001 /* 002 * Copyright (c) 2003 Objectix Pty Ltd All rights reserved. 003 * 004 * This library is free software; you can redistribute it and/or 005 * modify it under the terms of the GNU Lesser General Public 006 * License as published by the Free Software Foundation. 007 * 008 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED 009 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 010 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 011 * DISCLAIMED. IN NO EVENT SHALL OBJECTIX PTY LTD BE LIABLE FOR ANY 012 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 013 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 014 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 015 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 016 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 017 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 018 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 019 */ 020 package org.openstreetmap.josm.data.projection.datum; 021 022 import java.io.IOException; 023 import java.io.InputStream; 024 import java.io.Serializable; 025 import java.util.ArrayList; 026 import java.util.HashMap; 027 028 /** 029 * Models the NTv2 format Grid Shift File and exposes methods to shift 030 * coordinate values using the Sub Grids contained in the file. 031 * <p>The principal reference for the alogrithms used is the 032 * 'GDAit Software Architecture Manual' produced by the <a 033 * href='http://www.sli.unimelb.edu.au/gda94'>Geomatics 034 * Department of the University of Melbourne</a> 035 * <p>This library reads binary NTv2 Grid Shift files in Big Endian 036 * (Canadian standard) or Little Endian (Australian Standard) format. 037 * The older 'Australian' binary format is not supported, only the 038 * official Canadian format, which is now also used for the national 039 * Australian Grid. 040 * <p>Grid Shift files can be read as InputStreams or RandomAccessFiles. 041 * Loading an InputStream places all the required node information 042 * (accuracy data is optional) into heap based Java arrays. This is the 043 * highest perfomance option, and is useful for large volume transformations. 044 * Non-file data sources (eg using an SQL Blob) are also supported through 045 * InputStream. The RandonAccessFile option has a much smaller memory 046 * footprint as only the Sub Grid headers are stored in memory, but 047 * transformation is slower because the file must be read a number of 048 * times for each transformation. 049 * <p>Coordinates may be shifted Forward (ie from and to the Datums specified 050 * in the Grid Shift File header) or Reverse. The reverse transformation 051 * uses an iterative approach to approximate the Grid Shift, as the 052 * precise transformation is based on 'from' datum coordinates. 053 * <p>Coordinates may be specified 054 * either in Seconds using Positive West Longitude (the original NTv2 055 * arrangement) or in decimal Degrees using Positive East Longitude. 056 * 057 * @author Peter Yuill 058 * Modifified for JOSM : 059 * - removed the RandomAccessFile mode (Pieren) 060 */ 061 public class NTV2GridShiftFile implements Serializable { 062 063 private String overviewHeaderCountId; 064 private int overviewHeaderCount; 065 private int subGridHeaderCount; 066 private int subGridCount; 067 private String shiftType; 068 private String version; 069 private String fromEllipsoid = ""; 070 private String toEllipsoid = ""; 071 private double fromSemiMajorAxis; 072 private double fromSemiMinorAxis; 073 private double toSemiMajorAxis; 074 private double toSemiMinorAxis; 075 076 private NTV2SubGrid[] topLevelSubGrid; 077 private NTV2SubGrid lastSubGrid; 078 079 public NTV2GridShiftFile() { 080 } 081 082 /** 083 * Load a Grid Shift File from an InputStream. The Grid Shift node 084 * data is stored in Java arrays, which will occupy about the same memory 085 * as the original file with accuracy data included, and about half that 086 * with accuracy data excluded. The size of the Australian national file 087 * is 4.5MB, and the Canadian national file is 13.5MB 088 * <p>The InputStream is closed by this method. 