source: josm/trunk/src/org/openstreetmap/josm/data/projection/datum/NTV2GridShiftFile.java@ 15456

Last change on this file since 15456 was 14273, checked in by stoecker, 6 years ago

fix typos - patch by naoliv - fix #16781 - Thanks a lot
  • Property svn:eol-style set to native
File size: 12.7 KB
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1/*
2 * Copyright (c) 2003 Objectix Pty Ltd All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation.
7 *
8 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
9 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
11 * DISCLAIMED. IN NO EVENT SHALL OBJECTIX PTY LTD BE LIABLE FOR ANY
12 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
13 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
14 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
15 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
16 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
17 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
18 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
19 */
20package org.openstreetmap.josm.data.projection.datum;
21
22import java.io.IOException;
23import java.io.InputStream;
24import java.io.Serializable;
25import java.nio.charset.StandardCharsets;
26import java.util.ArrayList;
27import java.util.HashMap;
28import java.util.List;
29import java.util.Map;
30
31import org.openstreetmap.josm.tools.Logging;
32
33/**
34 * Models the NTv2 format Grid Shift File and exposes methods to shift
35 * coordinate values using the Sub Grids contained in the file.
36 * <p>The principal reference for the algorithms used is the
37 * 'GDAit Software Architecture Manual' produced by the <a
38 * href='http://www.sli.unimelb.edu.au/gda94'>Geomatics
39 * Department of the University of Melbourne</a>
40 * <p>This library reads binary NTv2 Grid Shift files in Big Endian
41 * (Canadian standard) or Little Endian (Australian Standard) format.
42 * The older 'Australian' binary format is not supported, only the
43 * official Canadian format, which is now also used for the national
44 * Australian Grid.
45 * <p>Grid Shift files can be read as InputStreams or RandomAccessFiles.
46 * Loading an InputStream places all the required node information
47 * (accuracy data is optional) into heap based Java arrays. This is the
48 * highest performance option, and is useful for large volume transformations.
49 * Non-file data sources (eg using an SQL Blob) are also supported through
50 * InputStream. The RandonAccessFile option has a much smaller memory
51 * footprint as only the Sub Grid headers are stored in memory, but
52 * transformation is slower because the file must be read a number of
53 * times for each transformation.
54 * <p>Coordinates may be shifted Forward (ie from and to the Datums specified
55 * in the Grid Shift File header) or Reverse. The reverse transformation
56 * uses an iterative approach to approximate the Grid Shift, as the
57 * precise transformation is based on 'from' datum coordinates.
58 * <p>Coordinates may be specified
59 * either in Seconds using Positive West Longitude (the original NTv2
60 * arrangement) or in decimal Degrees using Positive East Longitude.
61 *
62 * @author Peter Yuill
63 * Modified for JOSM :
64 * - removed the RandomAccessFile mode (Pieren)
65 * @since 2507
66 */
67public class NTV2GridShiftFile implements Serializable {
68
69 private static final long serialVersionUID = 1L;
70
71 private int overviewHeaderCount;
72 private int subGridHeaderCount;
73 private int subGridCount;
74 private String shiftType;
75 private String version;
76 private String fromEllipsoid = "";
77 private String toEllipsoid = "";
78 private double fromSemiMajorAxis;
79 private double fromSemiMinorAxis;
80 private double toSemiMajorAxis;
81 private double toSemiMinorAxis;
82
83 private NTV2SubGrid[] topLevelSubGrid;
84 private NTV2SubGrid lastSubGrid;
85
86 private static void readBytes(InputStream in, byte[] b) throws IOException {
87 if (in.read(b) < b.length) {
88 Logging.error("Failed to read expected amount of bytes ("+ b.length +") from stream");
89 }
90 }
91
92 /**
93 * Load a Grid Shift File from an InputStream. The Grid Shift node
94 * data is stored in Java arrays, which will occupy about the same memory
95 * as the original file with accuracy data included, and about half that
96 * with accuracy data excluded. The size of the Australian national file
97 * is 4.5MB, and the Canadian national file is 13.5MB
98 * <p>The InputStream is closed by this method.
99 *
100 * @param in Grid Shift File InputStream
101 * @param loadAccuracy is Accuracy data to be loaded as well as shift data?
