source: josm/trunk/src/org/openstreetmap/josm/data/projection/NTV2GridShiftFile.java@ 2516

Last change on this file since 2516 was 2507, checked in by stoecker, 14 years ago

apply #2989 - patch by pieren - improve lambert projection
File size: 12.4 KB
Line 
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;
21
22import java.io.InputStream;
23import java.io.IOException;
24import java.io.RandomAccessFile;
25import java.io.Serializable;
26import java.util.ArrayList;
27import java.util.HashMap;
28
29/**
30 * Models the NTv2 format Grid Shift File and exposes methods to shift
31 * coordinate values using the Sub Grids contained in the file.
32 * <p>The principal reference for the alogrithms used is the
33 * 'GDAit Software Architecture Manual' produced by the <a
34 * href='http://www.sli.unimelb.edu.au/gda94'>Geomatics
35 * Department of the University of Melbourne</a>
36 * <p>This library reads binary NTv2 Grid Shift files in Big Endian
37 * (Canadian standard) or Little Endian (Australian Standard) format.
38 * The older 'Australian' binary format is not supported, only the
39 * official Canadian format, which is now also used for the national
40 * Australian Grid.
41 * <p>Grid Shift files can be read as InputStreams or RandomAccessFiles.
42 * Loading an InputStream places all the required node information
43 * (accuracy data is optional) into heap based Java arrays. This is the
44 * highest perfomance option, and is useful for large volume transformations.
45 * Non-file data sources (eg using an SQL Blob) are also supported through
46 * InputStream. The RandonAccessFile option has a much smaller memory
47 * footprint as only the Sub Grid headers are stored in memory, but
48 * transformation is slower because the file must be read a number of
49 * times for each transformation.
50 * <p>Coordinates may be shifted Forward (ie from and to the Datums specified
51 * in the Grid Shift File header) or Reverse. The reverse transformation
52 * uses an iterative approach to approximate the Grid Shift, as the
53 * precise transformation is based on 'from' datum coordinates.
54 * <p>Coordinates may be specified
55 * either in Seconds using Positive West Longitude (the original NTv2
56 * arrangement) or in decimal Degrees using Positive East Longitude.
57 *
58 * @author Peter Yuill
59 * Modifified for JOSM :
60 * - removed the RandomAccessFile mode (Pieren)
61 */
62public class NTV2GridShiftFile implements Serializable {
63
64 private static final int REC_SIZE = 16;
65 private String overviewHeaderCountId;
66 private int overviewHeaderCount;
67 private int subGridHeaderCount;
68 private int subGridCount;
69 private String shiftType;
70 private String version;
71 private String fromEllipsoid = "";
72 private String toEllipsoid = "";
73 private double fromSemiMajorAxis;
74 private double fromSemiMinorAxis;
75 private double toSemiMajorAxis;
76 private double toSemiMinorAxis;
77
78 private NTV2SubGrid[] topLevelSubGrid;
79 private NTV2SubGrid lastSubGrid;
80
81 public NTV2GridShiftFile() {
82 }
83
84 /**
85 * Load a Grid Shift File from an InputStream. The Grid Shift node
86 * data is stored in Java arrays, which will occupy about the same memory
87 * as the original file with accuracy data included, and about half that
88 * with accuracy data excluded. The size of the Australian national file
89 * is 4.5MB, and the Canadian national file is 13.5MB
90 * <p>The InputStream is closed by this method.
91 *
92 * @param in Grid Shift File InputStream
93 * @param loadAccuracy is Accuracy data to be loaded as well as shift data?
