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 */ 020package org.openstreetmap.josm.data.projection.datum; 021 022import java.io.IOException; 023import java.io.InputStream; 024import java.io.Serializable; 025import java.nio.charset.StandardCharsets; 026import java.util.ArrayList; 027import java.util.HashMap; 028import java.util.List; 029import java.util.Map; 030 031import org.openstreetmap.josm.Main; 032 033/** 034 * Models the NTv2 format Grid Shift File and exposes methods to shift 035 * coordinate values using the Sub Grids contained in the file. 036 * <p>The principal reference for the alogrithms used is the 037 * 'GDAit Software Architecture Manual' produced by the <a 038 * href='http://www.sli.unimelb.edu.au/gda94'>Geomatics 039 * Department of the University of Melbourne</a> 040 * <p>This library reads binary NTv2 Grid Shift files in Big Endian 041 * (Canadian standard) or Little Endian (Australian Standard) format. 042 * The older 'Australian' binary format is not supported, only the 043 * official Canadian format, which is now also used for the national 044 * Australian Grid. 045 * <p>Grid Shift files can be read as InputStreams or RandomAccessFiles. 046 * Loading an InputStream places all the required node information 047 * (accuracy data is optional) into heap based Java arrays. This is the 048 * highest perfomance option, and is useful for large volume transformations. 049 * Non-file data sources (eg using an SQL Blob) are also supported through 050 * InputStream. The RandonAccessFile option has a much smaller memory 051 * footprint as only the Sub Grid headers are stored in memory, but 052 * transformation is slower because the file must be read a number of 053 * times for each transformation. 054 * <p>Coordinates may be shifted Forward (ie from and to the Datums specified 055 * in the Grid Shift File header) or Reverse. The reverse transformation 056 * uses an iterative approach to approximate the Grid Shift, as the 057 * precise transformation is based on 'from' datum coordinates. 058 * <p>Coordinates may be specified 059 * either in Seconds using Positive West Longitude (the original NTv2 060 * arrangement) or in decimal Degrees using Positive East Longitude. 061 * 062 * @author Peter Yuill 063 * Modified for JOSM : 064 * - removed the RandomAccessFile mode (Pieren) 065 */ 066public class NTV2GridShiftFile implements Serializable { 067 068 private static final long serialVersionUID = 1L; 069 070 private int overviewHeaderCount; 071 private int subGridHeaderCount; 072 private int subGridCount; 073 private String shiftType; 074 private String version; 075 private String fromEllipsoid = ""; 076 private String toEllipsoid = ""; 077 private double fromSemiMajorAxis; 078 private double fromSemiMinorAxis; 079 private double toSemiMajorAxis; 080 private double toSemiMinorAxis; 081 082 private NTV2SubGrid[] topLevelSubGrid; 083 private NTV2SubGrid lastSubGrid; 084 085 private static void readBytes(InputStream in, byte[] b) throws IOException { 086 if (in.read(b) < b.length) { 087 Main.error("Failed to read expected amount of bytes ("+ b.length +") from stream"); 088 } 089 } 090 091 /** 092 * Load a Grid Shift File from an InputStream. The Grid Shift node 093 * data is stored in Java arrays, which will occupy about the same memory 094 * as the original file with accuracy data included, and about half that 095 * with accuracy data excluded. The size of the Australian national file 096 * is 4.5MB, and the Canadian national file is 13.5MB 097 * <p>The InputStream is closed by this method. 