Merge pull request #553 from zod/elev-source-cleanup

Cleanup hgt reader

brouter-map-creator/src/main/java/btools/mapcreator/ConvertLidarTile.java

@@ -5,22 +5,26 @@ import java.io.BufferedOutputStream;
 import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.Arrays;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
 public class ConvertLidarTile {
-  public static int NROWS;
+  private static int NROWS;
-  public static int NCOLS;
+  private static int NCOLS;
-  public static int ROW_LENGTH;
 
   public static final short NODATA2 = -32767; // hgt-formats nodata
   public static final short NODATA = Short.MIN_VALUE;
 
-  public static final int SRTM3_ROW_LENGTH = 1200; // number of elevation values per line
+  private static final String HGT_FILE_EXT = ".hgt";
-  public static final int SRTM1_ROW_LENGTH = 3600; //-- New file resolution is 3601x3601
+  private static final int HGT_BORDER_OVERLAP = 1;
+  private static final int HGT_3ASEC_ROWS = 1201; // 3 arc second resolution (90m)
+  private static final int HGT_3ASEC_FILE_SIZE = HGT_3ASEC_ROWS * HGT_3ASEC_ROWS * Short.BYTES;
+  private static final int HGT_1ASEC_ROWS = 3601; // 1 arc second resolution (30m)
 
   static short[] imagePixels;
 
@@ -30,8 +34,8 @@ public class ConvertLidarTile {
       for (; ; ) {
         ZipEntry ze = zis.getNextEntry();
         if (ze == null) break;
-        if (ze.getName().endsWith(".hgt")) {
+        if (ze.getName().toLowerCase().endsWith(HGT_FILE_EXT)) {
-          readHgtFromStream(zis, rowOffset, colOffset, 1200);
+          readHgtFromStream(zis, rowOffset, colOffset, HGT_3ASEC_ROWS);
           return;
         }
       }
@@ -40,20 +44,20 @@ public class ConvertLidarTile {
     }
   }
 
-  private static void readHgtFromStream(InputStream is, int rowOffset, int colOffset, int row_length)
+  private static void readHgtFromStream(InputStream is, int rowOffset, int colOffset, int rowLength)
     throws Exception {
     DataInputStream dis = new DataInputStream(new BufferedInputStream(is));
-    for (int ir = 0; ir < row_length + 1; ir++) {
+    for (int ir = 0; ir < rowLength; ir++) {
       int row = rowOffset + ir;
 
-      for (int ic = 0; ic < row_length + 1; ic++) {
+      for (int ic = 0; ic < rowLength; ic++) {
         int col = colOffset + ic;
 
         int i1 = dis.read(); // msb first!
         int i0 = dis.read();
 
         if (i0 == -1 || i1 == -1)
-          throw new RuntimeException("unexcepted end of file reading hgt entry!");
+          throw new RuntimeException("unexpected end of file reading hgt entry!");
 
         short val = (short) ((i1 << 8) | i0);
 
@@ -191,80 +195,56 @@ public class ConvertLidarTile {
   }
 
   public SrtmRaster getRaster(File f, double lon, double lat) throws Exception {
+    long fileSize;
+    InputStream inputStream;
 
     if (f.getName().toLowerCase().endsWith(".zip")) {
       ZipInputStream zis = new ZipInputStream(new BufferedInputStream(new FileInputStream(f)));
-      try {
       for (; ; ) {
         ZipEntry ze = zis.getNextEntry();
-          if (ze == null) break;
+        if (ze == null) {
-          if (ze.getName().toLowerCase().endsWith(".hgt")) {
+          throw new FileNotFoundException(f.getName() + " doesn't contain a " + HGT_FILE_EXT + " file.");
-            if (ze.getSize() > ((SRTM3_ROW_LENGTH + 1) * (SRTM3_ROW_LENGTH + 1) * 2)) {
-              ROW_LENGTH = SRTM1_ROW_LENGTH;
-            } else {
-              ROW_LENGTH = SRTM3_ROW_LENGTH;
         }
-            // stay a 1x1 raster
+        if (ze.getName().toLowerCase().endsWith(HGT_FILE_EXT)) {
-            NROWS = ROW_LENGTH + 1;
+          fileSize = ze.getSize();
-            NCOLS = ROW_LENGTH + 1;
+          inputStream = zis;
-
-            imagePixels = new short[NROWS * NCOLS]; // 650 MB !
-
-            // prefill as NODATA
-            for (int row = 0; row < NROWS; row++) {
-              for (int col = 0; col < NCOLS; col++) {
-                imagePixels[row * NCOLS + col] = NODATA;
-              }
-            }
-            readHgtFromStream(zis, 0, 0, ROW_LENGTH);
           break;
         }
       }
-      } finally {
-        zis.close();
-      }
     } else {
-      if (f.length() > ((SRTM3_ROW_LENGTH + 1) * (SRTM3_ROW_LENGTH + 1) * 2)) {
+      fileSize = f.length();
-        ROW_LENGTH = SRTM1_ROW_LENGTH;
+      inputStream = new FileInputStream(f);
-      } else {
-        ROW_LENGTH = SRTM3_ROW_LENGTH;
     }
-      // stay a 1x1 raster
-      NROWS = ROW_LENGTH + 1;
-      NCOLS = ROW_LENGTH + 1;
 
