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20030710: access to UPC NEXRAD Level III composite images

>From: Doug Nebert <address@hidden>
>Organization: FGDC
>Keywords: 200307101817.h6AIHcLd004395 LDM IDD FNEXRAD

Hi Doug,

>I see that NOAA has weather services syndicated to UNIDATA members
>and was wondering if any of them are preparing, and make available,
>a public full-res 1km, 4km, or 6km National Radar Composite from
>the NEXRAD sources as a GIF, PNG, or JPEG file on the Web.

We, the Unidata Program Center (UPC)/UCAR, are creating both 1 km and 6
km national composites of the NEXRAD Level III base reflectivity
products.  These products are generated every 10-15 minutes (10 minutes
for the 1 km product and 13-15 for the 6 km one).

The format of the 1 km image is a PNG-compressed image that looks
like:

              +-----------------------------+
              |                             |
              |   uncompressed header       |
              |                             |
              +-----------------------------+
              |                             |
              |                             |
              |       PNG compressed        |
              |           image             |
              |                             |
              |                             |
              |                             |
              |                             |
              +-----------------------------+

If one strips off the uncompresed header, the image portion of the
product can be viewed in any application that supports PNG.

The 6 km image is in McIDAS AREA format.

Examples of these products can be seen at:

http://my.unidata.ucar.edu/content/data/radar.html#composite

We deliver these images in near real time to Unidata sites
participating in our Internet Data Distribution (IDD).  For the most
part, these sites are universities in WMO Region IV.  We also try to
make it clear to our sites that there are a number of assumptions that
have gone into creating the composites, and that they are not intended
to be used operationally.  I can provide more information on this if
you are interested.

>My interest
>is in re-processing it, filtering out the map information

Our products do not have maps burned into them.  The are data files
that can be used in the analysis and display packages we distribute
and support, GEMPAK, IDV, and McIDAS.

>and creating
>a map service that would overlay the weather data on other map data
>from other servers using open protocols. Thus someone could choose 
>the reference information ontop/underneath from a variety of sources.

This sounds interesting and potentially very useful.

>The service would not be a commercial one

This is good to hear since Unidata is not funded to support commercial
activities.

>- it is more of a hobby project than a full-up research project,

Is this project part of the National Spatial Data Infrastructure, or
is it something that you want to do outside of the FGDC?

>but would be glad to share the map viewer and tools with the community.

Excellent, we are always looking for contributions back to our
educational and research community.

>How do you suggest I
>begin in seeking access to original or reprocessed data feeds?

The best way to get you the products is for you to setup and run an IDD
node at your place of business.  We would then feed you the images in
near real time, and you could experiment with them at your leisure.

Are you interested in getting a real time feed of the images?  If yes,
please read through our web pages that present the LDM and IDD to see
if you have the necessary equipment and network connection to support
an IDD node:

LDM
http://my.unidata.ucar.edu/content/software/ldm/index.html

IDD
http://my.unidata.ucar.edu/content/software/idd/index.html

If you have any questions concerning the LDM, IDD or Unidata in general,
please don't hesitate to ask.

>Doug.
>-- 
>Douglas D. Nebert
>Geospatial Data Clearinghouse Coordinator 
>FGDC/GSDI Secretariat  Phone: +1 703 648 4151  Fax: +1 703 648-5755

Cheers,

Tom Yoksas