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;
025
026import org.openstreetmap.josm.Main;
027import org.openstreetmap.josm.tools.Utils;
028
029/**
030 * Models the NTv2 Sub Grid within a Grid Shift File
031 *
032 * @author Peter Yuill
033 * Modified for JOSM :
034 * - removed the RandomAccessFile mode (Pieren)
035 * - read grid file by single bytes. Workaround for a bug in some VM not supporting
036 *   file reading by group of 4 bytes from a jar file.
037 */
038public class NTV2SubGrid implements Cloneable, Serializable {
039
040    private String subGridName;
041    private String parentSubGridName;
042    private String created;
043    private String updated;
044    private double minLat;
045    private double maxLat;
046    private double minLon;
047    private double maxLon;
048    private double latInterval;
049    private double lonInterval;
050    private int nodeCount;
051
052    private int lonColumnCount;
053    private int latRowCount;
054    private float[] latShift;
055    private float[] lonShift;
056    private float[] latAccuracy;
057    private float[] lonAccuracy;
058
059    boolean bigEndian;
060    private NTV2SubGrid[] subGrid;
061
062    /**
063     * Construct a Sub Grid from an InputStream, loading the node data into
064     * arrays in this object.
065     *
066     * @param in GridShiftFile InputStream
067     * @param bigEndian is the file bigEndian?
068     * @param loadAccuracy is the node Accuracy data to be loaded?
069     * @throws IOException
070     */
071    public NTV2SubGrid(InputStream in, boolean bigEndian, boolean loadAccuracy) throws IOException {
072        byte[] b8 = new byte[8];
073        byte[] b4 = new byte[4];
074        byte[] b1 = new byte[1];
075        in.read(b8);
076        in.read(b8);
077        subGridName = new String(b8).trim();
078        in.read(b8);
079        in.read(b8);
080        parentSubGridName = new String(b8).trim();
081        in.read(b8);
082        in.read(b8);
083        created = new String(b8);
084        in.read(b8);
085        in.read(b8);
086        updated = new String(b8);
087        in.read(b8);
088        in.read(b8);
089        minLat = NTV2Util.getDouble(b8, bigEndian);
090        in.read(b8);
091        in.read(b8);
092        maxLat = NTV2Util.getDouble(b8, bigEndian);
093        in.read(b8);
094        in.read(b8);
095        minLon = NTV2Util.getDouble(b8, bigEndian);
096        in.read(b8);
097        in.read(b8);
098        maxLon = NTV2Util.getDouble(b8, bigEndian);
099        in.read(b8);
100        in.read(b8);
101        latInterval = NTV2Util.getDouble(b8, bigEndian);
102        in.read(b8);
103        in.read(b8);
104        lonInterval = NTV2Util.getDouble(b8, bigEndian);
105        lonColumnCount = 1 + (int)((maxLon - minLon) / lonInterval);
106        latRowCount = 1 + (int)((maxLat - minLat) / latInterval);
107        in.read(b8);
108        in.read(b8);
109        nodeCount = NTV2Util.getInt(b8, bigEndian);
110        if (nodeCount != lonColumnCount * latRowCount)
111            throw new IllegalStateException("SubGrid " + subGridName + " has inconsistent grid dimesions");
112        latShift = new float[nodeCount];
113        lonShift = new float[nodeCount];
114        if (loadAccuracy) {
115            latAccuracy = new float[nodeCount];
116            lonAccuracy = new float[nodeCount];
117        }
118
119        for (int i = 0; i < nodeCount; i++) {
120            // Read the grid file byte after byte. This is a workaround about a bug in
121            // certain VM which are not able to read byte blocks when the resource file is
122            // in a .jar file (Pieren)
123            in.read(b1); b4[0] = b1[0];
124            in.read(b1); b4[1] = b1[0];
125            in.read(b1); b4[2] = b1[0];
126            in.read(b1); b4[3] = b1[0];
127            latShift[i] = NTV2Util.getFloat(b4, bigEndian);
128            in.read(b1); b4[0] = b1[0];
129            in.read(b1); b4[1] = b1[0];
130            in.read(b1); b4[2] = b1[0];
131            in.read(b1); b4[3] = b1[0];
132            lonShift[i] = NTV2Util.getFloat(b4, bigEndian);
133            in.read(b1); b4[0] = b1[0];
134            in.read(b1); b4[1] = b1[0];
135            in.read(b1); b4[2] = b1[0];
136            in.read(b1); b4[3] = b1[0];
137            if (loadAccuracy) {
138                latAccuracy[i] = NTV2Util.getFloat(b4, bigEndian);
139            }
140            in.read(b1); b4[0] = b1[0];
141            in.read(b1); b4[1] = b1[0];
142            in.read(b1); b4[2] = b1[0];
143            in.read(b1); b4[3] = b1[0];
144            if (loadAccuracy) {
145                lonAccuracy[i] = NTV2Util.getFloat(b4, bigEndian);
146            }
147        }
148    }
149
150    /**
151     * Tests if a specified coordinate is within this Sub Grid
152     * or one of its Sub Grids. If the coordinate is outside
153     * this Sub Grid, null is returned. If the coordinate is
154     * within this Sub Grid, but not within any of its Sub Grids,
155     * this Sub Grid is returned. If the coordinate is within
156     * one of this Sub Grid's Sub Grids, the method is called
157     * recursively on the child Sub Grid.
