RE: automatically detecting if a file contains a region of interest

2009-08-25T13:37:11Z

Edel, what exactly do you want to export and in which format? Find attached the Java code ProductDownloader.java which you can use as template (remove *.txt extension before compiling it). The template code downloads the file from a given URL and writes it to some directory. Then it checks if it intersects the ROI given by lon1, lon2, lat1, lat2. If so, it extracts something (not specified yet), otherwise deletes the downloaded data file.

1
2          URL url = new URL(args[0]);
3          File dir = new File(args[1]);
4          double lon1 = Double.parseDouble(args[2]);
5          double lon2 = Double.parseDouble(args[3]);
6          double lat1 = Double.parseDouble(args[4]);
7          double lat2 = Double.parseDouble(args[5]);
8          Rectangle2D roi = new Rectangle2D.Double(lon1, lat1, lon2 - lon1, lat2 - lat1);
9          File dataFile = downloadFile(url, dir);
10          Product product = ProductIO.readProduct(dataFile, null);
11          if (intersectsROI(product, roi)) {
12             extractData(product, roi);
13          } else {
14             dataFile.delete();
15          }

with

1
2 private static boolean intersectsROI(Product product, Rectangle2D roi) {
3       final GeneralPath[] boundaries = ProductUtils.createGeoBoundaryPaths(product);
4       // If product scene crosses the anti-meridian the can be two boundaries.
5       for (GeneralPath boundary : boundaries) {
6          if (boundary.intersects(roi)) { // can also use use path.contains(roi)
7             return true;
8          }
9       }
10       return false;
11 }

and

1
2 private static File downloadFile(URL url, File dir) throws IOException {
3       System.out.println("Downloading " + url + "...");
4       InputStream inputStream = new BufferedInputStream(url.openStream());
5       File outputFile = new File(dir, new File(url.getFile()).getName());
6       try {
7          final OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(outputFile));
8          try {
9             while (true) {
10                   int b = inputStream.read();
11                   if (b == -1) {
12                      break;
13                   }
14                   outputStream.write(b);
15             }
16             System.out.println("File written to " + outputFile);
17          } finally {
18             outputStream.close();
19          }
20       } finally {
21          inputStream.close();
22       }
23       return outputFile;
24 }

automatically detecting if a file contains a region of interest

2009-08-25T10:30:50Z

I just had a question regarding manipulating the MERIS data with Beam -
I am looking to write code that will download a data file, check if it contains a region of interest (e.g. by by specifying the latitude and longitude) and if so extract the data for that region of interest, if it doesn't contain that region, then just disregard the file.
Is it possible to write something automated like this relatively easy?