Hi All,
Really cool!
Dan Kelley, Jon Meek, Rich Signell, and William Weibel have been suggesting
some fantastic ideas! On their inspiration I decided to try a test hook up: how
to make Ferret into a Web application to analyze and visualize NetCDF files
directly from the Web. It works like a charm. The (very short) nitty gritty of
setting it up is below. Also some test sites with NetCDF data.
This illustrates some of the power of NetCDF as a file standard. It also
illustrates some of its limitations - especially regarding the lack of
standardization ... an opportunity to keep up the chatter on the standards
efforts:
http://www.unidata.ucar.edu/packages/netcdf/conventions.html
- steve
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Here are some test sites where I had instant success with this technique:
http://ferret.wrc.noaa.gov/data
("test.nc" is deliberately small for testing)
try
yes? shade sst[t=15-jan]
http://ferret.wrc.noaa.gov/fbin/climate_server
has a number of research-quality climate data sets with
fast access to data subsets - select any 1,2,3 or 4
dimensional region and ask for a NetCDF file.
http://www.cdc.noaa.gov
The Climate Diagnostics Lab has an extensive NetCDF archive.
Sample navigation: select "Data Archives Overview"
then "a collection of metadata" then "coads1" then
"sea_level_pressure" then "slp.ltm.nc" (ltm refers to "Long
Term Mean" so this is a small file). There's lots of data
and it's well documented but most of the files are pretty
large for this type of browsing.
http://rainbow.ldgo.columbia.edu/datacatalog.html
Lamont-Doherty Earth Observatory of Columbia University is
another big NetCDF data supplier. For a test navigation try
Data Library Tour->Finding a dataset->Datasets by Source->
Datasets by Source->CLIMAP->Last Glacial Maximum->Temperature->
Data Files->netCDF format
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Here's how I to set up (hacked) to run Ferret as a Web helper:
1) in my home directory I created file netcdf_via_ferret with these
lines:
#! /bin/csh
source /home/r3/tmap/bin/ferret_paths
echo use \"$argv[1]\" >! $HOME/.ferret
echo show data >> $HOME/.ferret
/usr/bin/X11/xterm -e $FER_DIR/bin/ferret
Note: i) these paths are for OSF ... slight diffs on other systems
ii) make sure to "chmod +x netcdf_via_ferret"
iii) thie script over-writes your .ferret file
2) in ~/.mailcap add the line
application/x-netcdf; /home/rogue/hankin/tmp/dump_that_file %s
3) in ~/.mime.types add the line
application/x-netcdf nc cdf
You'll probably have to start up a fresh copy of your browser (Netscape) so it
rereads the .mailcap information.
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Of course, all this assumes that Ferret is already installed on your system. If
it is not you can download it from
http://www.pmel.noaa.gov/ferret/home.html
or ftp://abyss.pmel.noaa.gov/pub/
--
| NOAA/PMEL | ph. (206) 526-6080
Steve Hankin | 7600 Sand Point Way NE | FAX (206) 526-6744
| Seattle, WA 98115-0070 | hankin@xxxxxxxxxxxxx