-      imagePixels = new short[NROWS * NCOLS]; // 650 MB !
+    int rowLength;
+    if (fileSize > HGT_3ASEC_FILE_SIZE) {
+      rowLength = HGT_1ASEC_ROWS;
+    } else {
+      rowLength = HGT_3ASEC_ROWS;
+    }
+
+    // stay at 1 deg * 1 deg raster
+    NROWS = rowLength;
+    NCOLS = rowLength;
+
+    imagePixels = new short[NROWS * NCOLS];
 
     // prefill as NODATA
-      for (int row = 0; row < NROWS; row++) {
+    Arrays.fill(imagePixels, NODATA);
-        for (int col = 0; col < NCOLS; col++) {
+    readHgtFromStream(inputStream, 0, 0, rowLength);
-          imagePixels[row * NCOLS + col] = NODATA;
+    inputStream.close();
-        }
-      }
-      FileInputStream dis = new FileInputStream(f);
-      try {
-        readHgtFromStream(dis, 0, 0, ROW_LENGTH);
-      } finally {
-        dis.close();
-      }
-    }
-
-    System.out.println("read file " + f + " rl " + ROW_LENGTH);
-    
-    boolean halfCol5 = false; // no halfcol tiles in lidar data (?)
 
     SrtmRaster raster = new SrtmRaster();
     raster.nrows = NROWS;
     raster.ncols = NCOLS;
-    raster.halfcol = halfCol5;
+    raster.halfcol = false; // assume full resolution
     raster.noDataValue = NODATA;
-    raster.cellsize = 1. / (double) ROW_LENGTH;
+    raster.cellsize = 1. / (double) (rowLength - HGT_BORDER_OVERLAP);
     raster.xllcorner = (int) (lon < 0 ? lon - 1 : lon); //onDegreeStart - raster.cellsize;
     raster.yllcorner = (int) (lat < 0 ? lat - 1 : lat); //latDegreeStart - raster.cellsize;
     raster.eval_array = imagePixels;
 
