Community Newsletter
Winter 1994

Table of Contents

It's Like Mosaic to Your Ears (and Eyes!)

by Sally Bates, Information Manager at the Unidata Program Center

"I have the world's largest collection of seashells; I keep them scattered on beaches all over the world." --Steven Wright, comedian

Many academic institutions are beginning to use what promises to be a revolutionary new technology for publishing and accessing information over the Internet. The program, called Mosaic, makes it possible to access hypermedia documents on a multitude of servers springing up around the world. From an X Windows UNIX workstation, a Macintosh, or Windows PC, Mosaic enables you to read documents containing formatted text, sound, pictures, movies, and pointers to other documents on other servers anywhere in the world. Information on Gopher and FTP servers is also accessible via Mosaic.

What's Mosaic?

The brainchild of the National Center for Supercomputing Applications (NCSA), Mosaic was developed as an interface to the World Wide Web (see below). However, it is more than a simple client for a single type of server--you can use Mosaic to find and retrieve information not only from the mushrooming population of World Wide Web (WWW or just "Web," for short) servers, but also from Gopher, FTP, and Wide Area Information Servers (WAIS). You can even use Mosaic to run some useful Internet tools, such as archie and whois.

But Mosaic's reputation is based on it's use as a Web client. Indeed, because of Mosaic, accessing Web information is currently the fastest growing segment of Internet use.

The Power of the Web

The World Wide Web is a type of information server developed by CERN (the Conseil Europeen pour la Recherche Nucleaire, the European laboratory for particle physics). WWW allows you to create hypertext documents that link files of many different types. Essentially, Web documents are multimedia presentations, the pieces of which may reside anywhere on the Internet and may consist of any type of digital information: text, sound, video, or static images. You can, for example, create a Web document that links a text file on your local server, some static images on another machine, and a movie with sound at a third site on the other side of the world.

What makes the linking possible is Web's use of "Uniform Resource Locators" (URLs). URLs extend the familiar UNIX filenames and pathnames to include machine names (such as www.unidata.ucar.edu) and server type (such as Gopher, FTP, or Web). With URLs, "not only can you point to a file in a directory, but that file and that directory can exist on any machine on the network, can be served via any of several different methods, and might not even be something as simple as a file: URLs can also point to queries, documents stored deep within databases, the results of a finger or archie command, or whatever" (from "A Beginner's Guide to URLs," NCSA Mosaic's on-line help document).

You can easily configure how links will appear in the documents you view. You traverse links with single mouse clicks and can save the URLs of your favorite servers or documents in a clickable "hotlist." Most people find that creating their own hypertexted documents is also easily done--Mosaic interprets a limited set of HTML (Hypertext Markup Language) tags that are quick to learn and apply to any plain text document. In addition, Web users have written many freely available translation scripts that convert existing documents in numerous formats into HTML-tagged Web documents.

The ability to link different types of files is already transforming how we exchange information, but I believe it will also fundamentally alter some of our basic notions about that information. If you link existing documents together, does that constitute a new "document"? Are you then an "author"? Could a "library" be merely a vast set of links to documents scattered all over the world like the seashells in the quote that opened this article? We will need to closely reexamine the way in which we define fundamental units of communication and the characteristics which we assign to them.

Accessing the Web

Using the Web effectively depends on having good connections to the Internet. And the more powerful your platform, the faster the Mosaic client will display your information. Mosaic was designed for UNIX systems running X Windows, but it has now been ported to Macintosh, PC, and PC-clone platforms (see "Where to Get It" for information on where to find the applications mentioned in this article). The Macintosh client requires a machine running the System 7 operating system or later and the PC or clone client is for 486 machines running Windows (operation on a 386 machine is possible, but slow).

There are also some text-based browsing tools available for accessing the Web; we recommend using one of these if you have a slow connection to the Internet or if you want to dial in to a server from home. At the UPC we use Lynx (developed by Lou Montulli at the University of Kansas) when we need a text-only browser. The Lynx program must be running on the computer supplying your terminal access.

Creating "Eyes" on the Globe

At the UPC, Mosaic has offered the opportunity to greatly enhance what we formerly called the Unidata Campus Weather Display system. Rather than simply sending a set of weather files (text and graphics) from your department to terminals around campus, Mosaic and the Web allow you to organize and present an enormous range of information for your users to access interactively. These tools also allow you to point to other sites in "hyperspace," linking your server to others around the globe to meet the particular needs and interests of your users.

