source: josm/trunk/src/org/openstreetmap/josm/data/projection/datum/NTV2GridShiftFile.java@ 10680

Last change on this file since 10680 was 10680, checked in by Don-vip, 8 years ago

sonar - pmd:UseVarargs - Use Varargs
  • Property svn:eol-style set to native
File size: 12.4 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.Main;
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 alogrithms 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 perfomance 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 */
66public class NTV2GridShiftFile implements Serializable {
67
68 private static final long serialVersionUID = 1L;
69
70 private int overviewHeaderCount;
71 private int subGridHeaderCount;
72 private int subGridCount;
73 private String shiftType;
74 private String version;
75 private String fromEllipsoid = "";
76 private String toEllipsoid = "";
77 private double fromSemiMajorAxis;
78 private double fromSemiMinorAxis;
79 private double toSemiMajorAxis;
80 private double toSemiMinorAxis;
81
82 private NTV2SubGrid[] topLevelSubGrid;
83 private NTV2SubGrid lastSubGrid;
84
85 private static void readBytes(InputStream in, byte[] b) throws IOException {
86 if (in.read(b) < b.length) {
87 Main.error("Failed to read expected amount of bytes ("+ b.length +") from stream");
88 }
89 }
90
91 /**
92 * Load a Grid Shift File from an InputStream. The Grid Shift node
93 * data is stored in Java arrays, which will occupy about the same memory
94 * as the original file with accuracy data included, and about half that
95 * with accuracy data excluded. The size of the Australian national file
96 * is 4.5MB, and the Canadian national file is 13.5MB
97 * <p>The InputStream is closed by this method.
98 *
99 * @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}
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