Version 10, May 2010

[GpsPrune.git] / tim / prune / function / srtm / gen / GenerateTileLookup.java

diff --git a/tim/prune/function/srtm/gen/GenerateTileLookup.java b/tim/prune/function/srtm/gen/GenerateTileLookup.java
new file mode 100644 (file)
index 0000000..d797b13
--- /dev/null
+++ b/tim/prune/function/srtm/gen/GenerateTileLookup.java
@@ -0,0 +1,70 @@
+package tim.prune.function.srtm.gen;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+
+/**
+ * Class used to generate a lookup file to find the URLs of SRTM tiles.
+ * The tiles are split into directories for each continent, so we need some way
+ * of going from coordinates to directories.
+ * This class reads the directory listings from the files tiles1.txt, tiles2.txt etc
+ * and combines the result into a binary array
+ */
+public class GenerateTileLookup
+{
+
+       /**
+        * Main method for generating the array
+        * @param args ignored
+        */
+       public static void main(String[] args)
+       {
+               System.out.println("Generate tile lookup");
+               byte[] lookup = new byte[360 * 120]; // +/- 180 degrees longitude, +/- 60 degrees latitude
+               for (int f=1; f<= 6; f++)
+               {
+                       try
+                       {
+                               BufferedReader r = new BufferedReader(new FileReader(new File("tim/prune/function/srtm/gen/tiles" + f + ".txt")));
+                               String line = r.readLine();
+                               System.out.println("Read continent: '" + line + "'");
+                               while ((line = r.readLine()) != null) {
+                                       if (line.length() == 7)
+                                       {
+                                               boolean north = (line.charAt(0) == 'N');
+                                               int lat = Integer.parseInt(line.substring(1, 3));
+                                               if (!north) {lat = -lat;}
+                                               boolean east = (line.charAt(3) == 'E');
+                                               int lon = Integer.parseInt(line.substring(4));
+                                               if (!east) {lon = -lon;}
+                                               // Store in lookup
+                                               int arrindex = (lat+59)*360 + (lon+180);
+                                               lookup[arrindex] = (byte) f;
+                                       }
+                               }
+                       }
+                       catch (Exception e) {
+                               e.printStackTrace();
+                       }
+               }
+               // Now f should be populated
+               StringBuilder b = new StringBuilder();
+               for (int l=-180; l<180; l++) {
+                       int i = 59 * 360 + (l+180);
+                       b.append("" + lookup[i]);
+               }
+               System.out.println("equator: " + b.toString());
+
+               // Write bytes to file
+               try {
+                       FileOutputStream out = new FileOutputStream(new File("srtmtiles.dat"));
+                       out.write(lookup);
+                       out.close();
+               }
+               catch (Exception e) {
+                       e.printStackTrace();
+               }
+       }
+}