Inspired by this paradigm and by the astonishing wealth of information appearing on university servers, the Unidata staff have begun creating what we call an Integrated Earth Information Server (IEIS, pronounced "eyes"). Our prototype IEIS illustrates how a site can combine the Unidata Internet Data Distribution software (that is, the LDM) with the Web-server software to create a varied collection of files and links for use in a range of educational activities.

Our IEIS prototype contains a variety of earth-related information. The server's "home page" (the Mosaic term for the entry point to the server) explains the IEIS concept and includes example links to interesting servers containing earth information such as weather and ocean data. More links will be added as new repositories are discovered. You can click here now to visit the Unidata IEIS server.

The Unidata IEIS server is also a mirror site for the University of Michigan's Blue Skies data files. Indeed, we see mirroring popular servers as a second, desperately needed function of IEIS servers. Mirroring (where files are copied automatically at regular intervals) will benefit the Unidata community by spreading around the demand that often overwhelms popular servers.

The Unidata IEIS is running on a workstation that was donated to the Unidata Program by Sun Microsystems. The machine is located at NSF headquarters in Virginia and maintained by the UPC; it will be used for community-related activities. It currently holds the IEIS Web server and a Gopher server, which although it contains a link toUnidata's Gopher server in Boulder, will be devoted primarily to American Meteorological Society information.

We hope our IEIS prototype will inspire you to create your own local IEIS servers that reflect the interests and information needs of your users. We are eager to see our sites expand and improve on our example.

The UPC Web Server

We are also running a Web server on a Unidata computer in Boulder. We have information about our applications, various projects, and our staff; we have also included a link to our Gopher server. The Unidata Web server includes some first efforts at on-line documentation: the NetCDF Users Guide and the LDM Site Managers Guide. We will eventually convert all of the user documents that we produce within the UPC into Web-compatible form.

We would appreciate any suggestions for additions or improvements. In the meantime, we urge you to obtain the Mosaic client software and try it out; you'll love it--guaranteed!

Where to Get It

Mosaic is freely available from NCSA via anonymous FTP at:

ftp.ncsa.uiuc.edu

XMosaic is located in the directory Mosaic/Mosaic-binaries/, MacMosaic in Mac/Mosaic/, and WinMosaic in PC/Mosaic/.

External viewer applications are also available in directories called either Helpers/ (for Mac or PC clients) or Mosaic-viewers/ for UNIX clients.

UNIX Web-server software is available at the same FTP address in the
Web/ncsa-httpd/httpdversion#/ directory.

NCSA's FTP server is often overloaded, however, so NCSA has established a mirror site at:

sunsite.unc.edu

Various clients are located in the directory pub/packages/infosystems/WWW/clients/Mosaic/Mosaic-NCSA

A Web server called MacHTTP is available for Macintosh computers. Once you have the MacMosaic client you can get the server software by first clicking on the Other Useful Applications link on the MacMosaic homepage and then clicking on another link on that page.

A PC Web server can be obtained in a similar fashion with the PC client.

Lynx is freely available via anonymous FTP from:

ftp2.cc.ukans.edu

in the pub/lynx/ directory.

New for Spring: GEMPAK 5.2

by Peggy Bruehl, User Support Programmer at the Unidata Program Center

The big news for the GEMPAK community these days is the coming release of GEMPAK version 5.2 from the National Meteorological Center (NMC). This new version of GEMPAK will be ready for Unidata distribution late this spring. Currently, Unidata and a few test sites in the community have "beta test" versions of GEMPAK 5.2, and we are testing, experimenting with, and porting the software. In its final form, GEMPAK 5.2 will offer new functionality as well as two separate graphical user interface (GUI)-driven programs, NSAT and NTRANS.

Highlights of the GEMPAK 5.2 release will include the ability to display and overlay satellite images and the ability to create animations within a GEMPAK X Window. GEMPAK will access satellite data in the McIDAS AREA format, and display it via the GEMPAK device drivers (X Window, PostScript, etc.). The imagery will be navigated, and maps and data may be overlaid with any GEMPAK program. (It should be noted that the NMC implementation of this capacity is based on work originally done at the Naval Postgraduate School.) Animation within a GEMPAK X Window will allow the user to specify, generate, and then loop through a series of graphics.

