Re: Help with ncML for aggregation

address@hidden wrote:

> Hi John,
>
> I have had a bit of a break from the netcdf project I had been working on, but 
> now I am back on the trail :)
>
> My geoTiff writer needs a bit of work, but it uses JAI to create a tiff:
>
> JAI.create("filestore", bufferedImage, filepath, "TIFF", null);
>
> and then a write a text "world file" to match the tiff image.
>
> The only problem I came across was that the numbers in the world file needed to 
> be in the following format:
>
> DecimalFormat format=new DecimalFormat(".00000000000000");
>
> The numbers in the world file (in order) needed to be:
>
> xscale
> brotation
> crotation
> yscale
> xOriginCentre
> yOriginCentre
>
> In any case, when I tidy up the code into a neat little API, I will forward it 
> on to you.
great, id like to see it.

> ---
>
> I have a question or two about NcML.
>
> I am using NcML to aggregate netcdf files that hold data for a particular 
> month. Below is a copy of my test NcML file.
>
> <netcdf xmlns="http://www.ucar.edu/schemas/netcdf"; 
> 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; 
> 	xsi:schemaLocation="http://www.unidata.ucar.edu/schemas/netcdf.xsd 
> http://www.unidata.ucar.edu/schemas/netcdfDataset.xsd";>
>
>  <dimension name="lat" length="2100" /> 
>  <dimension name="lon" length="1600" />
>  <dimension name="time" length="61"/> 
>
>  <variable name="SST_AVE" type="float" shape="time lat lon"/>
>
>  <netcdf uri="file://\\moon\risdev\ferret\data\mar.nc">
>    <dimension name="time" length="31" />
>  </netcdf>
>
>  <netcdf uri="file://\\moon\risdev\ferret\data\apr.nc">
>    <dimension name="time" length="30" />
>  </netcdf>
>
> </netcdf>
>
>
> I could get the java NetCDF API to read it and aggregate, using the following 
> code segment:
>
> <code>
>
> NetcdfFile ncfile = NetcdfDataset.factory("C:\\sst_ncml.xml",null);
>                       
> NetcdfDataset nDataset = ucar.nc2.dataset.conv.Convention.factory(ncfile);
>            
> // find the coordinate system used in this netcdf file
> List systems=nDataset.getCoordinateSystems();
> Iterator iSys=systems.iterator();
> while (iSys.hasNext()) {
>  CoordinateSystem sys=(CoordinateSystem)iSys.next();
>  GridCoordSys grid=new GridCoordSys(sys);
>                
>  Date fromDate=aims.util.StringUtilities.convert2Date("11/03/2003");
>  Date thruDate=aims.util.StringUtilities.convert2Date("26/04/2003");
>                
>  int minT=grid.findTimeCoordElement(fromDate);
>  int maxT=grid.findTimeCoordElement(thruDate);
>                
>  System.out.println("date indexs:" + minT + " " + maxT);
> }
>
> </code>
>
> However, there are zero coordinates systems, so the code within the while loop 
> never executes. I assume I must define a coordinate system within the NcML 
> file, which I have done and the XML is shown in the attachment. The code within 
> the while loop still does not execute. Can you tell me what am I doing wrong?
>
> Thanks for your time,
>
> Mark
>
>  
the dataset aggregation is very "alpha" quality, so it may be a bug.

would it be easy to send me the 2 underlying netcdf files so i can 
reproduce the problem?

PS: i am gone for 10 days on vacation, so i wont get back to you again 
for a bit.

thanks,

John