158     *
159     * @param lon Longitude in Positive West Seconds
160     * @param lat Latitude in Seconds
161     * @return the Sub Grid containing the Coordinate or null
162     */
163    public NTV2SubGrid getSubGridForCoord(double lon, double lat) {
164        if (isCoordWithin(lon, lat)) {
165            if (subGrid == null)
166                return this;
167            else {
168                for (NTV2SubGrid aSubGrid : subGrid) {
169                    if (aSubGrid.isCoordWithin(lon, lat))
170                        return aSubGrid.getSubGridForCoord(lon, lat);
171                }
172                return this;
173            }
174        } else
175            return null;
176    }
177
178    /**
179     * Tests if a specified coordinate is within this Sub Grid.
180     * A coordinate on either outer edge (maximum Latitude or
181     * maximum Longitude) is deemed to be outside the grid.
182     *
183     * @param lon Longitude in Positive West Seconds
184     * @param lat Latitude in Seconds
185     * @return true or false
186     */
187    private boolean isCoordWithin(double lon, double lat) {
188        if ((lon >= minLon) && (lon < maxLon) && (lat >= minLat) && (lat < maxLat))
189            return true;
190        else
191            return false;
192    }
193
194    /**
195     * Bi-Linear interpolation of four nearest node values as described in
196     * 'GDAit Software Architecture Manual' produced by the <a
197     * href='http://www.sli.unimelb.edu.au/gda94'>Geomatics
198     * Department of the University of Melbourne</a>
199     * @param a value at the A node
200     * @param b value at the B node
201     * @param c value at the C node
202     * @param d value at the D node
203     * @param X Longitude factor
204     * @param Y Latitude factor
205     * @return interpolated value
206     */
207    private final double interpolate(float a, float b, float c, float d, double X, double Y) {
208        return a + (((double)b - (double)a) * X) + (((double)c - (double)a) * Y) +
209        (((double)a + (double)d - b - c) * X * Y);
210    }
211
212    /**
213     * Interpolate shift and accuracy values for a coordinate in the 'from' datum
214     * of the GridShiftFile. The algorithm is described in
215     * 'GDAit Software Architecture Manual' produced by the <a
216     * href='http://www.sli.unimelb.edu.au/gda94'>Geomatics
217     * Department of the University of Melbourne</a>
218     * <p>This method is thread safe for both memory based and file based node data.
219     * @param gs GridShift object containing the coordinate to shift and the shift values
220     * @return the GridShift object supplied, with values updated.