94 * @throws Exception
95 */
96 public void loadGridShiftFile(InputStream in, boolean loadAccuracy ) throws IOException {
97 byte[] b8 = new byte[8];
98 boolean bigEndian = true;
99 fromEllipsoid = "";
100 toEllipsoid = "";
101 topLevelSubGrid = null;
102 in.read(b8);
103 overviewHeaderCountId = new String(b8);
104 if (!"NUM_OREC".equals(overviewHeaderCountId))
105 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file");
106 in.read(b8);
107 overviewHeaderCount = NTV2Util.getIntBE(b8, 0);
108 if (overviewHeaderCount == 11) {
109 bigEndian = true;
110 } else {
111 overviewHeaderCount = NTV2Util.getIntLE(b8, 0);
112 if (overviewHeaderCount == 11) {
113 bigEndian = false;
114 } else
115 throw new IllegalArgumentException("Input file is not an NTv2 grid shift file");
116 }
117 in.read(b8);
118 in.read(b8);
119 subGridHeaderCount = NTV2Util.getInt(b8, bigEndian);
120 in.read(b8);
121 in.read(b8);
122 subGridCount = NTV2Util.getInt(b8, bigEndian);
123 NTV2SubGrid[] subGrid = new NTV2SubGrid[subGridCount];
124 in.read(b8);
125 in.read(b8);
126 shiftType = new String(b8);
127 in.read(b8);
128 in.read(b8);
129 version = new String(b8);
130 in.read(b8);
131 in.read(b8);
132 fromEllipsoid = new String(b8);
133 in.read(b8);
134 in.read(b8);
135 toEllipsoid = new String(b8);
136 in.read(b8);
137 in.read(b8);
138 fromSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian);
139 in.read(b8);
140 in.read(b8);
141 fromSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian);
142 in.read(b8);
143 in.read(b8);
144 toSemiMajorAxis = NTV2Util.getDouble(b8, bigEndian);
145 in.read(b8);
146 in.read(b8);
147 toSemiMinorAxis = NTV2Util.getDouble(b8, bigEndian);
148
149 for (int i = 0; i < subGridCount; i++) {
150 subGrid[i] = new NTV2SubGrid(in, bigEndian, loadAccuracy);
151 }
152 topLevelSubGrid = createSubGridTree(subGrid);
153 lastSubGrid = topLevelSubGrid[0];
154
155 in.close();
156 }
157
158 /**
159 * Create a tree of Sub Grids by adding each Sub Grid to its parent (where
160 * it has one), and returning an array of the top level Sub Grids
161 * @param subGrid an array of all Sub Grids
162 * @return an array of top level Sub Grids with lower level Sub Grids set.
163 */
164 private NTV2SubGrid[] createSubGridTree(NTV2SubGrid[] subGrid) {
165 int topLevelCount = 0;
166 HashMap<String, ArrayList<NTV2SubGrid>> subGridMap = new HashMap<String, ArrayList<NTV2SubGrid>>();
167 for (int i = 0; i < subGrid.length; i++) {
168 if (subGrid[i].getParentSubGridName().equalsIgnoreCase("NONE")) {
169 topLevelCount++;
170 }
171 subGridMap.put(subGrid[i].getSubGridName(), new ArrayList<NTV2SubGrid>());
172 }
173 NTV2SubGrid[] topLevelSubGrid = new NTV2SubGrid[topLevelCount];
174 topLevelCount = 0;
175 for (int i = 0; i < subGrid.length; i++) {
176 if (subGrid[i].getParentSubGridName().equalsIgnoreCase("NONE")) {
177 topLevelSubGrid[topLevelCount++] = subGrid[i];
178 } else {
179 ArrayList<NTV2SubGrid> parent = subGridMap.get(subGrid[i].getParentSubGridName());
180 parent.add(subGrid[i]);
181 }
182 }
183 NTV2SubGrid[] nullArray = new NTV2SubGrid[0];
184 for (int i = 0; i < subGrid.length; i++) {
185 ArrayList<NTV2SubGrid> subSubGrids = subGridMap.get(subGrid[i].getSubGridName());
186 if (subSubGrids.size() > 0) {
187 NTV2SubGrid[] subGridArray = subSubGrids.toArray(nullArray);
188 subGrid[i].setSubGridArray(subGridArray);
189 }
190 }
191 return topLevelSubGrid;
192 }
193
194 /**
195 * Shift a coordinate in the Forward direction of the Grid Shift File.
196 *
197 * @param gs A GridShift object containing the coordinate to shift
198 * @return True if the coordinate is within a Sub Grid, false if not
199 * @throws IOException
200 */
201 public boolean gridShiftForward(NTV2GridShift gs) {
202 // Try the last sub grid first, big chance the coord is still within it
203 NTV2SubGrid subGrid = lastSubGrid.getSubGridForCoord(gs.getLonPositiveWestSeconds(), gs.getLatSeconds());
204 if (subGrid == null) {
205 subGrid = getSubGrid(gs.getLonPositiveWestSeconds(), gs.getLatSeconds());
206 }
207 if (subGrid == null)
208 return false;
209 else {
210 subGrid.interpolateGridShift(gs);
211 gs.setSubGridName(subGrid.getSubGridName());
212 lastSubGrid = subGrid;
213 return true;
214 }
215 }
216
217 /**
218 * Shift a coordinate in the Reverse direction of the Grid Shift File.