102 * @throws IOException if any I/O error occurs
103 */
104 public void loadGridShiftFile(InputStream in, boolean loadAccuracy) throws IOException {
105 byte[] b8 = new byte[8];
106 fromEllipsoid = "";
107 toEllipsoid = "";
108 topLevelSubGrid = null;
109 readBytes(in, b8);
110 String overviewHeaderCountId = new String(b8, StandardCharsets.UTF_8);
111 if (!"NUM_OREC".equals(overviewHeaderCountId))
112 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file");
113 boolean bigEndian;
114 readBytes(in, b8);
115 overviewHeaderCount = NTV2Util.getIntBE(b8, 0);
116 if (overviewHeaderCount == 11) {
117 bigEndian = true;
118 } else {
119 overviewHeaderCount = NTV2Util.getIntLE(b8, 0);
120 if (overviewHeaderCount == 11) {
121 bigEndian = false;
122 } else
123 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file");
124 }
125 readBytes(in, b8);
126 readBytes(in, b8);
127 subGridHeaderCount = NTV2Util.getInt(b8, bigEndian);
128 readBytes(in, b8);
129 readBytes(in, b8);
130 subGridCount = NTV2Util.getInt(b8, bigEndian);
131 NTV2SubGrid[] subGrid = new NTV2SubGrid[subGridCount];
132 readBytes(in, b8);
133 readBytes(in, b8);
134 shiftType = new String(b8, StandardCharsets.UTF_8);
135 readBytes(in, b8);
136 readBytes(in, b8);
137 version = new String(b8, StandardCharsets.UTF_8);
138 readBytes(in, b8);
139 readBytes(in, b8);
140 fromEllipsoid = new String(b8, StandardCharsets.UTF_8);
141 readBytes(in, b8);
142 readBytes(in, b8);
143 toEllipsoid = new String(b8, StandardCharsets.UTF_8);
144 readBytes(in, b8);
145 readBytes(in, b8);
146 fromSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian);
147 readBytes(in, b8);
148 readBytes(in, b8);
149 fromSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian);
150 readBytes(in, b8);
151 readBytes(in, b8);
152 toSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian);
153 readBytes(in, b8);
154 readBytes(in, b8);
155 toSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian);
156
157 for (int i = 0; i < subGridCount; i++) {
158 subGrid[i] = new NTV2SubGrid(in, bigEndian, loadAccuracy);
159 }
160 topLevelSubGrid = createSubGridTree(subGrid);
161 lastSubGrid = topLevelSubGrid[0];
162 }
163
164 /**
165 * Create a tree of Sub Grids by adding each Sub Grid to its parent (where
166 * it has one), and returning an array of the top level Sub Grids
167 * @param subGrid an array of all Sub Grids
168 * @return an array of top level Sub Grids with lower level Sub Grids set.
169 */
170 private static NTV2SubGrid[] createSubGridTree(NTV2SubGrid... subGrid) {
171 int topLevelCount = 0;
172 Map<String, List<NTV2SubGrid>> subGridMap = new HashMap<>();
173 for (int i = 0; i < subGrid.length; i++) {
174 if ("NONE".equalsIgnoreCase(subGrid[i].getParentSubGridName())) {
175 topLevelCount++;
176 }
177 subGridMap.put(subGrid[i].getSubGridName(), new ArrayList<NTV2SubGrid>());
178 }
179 NTV2SubGrid[] topLevelSubGrid = new NTV2SubGrid[topLevelCount];
180 topLevelCount = 0;
181 for (int i = 0; i < subGrid.length; i++) {
182 if ("NONE".equalsIgnoreCase(subGrid[i].getParentSubGridName())) {
183 topLevelSubGrid[topLevelCount++] = subGrid[i];
184 } else {
185 List<NTV2SubGrid> parent = subGridMap.get(subGrid[i].getParentSubGridName());
186 parent.add(subGrid[i]);
187 }
188 }
189 NTV2SubGrid[] nullArray = new NTV2SubGrid[0];
190 for (int i = 0; i < subGrid.length; i++) {
191 List<NTV2SubGrid> subSubGrids = subGridMap.get(subGrid[i].getSubGridName());
192 if (!subSubGrids.isEmpty()) {
193 NTV2SubGrid[] subGridArray = subSubGrids.toArray(nullArray);
194 subGrid[i].setSubGridArray(subGridArray);
195 }
196 }
197 return topLevelSubGrid;
198 }
199
200 /**
201 * Shift a coordinate in the Forward direction of the Grid Shift File.