     return raster;
-
   }
 
 }

brouter-map-creator/src/main/java/btools/mapcreator/HgtReader.java

@@ -1,269 +0,0 @@
-// License: GPL. For details, see LICENSE file.
-package btools.mapcreator;
-
-import java.io.BufferedInputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileNotFoundException;
-import java.io.InputStream;
-import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
-import java.nio.ShortBuffer;
-import java.nio.channels.FileChannel;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipInputStream;
-
-/**
- * adapted from https://github.com/JOSM/josm-plugins/blob/master/ElevationProfile/src/org/openstreetmap/josm/plugins/elevation/HgtReader.java
- * <p>
- * Class HgtReader reads data from SRTM HGT files. Currently this class is restricted to a resolution of 3 arc seconds.
- * <p>
- * SRTM data files are available at the <a href="http://dds.cr.usgs.gov/srtm/version2_1/SRTM3">NASA SRTM site</a>
- *
- * @author Oliver Wieland &lt;oliver.wieland@online.de&gt;
- */
-public class HgtReader {
-  final static boolean DEBUG = false;
-
-  private static final int SECONDS_PER_MINUTE = 60;
-
-  public static final String HGT_EXT = ".hgt";
-  public static final String ZIP_EXT = ".zip";
-
-  // alter these values for different SRTM resolutions
-  public static final int HGT3_RES = 3; // resolution in arc seconds
-  public static final int HGT3_ROW_LENGTH = 1201; // number of elevation values per line
-  public static final int HGT_VOID = -32768; // magic number which indicates 'void data' in HGT file
-  public static final int HGT1_RES = 1;  // <<- The new SRTM is 1-ARCSEC
-  public static final int HGT1_ROW_LENGTH = 3601; //-- New file resolution is 3601x3601
-  /**
-   * The 'no elevation' data magic.
-   */
-  public static double NO_ELEVATION = Double.NaN;
-
-  private static String srtmFolder = "";
-
-  private static final Map<String, ShortBuffer> cache = new HashMap<>();
-
-  public HgtReader(String folder) {
-    srtmFolder = folder;
-  }
-
-  public static double getElevationFromHgt(double lat, double lon) {
-    try {
-      String file = getHgtFileName(lat, lon);
-      if (DEBUG) System.out.println("SRTM buffer " + file + " for " + lat + " " + lon);
-
-      // given area in cache?
-      if (!cache.containsKey(file)) {
-
-        // fill initial cache value. If no file is found, then
-        // we use it as a marker to indicate 'file has been searched
-        // but is not there'
-        cache.put(file, null);
-        // Try all resource directories
-        //for (String location : Main.pref.getAllPossiblePreferenceDirs())
-        {
-          String fullPath = new File(srtmFolder, file + HGT_EXT).getPath();
-          File f = new File(fullPath);
-          if (f.exists()) {
-            // found something: read HGT file...
-            ShortBuffer data = readHgtFile(fullPath);
-            // ... and store result in cache
-            cache.put(file, data);
-            //break;
-          } else {
-            fullPath = new File(srtmFolder, file + ZIP_EXT).getPath();
-            f = new File(fullPath);
-            if (f.exists()) {
-              ZipInputStream zis = new ZipInputStream(new BufferedInputStream(new FileInputStream(f)));
-              try {
-                for (; ; ) {
-                  ZipEntry ze = zis.getNextEntry();
-                  if (ze == null) break;
-                  if (ze.getName().toLowerCase().endsWith(HGT_EXT)) {
-                    // System.out.println("read zip " + ze.getName());
-                    ShortBuffer data = readHgtStream(zis);
-                    // ... and store result in cache
-                    cache.put(file, data);
-                    break;
-                  }
-                  zis.closeEntry();
-                }
-              } finally {
-                zis.close();
-              }
-            }
-          }
-        }
-      }
-
-      // read elevation value
-      return readElevation(lat, lon);
-    } catch (FileNotFoundException e) {
-      System.err.println("SRTM Get elevation from HGT " + lat + ", " + lon + " failed: => " + e.getMessage());
-      // no problem... file not there
-      return NO_ELEVATION;
-    } catch (Exception ioe) {
-      // oops...
-      ioe.printStackTrace(System.err);
-      // fallback
-      return NO_ELEVATION;
-    }
-  }
-
-  @SuppressWarnings("resource")
-  private static ShortBuffer readHgtFile(String file) throws Exception {
-    if (file == null) throw new Exception("no srmt file " + file);
-
