/there/src/com/google/marvin/there/StreetLocator.java
Java | 429 lines | 254 code | 38 blank | 137 comment | 23 complexity | da703632fa7965fc15433e6c108933c5 MD5 | raw file
1/* 2 * Copyright (C) 2008 Google Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 5 * use this file except in compliance with the License. You may obtain a copy of 6 * the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations under 14 * the License. 15 */ 16package com.google.marvin.there; 17 18import java.io.BufferedReader; 19import java.io.IOException; 20import java.io.InputStream; 21import java.io.InputStreamReader; 22import java.net.HttpURLConnection; 23import java.net.MalformedURLException; 24import java.net.URL; 25import java.util.HashSet; 26 27import org.json.JSONException; 28import org.json.JSONObject; 29 30import android.location.Location; 31import android.location.LocationManager; 32import android.util.Log; 33 34/** 35 * This class implements methods to get street address from lat-lon using 36 * reverse geocoding API through HTTP. 37 * 38 * @author chaitanyag@google.com (Chaitanya Gharpure) 39 */ 40public class StreetLocator { 41 public interface StreetLocatorListener { 42 public void onIntersectionLocated(String[] streetnames); 43 44 public void onAddressLocated(String address); 45 46 public void onFrontBackLocated(String[] streetsFront, String[] streetsBack); 47 } 48 49 private StreetLocatorListener cb; 50 51 private static final String ENCODING = "UTF-8"; 52 53 // URL for obtaining navigation directions 54 private static final String URL_NAV_STRING = "http://maps.google.com/maps/nav?"; 55 // URL for obtaining reverse geocoded location 56 private static final String URL_GEO_STRING = "http://maps.google.com/maps/geo?"; 57 58 public StreetLocator(StreetLocatorListener callback) { 59 cb = callback; 60 } 61 62 /** 63 * Queries the map server and obtains the street names at the specified 64 * location. This is done by obtaining street name at specified location, and 65 * at locations X meters to the N, S, E, and W of the specified location. 66 * 67 * @param lat The latitude in degrees 68 * @param lon The longitude in degrees 69 */ 70 public void getStreetIntersectionAsync(double lat, double lon) { 71 final double latitude = lat; 72 final double longitude = lon; 73 class IntersectionThread implements Runnable { 74 public void run() { 75 cb.onIntersectionLocated(getStreetIntersection(latitude, longitude)); 76 } 77 } 78 (new Thread(new IntersectionThread())).start(); 79 } 80 81 /** 82 * Queries the map server and obtains the street names at the specified 83 * location. This is done by obtaining street name at specified location, and 84 * at locations X meters to the N, S, E, and W of the specified location. 85 * 86 * @param lat The latitude in degrees 87 * @param lon The longitude in degrees 88 */ 89 public void getStreetsInFrontAndBackAsync(double lat, double lon, double heading) { 90 final double latitude = lat; 91 final double longitude = lon; 92 final double direction = heading; 93 class IntersectionThread implements Runnable { 94 public void run() { 95 getStreetsInFrontAndBack(latitude, longitude, direction); 96 } 97 } 98 (new Thread(new IntersectionThread())).start(); 99 } 100 101 102 103 /** 104 * Queries the map server and obtains the reverse geocoded address of the 105 * specified location. 106 * 107 * @param lat The latitude in degrees 108 * @param lon The longitude in degrees 109 */ 110 public void getAddressAsync(double lat, double lon) { 111 final double latitude = lat; 112 final double longitude = lon; 113 class AddressThread implements Runnable { 114 public void run() { 115 cb.onAddressLocated(getAddress(latitude, longitude)); 116 } 117 } 118 (new Thread(new AddressThread())).start(); 119 } 120 121 122 /** 123 * Queries the map server and obtains the street names at the specified 124 * location. This is done by obtaining street name at specified location, and 125 * at locations X meters to the N, S, E, and W of the specified location. 