Radar Files, Questions...

[Robert Edmonds]

Hi all, so I've been doing some personal programming and have been trying to figure out where and how to get radar data. I assume software like gr level 3 gets data from http://www.nws.noaa.gov/tg/rpccds.html, however when I download some of the files through the ftp server, I can't figure out how to unarchive/decode/convert/etc these files. I have gotten rather lost trying to figure out what I need installed or what the best way to convert these things. Anybody around here know?

 

[John Wetter]

You can get lots of stuff including radar here: http://hurricane.ncdc.noaa.gov/pls/plhas/has.dsselect

The level2 stuff is gzip'ed and the L3 stuff is in a zip and then a file for each product for each time. You'll need to run the ncdctorv3 utility to view in GR3. Instructions for all of the above are in the owners forum.

Otherwise, if you're writing your own decoder, you'll have to refer to the NOAA documentation.

 

[Robert Edmonds]

Thanks for the response. I'm not trying to view the data in GRlevel3. I have been doing some unrelated programming in MATLAB and thought of some ideas that might be fun to play with in relation to radar. The goal is currently to figure out how to get data into the form of (Theta,Distance,Reflectivity/Velocity) for the various base reflectivity tilts/scans, and just a simple ASCII file would work. This would allow me to do some fun stuff, later on in MATLAB.

 

[Robert Edmonds]

You'll need to run the ncdctorv3 utility to view in GR3. Instructions for all of the above are in the owners forum.

Otherwise, if you're writing your own decoder, you'll have to refer to the NOAA documentation.

Looking back at some past files, I've played with ncdctorv3. However, I still don't know how to read these files except with grlevel3. When you say refer to the noaa documentation which documents would that be? There's plenty which describes the naming convention, but I've gotten lost trying to figure out how to decode these things. Thanks for any help!

 

[Skip Talbot]

Robert,

Here's an open source Java tool produced by NOAA that has level 3 and 2 viewing options. You could probably pick that apart and port it to whatever langauge you are using:
http://www.ncdc.noaa.gov/oa/wct/source.php

 

[Jeff Snyder]

Hi Robert,

I've been using L2 data in Matlab... Over the past few years, I've been working on a Matlab-based GUI to view radar data (in netCDF format). The entire program suite is actually designed for attenuation correction and hydrometeor classification of polarimetric weather radar data (primarily mobile radars, but it works the same for land-based radars), but you can certainly just use the "radar viewer" part of it. The newer versions of Matlab can deal with netCDF data natively, while older versions (which I designed in) need a netCDF toolbox to work correctly. If I were you, I'd persue radar data viewing in netCDF. You can keep building Matlab GUIs to make them more useable by adding keyboard shortcuts, etc... For example, you can zoom in/out and pan around using the keyboard, recenter based on mouse click, etc.

There are several ways to get the data into NetCDF format... I've been using "xltrsii", which is a part of soloii, to convert the 88D Level2 data to netCDF. The NOAA Weather and Climate Toolkit program can export to netCDF, but I'm not sure of the particular format that it uses (i.e. variable names, dimension names, etc).

 

[Sarah Glenn]

I've used that NOAA Java tool a lot as well to convert my radar data into shapefiles for use with ArcGIS. There are several different options for exporting data - I hope it helps!

 

[Robert Edmonds]

Success! Thank you everyone... With the batch convert and an m-file that converts nc files(since I have a older version of matlab) should do everything I need.