/*
* Copyright 1998-2009 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
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* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
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* software or in any product that includes this software. The names UCAR
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package ucar.nc2.iosp.misc;
import ucar.nc2.constants.CDM;
import ucar.nc2.iosp.*;
import ucar.nc2.NetcdfFile;
import ucar.nc2.Variable;
import ucar.nc2.Attribute;
import ucar.nc2.Dimension;
import ucar.nc2.util.CancelTask;
import ucar.nc2.util.IO;
import ucar.unidata.io.RandomAccessFile;
import ucar.ma2.*;
import java.io.IOException;
import java.io.File;
import java.util.StringTokenizer;
/**
* GTOPO 30 sec elevation data from USGS
* http://edc.usgs.gov/products/elevation/gtopo30/gtopo30.html
*
* @author caron
*/
public class GtopoIosp extends AbstractIOServiceProvider {
public boolean isValidFile(RandomAccessFile raf) throws IOException {
String location = raf.getLocation();
if (!location.endsWith(".DEM")) return false;
int pos = location.lastIndexOf('.');
String stub = location.substring(0, pos);
File hdrFile = new File(stub + ".HDR");
return hdrFile.exists();
}
public String getFileTypeId() {
return "GTOPO";
}
public String getFileTypeDescription() {
return "USGS GTOPO digital elevation model";
}
private int nlats = 6000;
private int nlons = 4800;
private float incr = .008333333333333333f;
private float startx, starty;
public void open(RandomAccessFile raf, NetcdfFile ncfile, CancelTask cancelTask) throws IOException {
super.open(raf, ncfile, cancelTask);
readHDR();
ncfile.addDimension(null, new Dimension("lat", nlats));
ncfile.addDimension(null, new Dimension("lon", nlons));
Variable elev = new Variable(ncfile, null, null, "elevation");
elev.setDataType(DataType.SHORT);
elev.setDimensions("lat lon");
elev.addAttribute(new Attribute(CDM.UNITS, "m"));
elev.addAttribute(new Attribute("units_desc", "meters above sea level"));
elev.addAttribute(new Attribute(CDM.LONG_NAME, "digital elevation in meters above mean sea level"));
elev.addAttribute(new Attribute(CDM.MISSING_VALUE, (short) -9999));
ncfile.addVariable(null, elev);
Variable lat = new Variable(ncfile, null, null, "lat");
lat.setDataType(DataType.FLOAT);
lat.setDimensions("lat");
lat.addAttribute(new Attribute(CDM.UNITS, CDM.LAT_UNITS));
ncfile.addVariable(null, lat);
Array data = Array.makeArray(DataType.FLOAT, nlats, starty, -incr);
lat.setCachedData(data, false);
Variable lon = new Variable(ncfile, null, null, "lon");
lon.setDataType(DataType.FLOAT);
lon.setDimensions("lon");
lon.addAttribute(new Attribute(CDM.UNITS, CDM.LON_UNITS));
ncfile.addVariable(null, lon);
Array lonData = Array.makeArray(DataType.FLOAT, nlons, startx, incr);
lon.setCachedData(lonData, false);
ncfile.addAttribute(null, new Attribute(CDM.CONVENTIONS, "CF-1.0"));
ncfile.addAttribute(null, new Attribute("History", "Direct read by Netcdf-Java CDM library"));
ncfile.addAttribute(null, new Attribute("Source", "http://eros.usgs.gov/products/elevation/gtopo30.html"));
ncfile.finish();
}
private void readHDR() throws IOException {
String location = raf.getLocation();
int pos = location.lastIndexOf('.');
String HDRname = location.substring(0, pos) + ".HDR";
String HDRcontents = IO.readFile(HDRname);
StringTokenizer stoke = new StringTokenizer(HDRcontents);
while (stoke.hasMoreTokens()) {
String key = stoke.nextToken();
if (key.equals("ULXMAP"))
startx = Float.parseFloat(stoke.nextToken());
else if (key.equals("ULYMAP"))
starty = Float.parseFloat(stoke.nextToken());
else
stoke.nextToken();
}
}
public Array readData(Variable v2, Section wantSection) throws IOException, InvalidRangeException {
// raf.seek(0);
raf.order(RandomAccessFile.BIG_ENDIAN);
int size = (int) wantSection.computeSize();
short[] arr = new short[size];
LayoutRegular indexer = new LayoutRegular(0, v2.getElementSize(), v2.getShape(), wantSection);
while (indexer.hasNext()) {
Layout.Chunk chunk = indexer.next();
raf.seek(chunk.getSrcPos());
raf.readShort(arr, (int) chunk.getDestElem(), chunk.getNelems()); // copy into primitive array
}
return Array.factory(v2.getDataType().getPrimitiveClassType(), wantSection.getShape(), arr);
}
}