8192
+   * nearest max power of 10 greater than tierLen 
+   * would be 10,000
+   */
+  
+  private void setTierVerticalPosDivider() {
+    
+    // ceiling of log base 10 of tierLen
+    
+    tierVerticalPosDivider = Double.valueOf(Math.ceil(
+          Math.log10(Integer.valueOf(this.tierLength).doubleValue()))).intValue();
+    
+    // 
+    tierVerticalPosDivider = (int)Math.pow(10, tierVerticalPosDivider );
+    
+  }
+  
+  public double getTierVerticalPosDivider(){
+    return tierVerticalPosDivider;
+  }
+  
+  /**
+   * TierBoxId is latitude box id + longitude box id
+   * where latitude box id, and longitude box id are transposed in to position
+   * coordinates.
+   * 
+   * @param latitude
+   * @param longitude
+   */
+  public double getTierBoxId (double latitude, double longitude) {
+    
+    double[] coords = projector.coords(latitude, longitude);
+    
+    double id = getBoxId(coords[0]) + (getBoxId(coords[1]) / tierVerticalPosDivider);
+    return id ;
+  }
+  
+  
+  private double getBoxId (double coord){
+    
+    
+    return Math.floor(coord / (idd / this.tierLength));
+  }
+  
+  @SuppressWarnings("unused")
+  private double getBoxId (double coord, int tierLen){
+    return Math.floor(coord / (idd / tierLen) );
+  }
+  /**
+   * get the string name representing current tier
+   * _localTier&lt;tiedId&gt;
+   */
+  public String getTierFieldName (){
+    
+    return fieldPrefix + this.tierLevel;
+  }
+  
+  /**
+   * get the string name representing tierId
+   * _localTier&lt;tierId&gt;
+   * @param tierId
+   */
+  public String getTierFieldName (int tierId){
+    
+    return fieldPrefix + tierId;
+  }
+  
+  /**
+   * Find the tier with the best fit for a bounding box
+   * Best fit is defined as the ceiling of
+   *  log2 (circumference of earth / distance) 
+   *  distance is defined as the smallest box fitting
+   *  the corner between a radius and a bounding box.
+   *  
+   *  Distances less than a mile return 15, finer granularity is
+   *  in accurate
+   */
+  public int bestFit(double miles){
+    
+    //28,892 a rough circumference of the earth
+    int circ = 28892;
+    
+    double r = miles / 2.0;
+    
+    double corner = r - Math.sqrt(Math.pow(r, 2) / 2.0d);
+    double times = circ / corner;
+    int bestFit =  (int)Math.ceil(log2(times)) + 1;
+    
+    if (bestFit > 15) {
+      // 15 is the granularity of about 1 mile
+      // finer granularity isn't accurate with standard java math
+      return 15;
+    }
+    return bestFit;
+  }
+  
+  /**
+   * a log to the base 2 formula
+   * <code>Math.log(value) / Math.log(2)</code>
+   * @param value
+   */
+  public double log2(double value) {
+    
+    return Math.log(value) / Math.log(2);
+  }
+}