098 * 099 * @param in Grid Shift File InputStream 100 * @param loadAccuracy is Accuracy data to be loaded as well as shift data? 101 * @throws IOException if any I/O error occurs 102 */ 103 public void loadGridShiftFile(InputStream in, boolean loadAccuracy) throws IOException { 104 byte[] b8 = new byte[8]; 105 fromEllipsoid = ""; 106 toEllipsoid = ""; 107 topLevelSubGrid = null; 108 readBytes(in, b8); 109 String overviewHeaderCountId = new String(b8, StandardCharsets.UTF_8); 110 if (!"NUM_OREC".equals(overviewHeaderCountId)) 111 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file"); 112 boolean bigEndian; 113 readBytes(in, b8); 114 overviewHeaderCount = NTV2Util.getIntBE(b8, 0); 115 if (overviewHeaderCount == 11) { 116 bigEndian = true; 117 } else { 118 overviewHeaderCount = NTV2Util.getIntLE(b8, 0); 119 if (overviewHeaderCount == 11) { 120 bigEndian = false; 121 } else 122 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file"); 123 } 124 readBytes(in, b8); 125 readBytes(in, b8); 126 subGridHeaderCount = NTV2Util.getInt(b8, bigEndian); 127 readBytes(in, b8); 128 readBytes(in, b8); 129 subGridCount = NTV2Util.getInt(b8, bigEndian); 130 NTV2SubGrid[] subGrid = new NTV2SubGrid[subGridCount]; 131 readBytes(in, b8); 132 readBytes(in, b8); 133 shiftType = new String(b8, StandardCharsets.UTF_8); 134 readBytes(in, b8); 135 readBytes(in, b8); 136 version = new String(b8, StandardCharsets.UTF_8); 137 readBytes(in, b8); 138 readBytes(in, b8); 139 fromEllipsoid = new String(b8, StandardCharsets.UTF_8); 140 readBytes(in, b8); 141 readBytes(in, b8); 142 toEllipsoid = new String(b8, StandardCharsets.UTF_8); 143 readBytes(in, b8); 144 readBytes(in, b8); 145 fromSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian); 146 readBytes(in, b8); 147 readBytes(in, b8); 148 fromSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian); 149 readBytes(in, b8); 150 readBytes(in, b8); 151 toSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian); 152 readBytes(in, b8); 153 readBytes(in, b8); 154 toSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian); 155 156 for (int i = 0; i < subGridCount; i++) { 157 subGrid[i] = new NTV2SubGrid(in, bigEndian, loadAccuracy); 158 } 159 topLevelSubGrid = createSubGridTree(subGrid); 160 lastSubGrid = topLevelSubGrid[0]; 161 } 162 163 /** 164 * Create a tree of Sub Grids by adding each Sub Grid to its parent (where 165 * it has one), and returning an array of the top level Sub Grids 166 * @param subGrid an array of all Sub Grids 167 * @return an array of top level Sub Grids with lower level Sub Grids set. 168 */ 169 private static NTV2SubGrid[] createSubGridTree(NTV2SubGrid ... subGrid) { 170 int topLevelCount = 0; 171 Map<String, List<NTV2SubGrid>> subGridMap = new HashMap<>(); 172 for (int i = 0; i < subGrid.length; i++) { 173 if ("NONE".equalsIgnoreCase(subGrid[i].getParentSubGridName())) { 174 topLevelCount++; 175 } 176 subGridMap.put(subGrid[i].getSubGridName(), new ArrayList<NTV2SubGrid>()); 177 } 178 NTV2SubGrid[] topLevelSubGrid = new NTV2SubGrid[topLevelCount]; 179 topLevelCount = 0; 180 for (int i = 0; i < subGrid.length; i++) { 181 if ("NONE".equalsIgnoreCase(subGrid[i].getParentSubGridName())) { 182 topLevelSubGrid[topLevelCount++] = subGrid[i]; 183 } else { 184 List<NTV2SubGrid> parent = subGridMap.get(subGrid[i].getParentSubGridName()); 185 parent.add(subGrid[i]); 186 } 187 } 188 NTV2SubGrid[] nullArray = new NTV2SubGrid[0]; 189 for (int i = 0; i < subGrid.length; i++) { 190 List<NTV2SubGrid> subSubGrids = subGridMap.get(subGrid[i].getSubGridName()); 191 if (!subSubGrids.isEmpty()) { 192 NTV2SubGrid[] subGridArray = subSubGrids.toArray(nullArray); 193 subGrid[i].setSubGridArray(subGridArray); 194 } 195 } 196 return topLevelSubGrid; 197 } 198 199 /** 200 * Shift a coordinate in the Forward direction of the Grid Shift File. 201 * 202 * @param gs A GridShift object containing the coordinate to shift 203 * @return True if the coordinate is within a Sub Grid, false if not 204 */ 205 public boolean gridShiftForward(NTV2GridShift gs) { 206 NTV2SubGrid subGrid = null; 207 if (lastSubGrid != null) { 208 // Try the last sub grid first, big chance the coord is still within it 209 subGrid = lastSubGrid.getSubGridForCoord(gs.getLonPositiveWestSeconds(), gs.getLatSeconds()); 210 } 211 if (subGrid == null) { 212 subGrid = getSubGrid(topLevelSubGrid, gs.getLonPositiveWestSeconds(), gs.getLatSeconds()); 213 } 214 if (subGrid == null) { 215 return false; 216 } else { 217 subGrid.interpolateGridShift(gs); 218 gs.setSubGridName(subGrid.getSubGridName()); 219 lastSubGrid = subGrid; 220 return true; 221 } 222 } 223 224 /** 225 * Shift a coordinate in the Reverse direction of the Grid Shift File. 226 * 227 * @param gs A GridShift object containing the coordinate to shift 228 * @return True if the coordinate is within a Sub Grid, false if not 229 */ 230 public boolean gridShiftReverse(NTV2GridShift gs) { 231 // set up the first estimate 232 NTV2GridShift forwardGs = new NTV2GridShift(); 233 forwardGs.setLonPositiveWestSeconds(gs.getLonPositiveWestSeconds()); 234 forwardGs.setLatSeconds(gs.getLatSeconds()); 235 for (int i = 0; i < 4; i++) { 236 if (!gridShiftForward(forwardGs)) 237 return false; 238 forwardGs.setLonPositiveWestSeconds( 239 gs.getLonPositiveWestSeconds() - forwardGs.getLonShiftPositiveWestSeconds()); 240 forwardGs.setLatSeconds(gs.getLatSeconds() - forwardGs.getLatShiftSeconds()); 241 } 242 gs.setLonShiftPositiveWestSeconds(-forwardGs.getLonShiftPositiveWestSeconds()); 243 gs.setLatShiftSeconds(-forwardGs.getLatShiftSeconds()); 244 gs.setLonAccuracyAvailable(forwardGs.isLonAccuracyAvailable()); 245 if (forwardGs.isLonAccuracyAvailable()) { 246 gs.setLonAccuracySeconds(forwardGs.getLonAccuracySeconds()); 247 } 248 gs.setLatAccuracyAvailable(forwardGs.isLatAccuracyAvailable()); 249 if (forwardGs.isLatAccuracyAvailable()) { 250 gs.setLatAccuracySeconds(forwardGs.getLatAccuracySeconds()); 251 } 252 return true; 253 } 254 255 /** 256 * Find the finest SubGrid containing the coordinate, specified in Positive West Seconds 257 * @param topLevelSubGrid top level subgrid 258 * @param lon Longitude in Positive West Seconds 259 * @param lat Latitude in Seconds 260 * @return The SubGrid found or null 261 */ 262 private static NTV2SubGrid getSubGrid(NTV2SubGrid[] topLevelSubGrid, double lon, double lat) { 263 NTV2SubGrid sub = null; 264 for (int i = 0; i < topLevelSubGrid.length; i++) { 265 sub = topLevelSubGrid[i].getSubGridForCoord(lon, lat); 266 if (sub != null) { 267 break; 268 } 269 } 270 return sub; 271 } 272 273 @Override 274 public String toString() { 275 return new StringBuilder(256) 276 .append("Headers : ") 277 .append(overviewHeaderCount) 278 .append("\nSub Hdrs : ") 279 .append(subGridHeaderCount) 280 .append("\nSub Grids: ") 281 .append(subGridCount) 282 .append("\nType : ") 283 .append(shiftType) 284 .append("\nVersion : ") 285 .append(version) 286 .append("\nFr Ellpsd: ") 287 .append(fromEllipsoid) 288 .append("\nTo Ellpsd: ") 289 .append(toEllipsoid) 290 .append("\nFr Maj Ax: ") 291 .append(fromSemiMajorAxis) 292 .append("\nFr Min Ax: ") 293 .append(fromSemiMinorAxis) 294 .append("\nTo Maj Ax: ") 295 .append(toSemiMajorAxis) 296 .append("\nTo Min Ax: ") 297 .append(toSemiMinorAxis) 298 .toString(); 299 } 300 301 public String getFromEllipsoid() { 302 return fromEllipsoid; 303 } 304 305 public String getToEllipsoid() { 306 return toEllipsoid; 307 } 308}