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[netCDFJava #XGJ-464529]: PointCollection

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  • Subject: [netCDFJava #XGJ-464529]: PointCollection
  • Date: Sat, 17 Jan 2009 21:08:20 -0700
> Full Name: Ann Marie Ascough
> Email Address: address@hidden
> Organization: USGS
> Package Version: 4.0
> Operating System: XP 64-bit
> Hardware:
> Description of problem:    I need to find a way to extract a block of data
from a Netcdf file. I have been using Java in Matlab to read the Netcdf files
but I have to find a way to efficiently grab a block of data from a file.
> I have a function that searches the file to find if a certain bounding box of
data is contained within the file, I am using the ProjectionRect class to do
that and it works great. Now I want to have that same function return the
actual data inside the bounding box. The getData method of Interface
PointCollection seems to be exactly what I am looking for but when I try to
initiate one of the classes that implements that method I generally get an
InstantiationException. I want to extract a group of data at one time because
these files are so large it takes over twenty minutes to search and extract
data point by point.
> Is there a better way to accomplish what I need?
> Thanks for your help.
> Ann Marie
>


Hi Ann Marie:

theres not really a magic bullet to efficiently extract point data. you are
limited to the array-oriented API thats documented in the NetcdfFile javadoc
(http://www.unidata.ucar.edu/software/netcdf-java/v2.2.22/javadoc/index.html).
Even if the system can open the file as a PointCollection, it will be using
those methods underneath.

netcdf is not an indexed file system, you may need to use a relational
database. if you want to send me a typical file, and what you are trying to do,
i can see if theres any obvious solutions.


Ticket Details
===================
Ticket ID: XGJ-464529
Department: Support netCDF Java
Priority: High
Status: Closed