@Test
/**
* Find min/max/average precipitation for a randomly-positioned but fixed-size region from a nc
* file output: filename,origin,size key: value:min, max, average
*
* @throws Exception
*/
public void testProcessingNASANexDataInNetCDF() throws Exception {
final int SIZE = 100;
File file = new File(this.getClass().getResource("/ncar.nc").getPath());
byte[] netcdfinbyte = FileUtils.readFileToByteArray(file);
// use any dummy filename for file in memory
NetcdfFile netCDFfile = NetcdfFile.openInMemory("inmemory.nc", netcdfinbyte);
Variable time = netCDFfile.findVariable("time");
ArrayDouble.D1 days = (ArrayDouble.D1) time.read();
Variable lat = netCDFfile.findVariable("lat");
if (lat == null) {
logger.error("Cannot find Variable latitude(lat)");
return;
}
ArrayFloat.D1 absolutelat = (ArrayFloat.D1) lat.read();
Variable lon = netCDFfile.findVariable("lon");
if (lon == null) {
logger.error("Cannot find Variable longitude(lon)");
return;
}
ArrayFloat.D1 absolutelon = (ArrayFloat.D1) lon.read();
Variable pres = netCDFfile.findVariable("pr");
if (pres == null) {
logger.error("Cannot find Variable precipitation(pr)");
return;
}
Random rand = new Random();
int orig_lat = rand.nextInt((int) lat.getSize());
orig_lat = Math.min(orig_lat, (int) (lat.getSize() - SIZE));
int orig_lon = rand.nextInt((int) lon.getSize());
orig_lon = Math.min(orig_lon, (int) (lon.getSize() - SIZE));
int[] origin = new int[] {0, orig_lat, orig_lon};
int[] size = new int[] {1, SIZE, SIZE};
ArrayFloat.D3 data3D = (ArrayFloat.D3) pres.read(origin, size);
double max = Double.NEGATIVE_INFINITY;
double min = Double.POSITIVE_INFINITY;
double sum = 0;
for (int j = 0; j < SIZE; j++) {
for (int k = 0; k < SIZE; k++) {
double current = data3D.get(0, j, k);
max = (current > max ? current : max);
min = (current < min ? current : min);
sum += current;
}
}
logger.info(
days
+ ","
+ absolutelat.get(orig_lat)
+ ","
+ absolutelon.get(orig_lon)
+ ","
+ SIZE
+ ":"
+ min
+ ","
+ max
+ ","
+ sum / (SIZE * SIZE));
}