126 * 127 * @param lat The latitude in degrees 128 * @param lon The longitude in degrees 129 * @return Returns the string array containing street names 130 */ 131 public String[] getStreetIntersection(double lat, double lon) { 132 HashSet<String> streets = new HashSet<String>(); 133 try { 134 for (int i = 0; i < 5; i++) { 135 // Find street address at lat-lon x meters to the N, S, E and W of 136 // the given lat-lon 137 String street = parseStreetName(getResult(makeNavURL(lat, lon, lat, lon))); 138 if (street != null) { 139 streets.add(street); 140 } 141 // get points 150m away, towards N, E, S, and W 142 if (i < 4) { 143 Location nextLoc = endLocation(lat, lon, i * 90, 15); 144 lat = nextLoc.getLatitude(); 145 lon = nextLoc.getLongitude(); 146 } 147 } 148 } catch (MalformedURLException mue) { 149 Log.d("Locator", "Malformed URL: " + mue.getMessage()); 150 } catch (IOException e) { 151 Log.d("Locator", "Error reading from Map server: " + e.toString()); 152 } catch (JSONException e) { 153 Log.d("Locator", "Error in JSON response: " + e.getMessage()); 154 } 155 String[] st = new String[streets.size()]; 156 int i = 0; 157 for (String s : streets) { 158 st[i++] = s; 159 } 160 return st; 161 } 162 163 164 165 /** 166 * Queries the map server and obtains the street names at the specified 167 * location. This is done by obtaining street name at specified location, and 168 * at locations X meters to the N, S, E, and W of the specified location. 169 * 170 * @param lat The latitude in degrees 171 * @param lon The longitude in degrees 172 */ 173 public void getStreetsInFrontAndBack(double lat, double lon, double heading) { 174 HashSet<String> streetsFront = new HashSet<String>(); 175 HashSet<String> streetsBack = new HashSet<String>(); 176 double searchDistance = 15; // 15m (? - is there really a factor of 10 here) 177 178 try { 179 // Get the current street 180 String street = parseStreetName(getResult(makeNavURL(lat, lon, lat, lon))); 181 if (street != null) { 182 streetsFront.add(street); 183 streetsBack.add(street); 184 } 185 Log.i("Current street", "lat: " + Double.toString(lat) + ", lon: " + Double.toString(lon)); 186 187 // Get the street in front of the current street 188 Location nextLoc = endLocation(lat, lon, heading, searchDistance); 189 lat = nextLoc.getLatitude(); 190 lon = nextLoc.getLongitude(); 191 street = parseStreetName(getResult(makeNavURL(lat, lon, lat, lon))); 192 if (street != null) { 193 streetsFront.add(street); 194 } 195 Log.i("Front street", "lat: " + Double.toString(lat) + ", lon: " + Double.toString(lon)); 196 197 198 // Get the street behind the current street 199 heading = heading + 180; 200 if (heading >= 360){ 201 heading = heading - 360; 202 } 203 nextLoc = endLocation(lat, lon, heading, searchDistance); 204 lat = nextLoc.getLatitude(); 205 lon = nextLoc.getLongitude(); 206 street = parseStreetName(getResult(makeNavURL(lat, lon, lat, lon))); 207 if (street != null) { 208 streetsBack.add(street); 209 } 210 Log.i("Back street", "lat: " + Double.toString(lat) + ", lon: " + Double.toString(lon)); 211 212 String[] sf = new String[streetsFront.size()]; 213 int i = 0; 214 for (String s : streetsFront) { 215 sf[i++] = s; 216 } 217 218 String[] sb = new String[streetsBack.size()]; 219 i = 0; 220 for (String s : streetsBack) { 221 sb[i++] = s; 222 } 223 cb.onFrontBackLocated(sf, sb); 224 } catch (MalformedURLException e) { 225 // TODO Auto-generated catch block 226 e.printStackTrace(); 227 } catch (JSONException e) { 228 // TODO Auto-generated catch block 229 e.printStackTrace(); 230 } catch (IOException e) { 231 // TODO Auto-generated catch block 232 e.printStackTrace(); 233 } 234 } 235 236 237 238 /** 239 * Queries the map server and obtains the reverse geocoded address of the 240 * specified location. 