Re: netCDF files

• To: "Scheller, Robert M." <rmscheller@xxxxxxxxxxxxxxxxx>
• Subject: Re: netCDF files
• From: John Caron <caron@xxxxxxxxxxxxxxxx>
• Date: Thu, 17 May 2001 14:54:20 -0600

Scheller, Robert M. wrote:

Dear John Caron:

I am a grad student at UW-Madison and I have been attempting
to work with a suite of VEMAP climate data files in the
netCDF format.  Although the User's Manual for NetCDF Java
has been helpful, I am utterly stuck.  It appears fairly
simple to create the NetcdFile class.  However, I want only
a very small subsection of the data.  It appears that ma2.Index
would provide this function but I haven't been able to
make the logical leap from creating the NetcdFile class to
creating a MultiArray that I can index on.  Specifically, it
isn't clear to me how to use the MultiArray read() functions

on a netcdfile.

Also, what is the constructor for the Range

class?  Thanks very much for any information, advise or

references you could provide.

there's also online javadoc there, you can look up the Range class


Sincerely,

Rob Scheller

Robert M. Scheller
Dept. Forest Ecology & Management
University of Wisconsin - Madison
1630 Linden Dr., Madison, WI 53706
w: 608.265.6321

Visit my webpage! http://landscape.forest.wisc.edu/staff/rob/
Forest Landscape Ecology Lab  http://landscape.forest.wisc.edu

package test.nc2;

import ucar.ma2.*;
import ucar.nc2.*;

import java.io.*;

public class ExampleRead  {

  public static void main(String [] args) {
    new ExampleRead();
  }

  public ExampleRead() {

    try {

      System.out.println( "ncfile "+ ncfile);

      Variable temp = ncfile.findVariable("temperature");
      System.out.println( "temperature "+ temp);

      // read subset
      int[] origin = {1,3};// start at index [1,3]
      int[] shape = {2,2}; // 2x2 array

      Array As = temp.read( origin, shape);
      System.out.println( "physical subset");
      printArray( As);

      // read all the data and logically subset it
      Array A = temp.read();
      Range[] r = new Range[2];
      r[0] = new Range(1,2);
      r[1] = new Range(3,4);

      Array Ap = A.section( r); // logical subset
      System.out.println( "logical subset");
      printArray( Ap);


    } catch (InvalidRangeException e) {
      System.err.println("ERROR reading file "+e);
      return;
    } catch (IOException e) {
      System.err.println("ERROR reading file "+e);
      return;
    }

  }

  private void printArray( Array a) {
    IndexIterator iter = a.getIndexIterator();
    while (iter.hasNext())
      System.out.println( iter.getDoubleNext()+ ",");
  }
}