202 *
203 * @param gs A GridShift object containing the coordinate to shift
204 * @return True if the coordinate is within a Sub Grid, false if not
205 */
206 public boolean gridShiftForward(NTV2GridShift gs) {
207 NTV2SubGrid subGrid = null;
208 if (lastSubGrid != null) {
209 // Try the last sub grid first, big chance the coord is still within it
210 subGrid = lastSubGrid.getSubGridForCoord(gs.getLonPositiveWestSeconds(), gs.getLatSeconds());
211 }
212 if (subGrid == null) {
213 subGrid = getSubGrid(topLevelSubGrid, gs.getLonPositiveWestSeconds(), gs.getLatSeconds());
214 }
215 if (subGrid == null) {
216 return false;
217 } else {
218 subGrid.interpolateGridShift(gs);
219 gs.setSubGridName(subGrid.getSubGridName());
220 lastSubGrid = subGrid;
221 return true;
222 }
223 }
224
225 /**
226 * Shift a coordinate in the Reverse direction of the Grid Shift File.
227 *
228 * @param gs A GridShift object containing the coordinate to shift
229 * @return True if the coordinate is within a Sub Grid, false if not
230 */
231 public boolean gridShiftReverse(NTV2GridShift gs) {
232 // set up the first estimate
233 NTV2GridShift forwardGs = new NTV2GridShift();
234 forwardGs.setLonPositiveWestSeconds(gs.getLonPositiveWestSeconds());
235 forwardGs.setLatSeconds(gs.getLatSeconds());
236 for (int i = 0; i < 4; i++) {
237 if (!gridShiftForward(forwardGs))
238 return false;
239 forwardGs.setLonPositiveWestSeconds(
240 gs.getLonPositiveWestSeconds() - forwardGs.getLonShiftPositiveWestSeconds());
241 forwardGs.setLatSeconds(gs.getLatSeconds() - forwardGs.getLatShiftSeconds());
242 }
243 gs.setLonShiftPositiveWestSeconds(-forwardGs.getLonShiftPositiveWestSeconds());
244 gs.setLatShiftSeconds(-forwardGs.getLatShiftSeconds());
245 gs.setLonAccuracyAvailable(forwardGs.isLonAccuracyAvailable());
246 if (forwardGs.isLonAccuracyAvailable()) {
247 gs.setLonAccuracySeconds(forwardGs.getLonAccuracySeconds());
248 }
249 gs.setLatAccuracyAvailable(forwardGs.isLatAccuracyAvailable());
250 if (forwardGs.isLatAccuracyAvailable()) {
251 gs.setLatAccuracySeconds(forwardGs.getLatAccuracySeconds());
252 }
253 return true;
254 }
255
256 /**
257 * Find the finest SubGrid containing the coordinate, specified in Positive West Seconds
258 * @param topLevelSubGrid top level subgrid
259 * @param lon Longitude in Positive West Seconds
260 * @param lat Latitude in Seconds
261 * @return The SubGrid found or null
262 */
263 private static NTV2SubGrid getSubGrid(NTV2SubGrid[] topLevelSubGrid, double lon, double lat) {
264 NTV2SubGrid sub = null;
265 for (int i = 0; i < topLevelSubGrid.length; i++) {
266 sub = topLevelSubGrid[i].getSubGridForCoord(lon, lat);
267 if (sub != null) {
268 break;
269 }
270 }
271 return sub;
272 }
273
274 @Override
275 public String toString() {
276 return new StringBuilder(256)
277 .append("Headers : ")
278 .append(overviewHeaderCount)
279 .append("\nSub Hdrs : ")
280 .append(subGridHeaderCount)
281 .append("\nSub Grids: ")
282 .append(subGridCount)
283 .append("\nType : ")
284 .append(shiftType)
285 .append("\nVersion : ")
286 .append(version)
287 .append("\nFr Ellpsd: ")
288 .append(fromEllipsoid)
289 .append("\nTo Ellpsd: ")
290 .append(toEllipsoid)
291 .append("\nFr Maj Ax: ")
292 .append(fromSemiMajorAxis)
293 .append("\nFr Min Ax: ")
294 .append(fromSemiMinorAxis)
295 .append("\nTo Maj Ax: ")
296 .append(toSemiMajorAxis)
297 .append("\nTo Min Ax: ")
298 .append(toSemiMinorAxis)
299 .toString();
300 }
301
302 /**
303 * Returns "from" ellipsoid identifier.
304 * @return "from" ellipsoid identifier
305 */
306 public String getFromEllipsoid() {
307 return fromEllipsoid;
308 }
309
310 /**
311 * Returns "to" ellipsoid identifier.
312 * @return "to" ellipsoid identifier
313 */
314 public String getToEllipsoid() {
315 return toEllipsoid;
316 }
317}
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