089 * 090 * @param in Grid Shift File InputStream 091 * @param loadAccuracy is Accuracy data to be loaded as well as shift data? 092 * @throws Exception 093 */ 094 public void loadGridShiftFile(InputStream in, boolean loadAccuracy ) throws IOException { 095 byte[] b8 = new byte[8]; 096 boolean bigEndian = true; 097 fromEllipsoid = ""; 098 toEllipsoid = ""; 099 topLevelSubGrid = null; 100 in.read(b8); 101 overviewHeaderCountId = new String(b8); 102 if (!"NUM_OREC".equals(overviewHeaderCountId)) 103 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file"); 104 in.read(b8); 105 overviewHeaderCount = NTV2Util.getIntBE(b8, 0); 106 if (overviewHeaderCount == 11) { 107 bigEndian = true; 108 } else { 109 overviewHeaderCount = NTV2Util.getIntLE(b8, 0); 110 if (overviewHeaderCount == 11) { 111 bigEndian = false; 112 } else 113 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file"); 114 } 115 in.read(b8); 116 in.read(b8); 117 subGridHeaderCount = NTV2Util.getInt(b8, bigEndian); 118 in.read(b8); 119 in.read(b8); 120 subGridCount = NTV2Util.getInt(b8, bigEndian); 121 NTV2SubGrid[] subGrid = new NTV2SubGrid[subGridCount]; 122 in.read(b8); 123 in.read(b8); 124 shiftType = new String(b8); 125 in.read(b8); 126 in.read(b8); 127 version = new String(b8); 128 in.read(b8); 129 in.read(b8); 130 fromEllipsoid = new String(b8); 131 in.read(b8); 132 in.read(b8); 133 toEllipsoid = new String(b8); 134 in.read(b8); 135 in.read(b8); 136 fromSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian); 137 in.read(b8); 138 in.read(b8); 139 fromSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian); 140 in.read(b8); 141 in.read(b8); 142 toSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian); 143 in.read(b8); 144 in.read(b8); 145 toSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian); 146 147 for (int i = 0; i < subGridCount; i++) { 148 subGrid[i] = new NTV2SubGrid(in, bigEndian, loadAccuracy); 149 } 150 topLevelSubGrid = createSubGridTree(subGrid); 151 lastSubGrid = topLevelSubGrid[0]; 152 153 in.close(); 154 } 155 156 /** 157 * Create a tree of Sub Grids by adding each Sub Grid to its parent (where 158 * it has one), and returning an array of the top level Sub Grids 159 * @param subGrid an array of all Sub Grids 160 * @return an array of top level Sub Grids with lower level Sub Grids set. 161 */ 162 private NTV2SubGrid[] createSubGridTree(NTV2SubGrid[] subGrid) { 163 int topLevelCount = 0; 164 HashMap<String, ArrayList<NTV2SubGrid>> subGridMap = new HashMap<String, ArrayList<NTV2SubGrid>>(); 165 for (int i = 0; i < subGrid.length; i++) { 166 if (subGrid[i].getParentSubGridName().equalsIgnoreCase("NONE")) { 167 topLevelCount++; 168 } 169 subGridMap.put(subGrid[i].getSubGridName(), new ArrayList<NTV2SubGrid>()); 170 } 171 NTV2SubGrid[] topLevelSubGrid = new NTV2SubGrid[topLevelCount]; 172 topLevelCount = 0; 173 for (int i = 0; i < subGrid.length; i++) { 174 if (subGrid[i].getParentSubGridName().equalsIgnoreCase("NONE")) { 175 topLevelSubGrid[topLevelCount++] = subGrid[i]; 176 } else { 177 ArrayList<NTV2SubGrid> parent = subGridMap.get(subGrid[i].getParentSubGridName()); 178 parent.add(subGrid[i]); 179 } 180 } 181 NTV2SubGrid[] nullArray = new NTV2SubGrid[0]; 182 for (int i = 0; i < subGrid.length; i++) { 183 ArrayList<NTV2SubGrid> subSubGrids = subGridMap.get(subGrid[i].getSubGridName()); 184 if (subSubGrids.size() > 0) { 185 NTV2SubGrid[] subGridArray = subSubGrids.toArray(nullArray); 186 subGrid[i].setSubGridArray(subGridArray); 187 } 188 } 189 return topLevelSubGrid; 190 } 191 192 /** 193 * Shift a coordinate in the Forward direction of the Grid Shift File. 194 * 195 * @param gs A GridShift object containing the coordinate to shift 196 * @return True if the coordinate is within a Sub Grid, false if not 197 * @throws