In addition, GEMPAK 5.2 will contain three new programs, GDPLOT, GDTHGT, and NAGRIB. GDPLOT combines all the functions of the existing gridded data programs into a single program. The user can plot multiple fields (scalar and vector) from a single run of the program, thus eliminating long, complicated procedures for generating contour plots overlaid with vector plots. GDPLOT will also allow sequential generation of graphics at multiple times--again from a single run of the program--which will be particularly useful with the animation feature. GDTHGT is a program originally developed by the Scientific Services Division of the NWS Western Region for creating time-height cross sections as a function of time from gridded data. NAGRIB is a GEMPAK program for decoding GRIB messages into GEMPAK grid files.

GEMPAK 5.2 will include the requisite bug fixes and a long list of minor enhancements as well. These include: forecast valid times in graphic titles; new diagnostic functions; labeled minima and maxima on contour plots (H/L); mouse input for determining areas and cross-section lines; more control over reference arrows; vector scaling factors; changes to the system libraries for better handling of message queues; global defaults files; new device drivers; color bars for any color-filled contours; staggered wind barbs; and better color tables. Note that many of these enhancements either come from or have been suggested by Unidata and the GEMPAK community.

In addition to the standard GEMPAK distribution, this release will include two new programs: NTRANS and NSAT. NTRANS is a meta-file animator and viewer for graphics files generated with GEMPAK. It has an easy-to-use GUI which makes it ideal for casual users to use for viewing GEMPAK graphics. It is being heavily used by the Operations Division at NMC to examine and compare model output. Click here to see the NTRANS user interface and an example display.

The Unidata distribution of NTRANS will include a set of sample scripts for generating graphics products typical of those used by operational meteorologists at NMC, the National Hurricane Center, and other sites. These scripts will serve as examples of how you can use NTRANS and GEMPAK as a real-time demonstration system in the classroom, in the laboratory, or for map briefings.

NTRANS requires Motif, so it is not directly accessible to sites running SunOS and OpenWindows. Unidata will provide a binary executable of NTRANS, generated from Motif and X11R5. However, this executable will not work reliably on Suns running versions of OpenWindows older than version 3.3, which have basic incompatibilities with X11R5 applications. Sun sites wishing to run NTRANS should run an X11R5 server, either OpenWindows 3.3 (available with Solaris 2.3) or the X11R5 distribution available from MIT.

NSAT, similar to NTRANS, is a GUI-driven program for viewing satellite imagery. It was developed to provide the operational meteorologists at NMC with a modern tool for looping and viewing satellite data. The Unidata community may find NSAT to be most useful as a demo system, particularly in light of the satellite overlay and animation capabilities included in GEMPAK 5.2. NSAT was developed in the same environment as NTRANS and the same X11R5 requirements hold.

Once GEMPAK 5.2 is in its final form and delivered to Unidata, we will provide tools that allow installation on the Unidata-supported platforms in a uniform and integrated way. We will also work closely with NMC in generating and contributing to a GEMPAK 5.2 users manual. NMC is also planning users manuals for NTRANS and NSAT.

After the distribution of GEMPAK 5.2, NMC plans to work with COMET (the Cooperative Program for Operational Meteorology, Education and Training) and Unidata in designing a GUI for GEMPAK programs. We plan to implement the GUI in three phases. The first phase is to generate a "forecaster" GUI which provides easy access to standard meteorological charts and quantities with a predetermined set of parameters that determine the look and feel of the GEMPAK graphics. For example, temperature contours might always be in Celsius and be drawn in red. You will have the freedom to select the areas and fields (from a list) to display and overlay. The next phase will introduce more flexibility into the interface and require more knowledge of and skill in running GEMPAK. The third and final phase will combine the GUIs into a comprehensive interface that allows the generation of both "forecaster-type" standard plots and also fully specified graphics, which require more extensive knowledge of GEMPAK. In all phases, the text-based interface will remain as part of the package, thus maintaining access to GEMPAK from non-graphics terminals.

All announcements about the GEMPAK 5.2 release will be made via gembud--the "GEMPAK buddies" mailing list. For more information about GEMPAK, or to subscribe to the gembud mailing list, contact support@unidata.ucar.edu.

The NTRANS User Interface

The NTRANS user interface. The small window in the upper right is the "Select Model" window, which allows you to easily choose the type of data to display. Below the "Select Model" window is the "Group Selection" window, which allows you to choose the fields to be displayed. NTRANS is one of several useful new features debuting in GEMPAK 5.2. Clicking on the image above will display the same image at its actual size.

