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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++)
{
BufferedReader r = null;
try
{
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();
}
finally {
if (r != null)
{
try {
r.close();
} catch (Exception e) {}
}
}
}
// 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();
}
}
}
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