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[Fwd: Re: 20010711: Netcdf Java problem]



-------- Original Message --------
Subject: Re: 20010711: Netcdf Java problem
Date: Wed, 11 Jul 2001 10:30:59 -0600
From: Russ Rew <address@hidden>
Organization: UCAR Unidata Program
To: "Michael P Duff" <address@hidden>
CC: address@hidden, address@hidden

>To: address@hidden
>From: "Michael P Duff" <address@hidden>
>Subject: Netcdf Java problem
>Organization: UCAR/Unidata
>Keywords: 200107111340.f6BDeO122826

Hi Mike,

> Hi.  I am having a problem with the NetCDF Java version 2.  I am reading
> data from an existing NetCDF file using the read() function to place the
> data into an Array. The data is stored as a double in the Netcdf file. I 
> then use the IndexIterator to step through the Array.  I get a compile
> error.  I am using the code I found in the API for the Interface
> IndexIterator, the "Replace array with its square" example.  The program
> works if I just print the values instead of put them into a variable.  I
> have below my code, my compile error and the "Replace array with its
> square" example.  I would appreciate any help you can give me.
>
> Thank you,
>
> Mike
> ------------------------------------------------------------------------------------------------------------------------------ 
> // My code that gets a compile error
> import ucar.ma2.*;
> import ucar.nc2.*;
> import java.io.*;
> import java.util.*;
>
> public class ncproblem {
>
>      public static void main(String[] args) {
>           try {
>                NetcdfFile nc = new NetcdfFile(args[0]);
>                System.out.println(nc);
>                Variable heightVar = nc.findVariable("height");
>                System.out.println(heightVar);
>                int[] origin = new int[4];
>                origin[0] = 45000;
>                int[] shape = new int[4];
>                shape[0] = 50;
>                for (int i = 1; i<4; i+=1){
>                     origin[i] = 1;
>                     shape[i] = 1;
>                }
>                Array hgtVals = heightVar.read(origin,shape);
>                IndexIterator iter = hgtVals.getIndexIterator();
>                while(iter.hasNext()) {
>                     for(int i=0; i<50; i+=1) {
>                          Double val = iter.getDoubleNext();
>                          System.out.println(val + ",");
>                     }
>                }
>           }catch (java.io.IOException e) {
>                e.printStackTrace();
>           }
>      }
> }
> ------------------------------------------------------------------------------------------------------------------------------ 
> The compile error is:
> incompatible types
> found      :  double
> required:  java.lang.Double
>                               Double val = iter.getDoubleNext();
>                                                              ^
> 1 error
> ------------------------------------------------------------------------------------------------------------------------------ 

Since IndexIterator.getDoubleNext() returns double rather than Double,
you need to change this statement to:

   double val = iter.getDoubleNext();

After that, you'll get another compile error because the read() method
can generate an InvalidRangeException, which is not a java.io.IOException:
ncproblem.java:23: unreported exception ucar.ma2.InvalidRangeException; must be caught or declared to be thrown 
                Array hgtVals = heightVar.read(origin,shape);
                                         ^
One (crude) way to handle this would be to change your catch statement to:

          }catch (Exception e) {

--Russ