Unidata McIDAS Continues to Evolve

by Tom Yoksas, User Support Programmer at the Unidata Program Center

The next release of Unidata McIDAS is tentatively scheduled for late May or early June of this year. Both McIDAS-X version 1.9 and McIDAS-OS2 version 5.9 contain some useful new features, and still more improvements are under development for future releases.

A GUI for McIDAS-X...

Perhaps the most exciting addition in Unidata McIDAS-X 1.90 will be an intuitive, easy-to-use, mouse-driven, graphical user interface (GUI).

We know that Unidata's users are eager for a consistent GUI for the various application packages that we distribute, but there is no consensus on what the critical elements of such a GUI would be. It is apparent that no single GUI will satisfy all users, so we decided to pursue a "toolkit" approach that would allow individuals to customize an example GUI for their own institutional and personal needs. The search criteria led us to explore the freely available Tcl/Tk package (see sidebar).

We have used Tcl/Tk to produce a sample GUI that will debut in McIDAS-X 1.9. One of the key features of this GUI is that your choices are displayed in plain text throughout the interface. This allows novice users to interact with McIDAS without knowing arcane details of how McIDAS functions. At the same time, expert users will have full access to all levels of McIDAS, including the traditional command-line interface. All users will be able to lessen or increase their exposure to McIDAS intricacies through widgets (user interface objects) that are configurable on the fly and savable on a per-user basis so that they can always use an environment that is familar and comfortable.

Click here to see an example configuration of the McIDAS-X GUI. The University of Wisconsin's Space Science and Engineering Center (SSEC) is also investigating Tcl/Tk, as well as other object-oriented user-interface techniques; this exploratory work could eventually lead to new features such as a drag-and-drop capability.

...and more!

Another useful addition to McIDAS-X is support for pseudo-independent graphics and imagery. Users will be able to turn on or off either the graphics overlaid on a satellite image or the image itself. This capability makes it easier to see the different information contained in the image and graphic portions of a display.

There will be a new command--REFRESH--in the new release of McIDAS-X (and McIDAS-OS2 as well); it replaces the Unidata- supported SEQ and ALOOP commands. REFRESH can be used to load new loops of imagery or update existing loops when new images are received in the broadcast. Sites using Unidata McIDAS with Integrated Earth Information Servers (IEIS, the new name for the University Campus Weather Display system) will find that the REFRESH command greatly simplifies the task of producing graphics and imagery automatically.

Lastly, in version 1.9, SSEC McIDAS-X supports Hewlett Packard HP 9000 workstations. Even though HP platforms are not directly supported by Unidata, we will insure that nothing we add to McIDAS-X will prevent it from working on HPs.

McIDAS OS/2 continues to improve as well

As in McIDAS-X, McIDAS-OS2 5.9 supports the new REFRESH command (see the discussion earlier in this article of the advantages this command offers).

To facilitate command-mode use, the command stack (the list of previously executed commands) has been increased from 20 to 100.

In order to lessen screen burn produced when VGA monitors are left on for extended periods, McIDAS-OS2 now contains screen-blanking capabilities. You can choose the interval of inactivity that will cause the McIDAS session to blank the video display. The screen-blanking approach taken does not affect displays in non-McIDAS sessions or in the Presentation Manager.

Beyond McIDAS-OS2 5.9

SSEC has been working on converting McIDAS-OS2 to a full 32-bit application. The resulting executables have demonstrated remarkable improvements in speed , especially in the area of mapping on satellite imagery, where 32-bit routines are typically twice as fast as their 16-bit counterparts. In order to lessen the financial impact on sites actively doing McIDAS development work, SSEC is using the freely-available Fortran-to-C conversion utility, f2c, and GNU C compiler, GCC. Fortran routines are first converted to C and then compiled with GCC.

Since we expect to see a full 32-bit version of McIDAS-OS2 available by the fall of 1994, you should begin to migrate from OS/2 1.3--which does not support 32-bit applications--to OS/2 2.1. In conjunction with the new develop- ment efforts and in keeping with SSEC support policies, Unidata is now announcing that support of OS/2 1.3 will be sunsetted on January 1, 1995 (SSEC's sunset of OS/2 1.3 was January 1, 1994).

Ongoing development activities

We previously reported on preliminary SSEC investigations aimed at reformulating McIDAS into a client-server architecture, dubbed the Distributed Data Environment (DDE). Since initial beta-site DDE tests have been successful, SSEC is pushing ahead with full development.