221     */
222    public NTV2GridShift interpolateGridShift(NTV2GridShift gs) {
223        int lonIndex = (int)((gs.getLonPositiveWestSeconds() - minLon) / lonInterval);
224        int latIndex = (int)((gs.getLatSeconds() - minLat) / latInterval);
225
226        double X = (gs.getLonPositiveWestSeconds() - (minLon + (lonInterval * lonIndex))) / lonInterval;
227        double Y = (gs.getLatSeconds() - (minLat + (latInterval * latIndex))) / latInterval;
228
229        // Find the nodes at the four corners of the cell
230
231        int indexA = lonIndex + (latIndex * lonColumnCount);
232        int indexB = indexA + 1;
233        int indexC = indexA + lonColumnCount;
234        int indexD = indexC + 1;
235
236        gs.setLonShiftPositiveWestSeconds(interpolate(
237                lonShift[indexA], lonShift[indexB], lonShift[indexC], lonShift[indexD], X, Y));
238
239        gs.setLatShiftSeconds(interpolate(
240                latShift[indexA], latShift[indexB], latShift[indexC], latShift[indexD], X, Y));
241
242        if (lonAccuracy == null) {
243            gs.setLonAccuracyAvailable(false);
244        } else {
245            gs.setLonAccuracyAvailable(true);
246            gs.setLonAccuracySeconds(interpolate(
247                    lonAccuracy[indexA], lonAccuracy[indexB], lonAccuracy[indexC], lonAccuracy[indexD], X, Y));
248        }
249
250        if (latAccuracy == null) {
251            gs.setLatAccuracyAvailable(false);
252        } else {
253            gs.setLatAccuracyAvailable(true);
254            gs.setLatAccuracySeconds(interpolate(
255                    latAccuracy[indexA], latAccuracy[indexB], latAccuracy[indexC], latAccuracy[indexD], X, Y));
256        }
257        return gs;
258    }
259
260    public String getParentSubGridName() {
261        return parentSubGridName;
262    }
263
264    public String getSubGridName() {
265        return subGridName;
266    }
267
268    public int getNodeCount() {
269        return nodeCount;
270    }
271
272    public int getSubGridCount() {
273        return (subGrid == null) ? 0 : subGrid.length;
274    }
275
276    public NTV2SubGrid getSubGrid(int index) {
277        return (subGrid == null) ? null : subGrid[index];
278    }
279
280    /**
281     * Set an array of Sub Grids of this sub grid
282     * @param subGrid
283     */
284    public void setSubGridArray(NTV2SubGrid[] subGrid) {
285        this.subGrid = Utils.copyArray(subGrid);
286    }
287
288    @Override
289    public String toString() {
290        return subGridName;
291    }
292
293    /**
294     * Returns textual details about the sub grid.
295     * @return textual details about the sub grid
296     */
297    public String getDetails() {
298        StringBuffer buf = new StringBuffer("Sub Grid : ");
299        buf.append(subGridName);
300        buf.append("\nParent   : ");
301        buf.append(parentSubGridName);
302        buf.append("\nCreated  : ");
303        buf.append(created);
304        buf.append("\nUpdated  : ");
305        buf.append(updated);
306        buf.append("\nMin Lat  : ");
307        buf.append(minLat);
308        buf.append("\nMax Lat  : ");
309        buf.append(maxLat);
310        buf.append("\nMin Lon  : ");
311        buf.append(minLon);
312        buf.append("\nMax Lon  : ");
313        buf.append(maxLon);
314        buf.append("\nLat Intvl: ");
315        buf.append(latInterval);
316        buf.append("\nLon Intvl: ");
317        buf.append(lonInterval);
318        buf.append("\nNode Cnt : ");
319        buf.append(nodeCount);
320        return buf.toString();
321    }
322
323    /**
324     * Make a deep clone of this Sub Grid
325     */
326    @Override
327    public Object clone() {
328        NTV2SubGrid clone = null;
329        try {
330            clone = (NTV2SubGrid)super.clone();
331            // Do a deep clone of the sub grids
332            if (subGrid != null) {
333                clone.subGrid = new NTV2SubGrid[subGrid.length];
334                for (int i = 0; i < subGrid.length; i++) {
335                    clone.subGrid[i] = (NTV2SubGrid)subGrid[i].clone();
336                }
337            }
338        } catch (CloneNotSupportedException cnse) {
339            Main.warn(cnse);
340        }
341        return clone;
342    }
343    /**
344     * Get maximum latitude value
345     * @return maximum latitude
346     */
347    public double getMaxLat() {
348        return maxLat;
349    }
350
351    /**
352     * Get maximum longitude value
353     * @return maximum longitude
354     */
355    public double getMaxLon() {
356        return maxLon;
357    }
358
359    /**
360     * Get minimum latitude value
361     * @return minimum latitude
362     */
363    public double getMinLat() {
364        return minLat;
365    }
366
367    /**
368     * Get minimum longitude value
369     * @return minimum longitude
370     */
371    public double getMinLon() {
372        return minLon;
373    }
374}