IOException 198 */ 199 public boolean gridShiftForward(NTV2GridShift gs) { 200 // Try the last sub grid first, big chance the coord is still within it 201 NTV2SubGrid subGrid = lastSubGrid.getSubGridForCoord(gs.getLonPositiveWestSeconds(), gs.getLatSeconds()); 202 if (subGrid == null) { 203 subGrid = getSubGrid(gs.getLonPositiveWestSeconds(), gs.getLatSeconds()); 204 } 205 if (subGrid == null) 206 return false; 207 else { 208 subGrid.interpolateGridShift(gs); 209 gs.setSubGridName(subGrid.getSubGridName()); 210 lastSubGrid = subGrid; 211 return true; 212 } 213 } 214 215 /** 216 * Shift a coordinate in the Reverse direction of the Grid Shift File. 217 * 218 * @param gs A GridShift object containing the coordinate to shift 219 * @return True if the coordinate is within a Sub Grid, false if not 220 * @throws IOException 221 */ 222 public boolean gridShiftReverse(NTV2GridShift gs) { 223 // set up the first estimate 224 NTV2GridShift forwardGs = new NTV2GridShift(); 225 forwardGs.setLonPositiveWestSeconds(gs.getLonPositiveWestSeconds()); 226 forwardGs.setLatSeconds(gs.getLatSeconds()); 227 for (int i = 0; i < 4; i++) { 228 if (!gridShiftForward(forwardGs)) 229 return false; 230 forwardGs.setLonPositiveWestSeconds( 231 gs.getLonPositiveWestSeconds() - forwardGs.getLonShiftPositiveWestSeconds()); 232 forwardGs.setLatSeconds(gs.getLatSeconds() - forwardGs.getLatShiftSeconds()); 233 } 234 gs.setLonShiftPositiveWestSeconds(-forwardGs.getLonShiftPositiveWestSeconds()); 235 gs.setLatShiftSeconds(-forwardGs.getLatShiftSeconds()); 236 gs.setLonAccuracyAvailable(forwardGs.isLonAccuracyAvailable()); 237 if (forwardGs.isLonAccuracyAvailable()) { 238 gs.setLonAccuracySeconds(forwardGs.getLonAccuracySeconds()); 239 } 240 gs.setLatAccuracyAvailable(forwardGs.isLatAccuracyAvailable()); 241 if (forwardGs.isLatAccuracyAvailable()) { 242 gs.setLatAccuracySeconds(forwardGs.getLatAccuracySeconds()); 243 } 244 return true; 245 } 246 247 /** 248 * Find the finest SubGrid containing the coordinate, specified 249 * in Positive West Seconds 250 * 251 * @param lon Longitude in Positive West Seconds 252 * @param lat Latitude in Seconds 253 * @return The SubGrid found or null 254 */ 255 private NTV2SubGrid getSubGrid(double lon, double lat) { 256 NTV2SubGrid sub = null; 257 for (int i = 0; i < topLevelSubGrid.length; i++) { 258 sub = topLevelSubGrid[i].getSubGridForCoord(lon, lat); 259 if (sub != null) { 260 break; 261 } 262 } 263 return sub; 264 } 265 266 public boolean isLoaded() { 267 return (topLevelSubGrid != null); 268 } 269 270 public void unload() { 271 topLevelSubGrid = null; 272 } 273 274 @Override 275 public String toString() { 276 StringBuffer buf = new StringBuffer("Headers : "); 277 buf.append(overviewHeaderCount); 278 buf.append("\nSub Hdrs : "); 279 buf.append(subGridHeaderCount); 280 buf.append("\nSub Grids: "); 281 buf.append(subGridCount); 282 buf.append("\nType : "); 283 buf.append(shiftType); 284 buf.append("\nVersion : "); 285 buf.append(version); 286 buf.append("\nFr Ellpsd: "); 287 buf.append(fromEllipsoid); 288 buf.append("\nTo Ellpsd: "); 289 buf.append(toEllipsoid); 290 buf.append("\nFr Maj Ax: "); 291 buf.append(fromSemiMajorAxis); 292 buf.append("\nFr Min Ax: "); 293 buf.append(fromSemiMinorAxis); 294 buf.append("\nTo Maj Ax: "); 295 buf.append(toSemiMajorAxis); 296 buf.append("\nTo Min Ax: "); 297 buf.append(toSemiMinorAxis); 298 return buf.toString(); 299 } 300 301 /** 302 * Get a copy of the SubGrid tree for this file. 303 * 304 * @return a deep clone of the current SubGrid tree 305 */ 306 public NTV2SubGrid[] getSubGridTree() { 307 NTV2SubGrid[] clone = new NTV2SubGrid[topLevelSubGrid.length]; 308 for (int i = 0; i < topLevelSubGrid.length; i++) { 309 clone[i] = (NTV2SubGrid)topLevelSubGrid[i].clone(); 310 } 311 return clone; 312 } 313 314 public String getFromEllipsoid() { 315 return fromEllipsoid; 316 } 317 318 public String getToEllipsoid() { 319 return toEllipsoid; 320 } 321 322 }