241 * 242 * @param lat The latitude in degrees 243 * @param lon The longitude in degrees 244 * @return Returns the reverse geocoded address 245 */ 246 public String getAddress(double lat, double lon) { 247 try { 248 String resp = getResult(makeGeoURL(lat, lon)); 249 JSONObject jsonObj = new JSONObject(resp); 250 int code = jsonObj.getJSONObject("Status").getInt("code"); 251 if (code == 200) { 252 return extendShorts(jsonObj.getJSONArray("Placemark").getJSONObject(0).getString("address")); 253 } 254 } catch (MalformedURLException mue) { 255 Log.d("Locator", "Malformed URL: " + mue.getMessage()); 256 } catch (IOException e) { 257 Log.d("Locator", "Error reading from Map server: " + e.toString()); 258 } catch (JSONException e) { 259 Log.d("Locator", "Error in JSON response: " + e.getMessage()); 260 } 261 return null; 262 } 263 264 /** 265 * Parses the JSON response to extract the street name. 266 * 267 * @param resp The String representation of the JSON response 268 * @return Returns the street name 269 * @throws JSONException 270 */ 271 private String parseStreetName(String resp) throws JSONException { 272 JSONObject jsonObj = new JSONObject(resp); 273 int code = jsonObj.getJSONObject("Status").getInt("code"); 274 if (code == 200) { 275 return extendShorts(jsonObj.getJSONArray("Placemark").getJSONObject(0).getString("address")); 276 } 277 return null; 278 } 279 280 /** 281 * Sends a request to the specified URL and obtains the result from the sever. 282 * 283 * @param url The URL to connect to 284 * @return the server response 285 * @throws IOException 286 */ 287 private String getResult(URL url) throws IOException { 288 Log.d("Locator", url.toString()); 289 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 290 conn.setDoInput(true); 291 conn.setDoOutput(true); 292 InputStream is = conn.getInputStream(); 293 String result = toString(is); 294 return result; 295 } 296 297 /** 298 * Prepares the URL to connect to navigation server, from the specified start 299 * and end location coordinates 300 * 301 * @param lat1 Start location latitude in degrees 302 * @param lon1 Start location longitude in degrees 303 * @param lat2 End location latitude in degrees 304 * @param lon2 End location longitude in degrees 305 * @return a well-formed URL 306 * @throws MalformedURLException 307 */ 308 private URL makeNavURL(double lat1, double lon1, double lat2, double lon2) 309 throws MalformedURLException { 310 StringBuilder url = new StringBuilder(); 311 url.append(URL_NAV_STRING).append("hl=EN&gl=EN&output=js&oe=utf8&q=from%3A").append(lat1) 312 .append(",").append(lon1).append("+to%3A").append(lat2).append(",").append(lon2); 313 return new URL(url.toString()); 314 } 315 316 /** 317 * Prepares the URL to connect to the reverse geocoding server from the 318 * specified location coordinates. 319 * 320 * @param lat latitude in degrees of the location to reverse geocode 321 * @param lon longitude in degrees of the location to reverse geocode 322 * @return URL The Geo URL created based on the given lat/lon 323 * @throws MalformedURLException 324 */ 325 private URL makeGeoURL(double lat, double lon) throws MalformedURLException { 326 StringBuilder url = new StringBuilder(); 327 url.append(URL_GEO_STRING).append("q=").append(lat).append(",").append(lon); 328 return new URL(url.toString()); 329 } 330 331 /** 332 * Reads an InputStream and returns its contents as a String. 