Ken Pavelle wrote:
John,
I'm having two problems upgrading my applet to the new jar file.
(Same results for ncCore-2.0.06 and 2.0.09). First, I get the
following runtime exception at the line where I set up my IndexIterator:
Exception in thread "AWT-EventQueue-2"
java.lang.IncompatibleClassChangeError
at RFCPanel.paintComponent(RFCPanel.java:691)
Any thoughts? Does this imply I don't have my array defined
properly? Has something changed with ucar.ma2.Array,
ucar.ma2.IndexIterator, ucar.nc2.NetcdfFile or ucar.nc2.Variable?
Note, the same code works when I use netcdf.jar version 2.1beta.
there were some changes in 2.2.09. It sounds like you should recompile
all your code against the new library. You may see some minor API changes.
Second, my main goal in upgrading to 2.2 is to be able to read .nc.gz
files. My original idea was to open the file with a GZIPInputStream,
read the data into a byte[] array, and then use
NetcdfFile.openInMemory. Looking through the javadoc for 2.2, I get
the impression that NetcdfFile.open takes the .gz extension into
account, meaning I don't have to go through the GZIPInputStream to
buffer to OpenInMemory. Is my impression correct?
NetcdfFile.open will look for compressed files like gz, decompress them
onto disk, and then open the decompressed file. SInce you are trying to
do everything in memory, it looks like you will need to keep doing that
yourself.
One final question. Any idea when you'll be ready to launch a beta
version of 2.2? I'm hearing concerns about putting code into
production that is based on alpha versions.
A valid concern. Its because of the the minor API tweaks that we are
still calling it alpha. The tweak was needed to improve performance to
an acceptable level for a certain special case. Otherwise the code is
getting pretty good testing, and there are several production packages
using it, including the IDV. Typically whatever changes made are minor,
and a recompile will discover and quickly fix them.
By the end of the month we'll probably go to beta, although there may be
some sections of the library that will remain alpha code, maybe the
"higher level" data types and the UI.
Thanks for your patience.
Thanks (again) for your time and help. Regards,
Ken Pavelle
John Caron wrote:
Ken Pavelle wrote:
John,
Can you help point me in the right direction? We have only one
novice Java programmer here, and I'm not even sure how big my
project is.
We have a Java applet that reads netCDF files and interactively
displays the data ( http://www.srh.noaa.gov/abrfc/precip/zoom.php
). I want to save user bandwith by reading gzipped netcdf files
instead. I can read the zipped file using java.util.zip, but the
netCDF Java library only reads from netCDF files, not from a memory
buffer.
How hard will it be for a decent Java programmer to extend the
netCDF java library (specifically NetcdfFile?) to read from buffer
instead of file?
Thank you for your time. (....even moreso if you have the time to
reply!)
Regards,
Ken Pavelle
NOAA, National Weather Service
Hi Ken:
unzip the file into a byte array, then call
NetcdfFile.openInMemory(String location, byte[] data)
then it should work as usual
make sure you have the latest version (2.2.06)