-    FileChannel fc = null;
-    ShortBuffer sb = null;
-    try {
-      // Eclipse complains here about resource leak on 'fc' - even with 'finally' clause???
-      fc = new FileInputStream(file).getChannel();
-      // choose the right endianness
-
-      ByteBuffer bb = ByteBuffer.allocateDirect((int) fc.size());
-      while (bb.remaining() > 0) fc.read(bb);
-
-      bb.flip();
-      //sb = bb.order(ByteOrder.LITTLE_ENDIAN).asShortBuffer();
-      sb = bb.order(ByteOrder.BIG_ENDIAN).asShortBuffer();
-    } finally {
-      if (fc != null) fc.close();
-    }
-
-    return sb;
-  }
-
-  // @SuppressWarnings("resource")
-  private static ShortBuffer readHgtStream(InputStream zis) throws Exception {
-    if (zis == null) throw new Exception("no srmt stream ");
-
-    ShortBuffer sb = null;
-    try {
-      // choose the right endianness
-
-      byte[] bytes = zis.readAllBytes();
-      ByteBuffer bb = ByteBuffer.allocate(bytes.length);
-      bb.put(bytes, 0, bytes.length);
-      //while (bb.remaining() > 0) zis.read(bb, 0, size);
-
-      //ByteBuffer bb = ByteBuffer.allocate(zis.available());
-      //Channels.newChannel(zis).read(bb);
-      bb.flip();
-      //sb = bb.order(ByteOrder.LITTLE_ENDIAN).asShortBuffer();
-      sb = bb.order(ByteOrder.BIG_ENDIAN).asShortBuffer();
-    } finally {
-
-    }
-
-    return sb;
-  }
-
-  /**
-   * Reads the elevation value for the given coordinate.
-   * <p>
-   * See also <a href="http://gis.stackexchange.com/questions/43743/how-to-extract-elevation-from-hgt-file">stackexchange.com</a>
-   *
-   * @param lat, lon the coordinate to get the elevation data for
-   * @return the elevation value or <code>Double.NaN</code>, if no value is present
-   */
-  public static double readElevation(double lat, double lon) {
-    String tag = getHgtFileName(lat, lon);
-
-    ShortBuffer sb = cache.get(tag);
-
-    if (sb == null) {
-      return NO_ELEVATION;
-    }
-
-    if (DEBUG) System.out.println("SRTM buffer size " + sb.capacity() + " limit " + sb.limit());
-    try {
-      int rowLength = HGT3_ROW_LENGTH;
-      int resolution = HGT3_RES;
-      if (sb.capacity() > (HGT3_ROW_LENGTH * HGT3_ROW_LENGTH)) {
-        rowLength = HGT1_ROW_LENGTH;
-        resolution = HGT1_RES;
-      }
-      // see http://gis.stackexchange.com/questions/43743/how-to-extract-elevation-from-hgt-file
-      double fLat = frac(lat) * SECONDS_PER_MINUTE;
-      double fLon = frac(lon) * SECONDS_PER_MINUTE;
-
-      // compute offset within HGT file
-      int row = (int) Math.round((fLat) * SECONDS_PER_MINUTE / resolution);
-      int col = (int) Math.round((fLon) * SECONDS_PER_MINUTE / resolution);
-      if (lon < 0) col = rowLength - col - 1;
-      if (lat > 0) row = rowLength - row - 1;
-
-
-      //row = rowLength - row;
-      int cell = (rowLength * (row)) + col;
-      //int cell = ((rowLength * (latitude)) + longitude);
-
-      if (DEBUG)
-        System.out.println("Read SRTM elevation data from row/col/cell " + row + "," + col + ", " + cell + ", " + sb.limit());
-
-      // valid position in buffer?
-      if (cell < sb.limit()) {
-        short ele = sb.get(cell);
-        // check for data voids
-        if (ele == HGT_VOID) {
-          return NO_ELEVATION;
-        } else {
-          return ele;
-        }
-      } else {
-        return NO_ELEVATION;
-      }
-    } catch (Exception e) {
-      System.err.println("error at " + lon + " " + lat + " ");
-      e.printStackTrace();
-    }
-    return NO_ELEVATION;
-  }
-
-  /**
-   * Gets the associated HGT file name for the given way point. Usually the
-   * format is <tt>[N|S]nn[W|E]mmm.hgt</tt> where <i>nn</i> is the integral latitude
-   * without decimals and <i>mmm</i> is the longitude.
-   *
-   * @param llat,llon the coordinate to get the filename for
-   * @return the file name of the HGT file
-   */
-  public static String getHgtFileName(double llat, double llon) {
-    int lat = (int) llat;
-    int lon = (int) llon;
-
-    String latPref = "N";
-    if (lat < 0) {
-      latPref = "S";
-      lat = -lat + 1;
-    }
-    String lonPref = "E";
-    if (lon < 0) {
-      lonPref = "W";
-      lon = -lon + 1;
-    }
-
-    return String.format("%s%02d%s%03d", latPref, lat, lonPref, lon);
-  }
-
-  public static double frac(double d) {
-    long iPart;
-    double fPart;
-
-    // Get user input
-    iPart = (long) d;
-    fPart = d - iPart;
-    return Math.abs(fPart);
-  }
-
-  public static void clear() {
-    if (cache != null) {
-      cache.clear();
-    }
-  }
-}