219 *
220 * @param gs A GridShift object containing the coordinate to shift
221 * @return True if the coordinate is within a Sub Grid, false if not
222 * @throws IOException
223 */
224 public boolean gridShiftReverse(NTV2GridShift gs) {
225 // set up the first estimate
226 NTV2GridShift forwardGs = new NTV2GridShift();
227 forwardGs.setLonPositiveWestSeconds(gs.getLonPositiveWestSeconds());
228 forwardGs.setLatSeconds(gs.getLatSeconds());
229 for (int i = 0; i < 4; i++) {
230 if (!gridShiftForward(forwardGs))
231 return false;
232 forwardGs.setLonPositiveWestSeconds(
233 gs.getLonPositiveWestSeconds() - forwardGs.getLonShiftPositiveWestSeconds());
234 forwardGs.setLatSeconds(gs.getLatSeconds() - forwardGs.getLatShiftSeconds());
235 }
236 gs.setLonShiftPositiveWestSeconds(-forwardGs.getLonShiftPositiveWestSeconds());
237 gs.setLatShiftSeconds(-forwardGs.getLatShiftSeconds());
238 gs.setLonAccuracyAvailable(forwardGs.isLonAccuracyAvailable());
239 if (forwardGs.isLonAccuracyAvailable()) {
240 gs.setLonAccuracySeconds(forwardGs.getLonAccuracySeconds());
241 }
242 gs.setLatAccuracyAvailable(forwardGs.isLatAccuracyAvailable());
243 if (forwardGs.isLatAccuracyAvailable()) {
244 gs.setLatAccuracySeconds(forwardGs.getLatAccuracySeconds());
245 }
246 return true;
247 }
248
249 /**
250 * Find the finest SubGrid containing the coordinate, specified
251 * in Positive West Seconds
252 *
253 * @param lon Longitude in Positive West Seconds
254 * @param lat Latitude in Seconds
255 * @return The SubGrid found or null
256 */
257 private NTV2SubGrid getSubGrid(double lon, double lat) {
258 NTV2SubGrid sub = null;
259 for (int i = 0; i < topLevelSubGrid.length; i++) {
260 sub = topLevelSubGrid[i].getSubGridForCoord(lon, lat);
261 if (sub != null) {
262 break;
263 }
264 }
265 return sub;
266 }
267
268 public boolean isLoaded() {
269 return (topLevelSubGrid != null);
270 }
271
272 public void unload() throws IOException {
273 topLevelSubGrid = null;
274 }
275
276 @Override
277 public String toString() {
278 StringBuffer buf = new StringBuffer("Headers : ");
279 buf.append(overviewHeaderCount);
280 buf.append("\nSub Hdrs : ");
281 buf.append(subGridHeaderCount);
282 buf.append("\nSub Grids: ");
283 buf.append(subGridCount);
284 buf.append("\nType : ");
285 buf.append(shiftType);
286 buf.append("\nVersion : ");
287 buf.append(version);
288 buf.append("\nFr Ellpsd: ");
289 buf.append(fromEllipsoid);
290 buf.append("\nTo Ellpsd: ");
291 buf.append(toEllipsoid);
292 buf.append("\nFr Maj Ax: ");
293 buf.append(fromSemiMajorAxis);
294 buf.append("\nFr Min Ax: ");
295 buf.append(fromSemiMinorAxis);
296 buf.append("\nTo Maj Ax: ");
297 buf.append(toSemiMajorAxis);
298 buf.append("\nTo Min Ax: ");
299 buf.append(toSemiMinorAxis);
300 return buf.toString();
301 }
302
303 /**
304 * Get a copy of the SubGrid tree for this file.
305 *
306 * @return a deep clone of the current SubGrid tree
307 */
308 public NTV2SubGrid[] getSubGridTree() {
309 NTV2SubGrid[] clone = new NTV2SubGrid[topLevelSubGrid.length];
310 for (int i = 0; i < topLevelSubGrid.length; i++) {
311 clone[i] = (NTV2SubGrid)topLevelSubGrid[i].clone();
312 }
313 return clone;
314 }
315
316 public String getFromEllipsoid() {
317 return fromEllipsoid;
318 }
319
320 public String getToEllipsoid() {
321 return toEllipsoid;
322 }
323
324}
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