333 * 334 * @param inputStream The InputStream to read from. 335 * @return The contents of the InputStream as a String. 336 */ 337 private static String toString(InputStream inputStream) throws IOException { 338 StringBuilder outputBuilder = new StringBuilder(); 339 String string; 340 if (inputStream != null) { 341 BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, ENCODING)); 342 while (null != (string = reader.readLine())) { 343 outputBuilder.append(string).append('\n'); 344 } 345 } 346 return outputBuilder.toString(); 347 } 348 349 /** 350 * Replaces the short forms in the address by their longer forms, so that TTS 351 * speaks the addresses properly 352 * 353 * @param addr The address from which to replace short forms 354 * @return the modified address string 355 */ 356 private String extendShorts(String addr) { 357 addr = addr.replace("St,", "Street"); 358 addr = addr.replace("St.", "Street"); 359 addr = addr.replace("Rd", "Road"); 360 addr = addr.replace("Fwy", "Freeway"); 361 addr = addr.replace("Pkwy", "Parkway"); 362 addr = addr.replace("Blvd", "Boulevard"); 363 addr = addr.replace("Expy", "Expressway"); 364 addr = addr.replace("Ave", "Avenue"); 365 addr = addr.replace("Dr", "Drive"); 366 return addr; 367 } 368 369 /** 370 * Computes the new location at a particular direction and distance from the 371 * specified location using the inverse Vincenti formula. 372 * 373 * @param lat1 latitude of source location in degrees 374 * @param lon1 longitude of source location in degrees 375 * @param brng Direction in degrees wrt source location 376 * @param dist Distance from the source location 377 * @return the new location 378 */ 379 private Location endLocation(double lat1, double lon1, double brng, double dist) { 380 double a = 6378137, b = 6356752.3142, f = 1 / 298.257223563; 381 double s = dist; 382 double alpha1 = Math.toRadians(brng); 383 double sinAlpha1 = Math.sin(alpha1), cosAlpha1 = Math.cos(alpha1); 384 385 double tanU1 = (1 - f) * Math.tan(Math.toRadians(lat1)); 386 double cosU1 = 1 / Math.sqrt((1 + tanU1 * tanU1)), sinU1 = tanU1 * cosU1; 387 double sigma1 = Math.atan2(tanU1, cosAlpha1); 388 double sinAlpha = cosU1 * sinAlpha1; 389 double cosSqAlpha = 1 - sinAlpha * sinAlpha; 390 double uSq = cosSqAlpha * (a * a - b * b) / (b * b); 391 double A = 1 + uSq / 16384 * (4096 + uSq * (-768 + uSq * (320 - 175 * uSq))); 392 double B = uSq / 1024 * (256 + uSq * (-128 + uSq * (74 - 47 * uSq))); 393 394 double sigma = s / (b * A), sigmaP = 2 * Math.PI; 395 double cos2SigmaM = 0, sinSigma = 0, deltaSigma = 0, cosSigma = 0; 396 while (Math.abs(sigma - sigmaP) > 1e-12) { 397 cos2SigmaM = Math.cos(2 * sigma1 + sigma); 398 sinSigma = Math.sin(sigma); 399 cosSigma = Math.cos(sigma); 400 deltaSigma = 401 B 402 * sinSigma 403 * (cos2SigmaM + B 404 / 4 405 * (cosSigma * (-1 + 2 * cos2SigmaM * cos2SigmaM) - B / 6 * cos2SigmaM 406 * (-3 + 4 * sinSigma * sinSigma) * (-3 + 4 * cos2SigmaM * cos2SigmaM))); 407 sigmaP = sigma; 408 sigma = s / (b * A) + deltaSigma; 409 } 410 double tmp = sinU1 * sinSigma - cosU1 * cosSigma * cosAlpha1; 411 double lat2 = 412 Math.atan2(sinU1 * cosSigma + cosU1 * sinSigma * cosAlpha1, (1 - f) 413 * Math.sqrt(sinAlpha * sinAlpha + tmp * tmp)); 414 double lambda = 415 Math.atan2(sinSigma * sinAlpha1, cosU1 * cosSigma - sinU1 * sinSigma * cosAlpha1); 416 double C = f / 16 * cosSqAlpha * (4 + f * (4 - 3 * cosSqAlpha)); 417 double L = 418 lambda 419 - (1 - C) 420 * f 421 * sinAlpha 422 * (sigma + C * sinSigma 423 * (cos2SigmaM + C * cosSigma * (-1 + 2 * cos2SigmaM * cos2SigmaM))); 424 Location l = new Location(LocationManager.GPS_PROVIDER); 425 l.setLatitude(Math.toDegrees(lat2)); 426 l.setLongitude(lon1 + Math.toDegrees(L)); 427 return l; 428 } 429}