SSEC is reevaluating support of a Presentation Manager based McIDAS-OS2 in addition to the full-screen implementation that is now supported.

Investigation of SVGA support on OS/2 workstations is being undertaken on a low-priority basis by both SSEC and Colorado State University-Cooperative Institute for Research in the Atmosphere; this work could potentially lead to higher resolution image and graphic displays with full 8-bit gray level support for satellite imagery.

There are several investigations into porting McIDAS-X to PC-based versions of UNIX (e.g. Linux, BSDI, and UHC); movement to a UNIX environment would allow PC-only sites to run the LDM and receive data via the Internet Data Distribution system being developed by Unidata.

The MUG and SSEC

So how can Unidata users influence the development of SSEC McIDAS? Many Unidata McIDAS users may not be aware that SSEC supports McIDAS implementations (OS/2, UNIX, and MVS) through the McIDAS User's Group (MUG). Unidata represents its member universities' interests by participating as a single member of the MUG. In addition to voicing your concerns through the MUG, Unidata typically adds additional functionality to "core" McIDAS when areas of deficiency are identified.

Through the MUG, we can voice your desires for changes in SSEC-supported McIDAS. The charter of the MUG has been expanded to encourage development of new software both above and below the application's programming interface. If you have not expressed your opinions about needed developments in McIDAS, contact Unidata User Support with your recommendations before the next release, tentatively scheduled for late May or early June.

The SSEC McIDAS support staff has been reorganized into several development teams. Unidata users will be most interested in the development of new applications and the revision of existing ones to make McIDAS even more useful. Changes in the coming release are in part a result of this development work.

New data products available

Last year we announced that three products produced by WetNet principle investigators from the Defense Meteorological Satellite Program/Special Sensor Microwave Imager (DMSP SSM/I) data would be available in the Unidata/Wisconsin channel. The availability of these products was delayed for a variety of reasons that were beyond the control of Unidata. We have recently been informed by a WetNet representative that the full complement of products produced by WetNet will be made available to the Unidata community. At this time it is unclear, due to budget constraints, whether these products will be made available in the Unidata/Wisconsin data channel or by Internet means (either the IDD or FTP). We anticipate that these products will be available by the end April or early May.

In the next month or so, SSEC will begin making US climate data available to the Unidata community in the form of McIDAS MD files. Initially, the entire 1993 climate database of weekly averages will be made available to users by Internet FTP. Later, the current 1994 climate database will be distributed via the broadcast multiple times in order to insure that sites have correctly received it. Thereafter, each week the averages for the week just ending will be sent in the broadcast. In order for users to be able to correctly receive the data, we will distribute a new McIDAS-OS2 decoder module (IMPORT) via the broadcast. The equivalent for McIDAS-X users will be available by FTP from Unidata. Since our policy is to give users at least one month lead time before adding new products to the data stream, the broadcast of the climate data will not begin before the middle of May.

Perhaps the most exciting news is the upcoming availability via IDD of the National Lightning Detection Network (NLDN) data that will be provided by SUNY Albany and GeoMet Data Services. This data product is discussed in more detail on page 14 of this newsletter. NLDN data decoders that convert from the native, binary NLDN data format to Unidata netCDF and McIDAS MD forms are already available. Contact Unidata User Support for further information.

In mid-December of last year, SSEC announced the availability by FTP of global infrared satellite imagery that is a combination of GOES, METEOSAT, and GMS imagery. These McIDAS AREA files, which are updated every three hours, are available by anonymous FTP in the pub/incoming directory on ssec.wisc.edu as AREA0998.

For those of you using Gopher or Mosaic, there are numerous examples of McIDAS, GEMPAK, and WXP-produced displays available at various locations.

Tcl/Tk-based McIDAS-X GUI

Image of McIDAS-X menu widgets

One possible configuration for a Tcl/Tk-based McIDAS-X GUI. This example shows a small subset of the user-configurable widgets. Just above the scrollbar at the bottom of the main menu window, the McIDAS command line is displayed. The small window in the corner is a scrollable pull-down menu.

More About Tcl/Tk

Tcl/Tk allows users to easily create X Window-based GUIs with simple UNIX shell scripts. Interface code is simple ASCII text, which lets you use your favorite text editor to modify GUI examples provided by Unidata, SSEC, and others. Since Tcl/Tk syntax is relatively easy to learn and since the code used in building the interface is interpreted, we believe even the least experienced McIDAS user will be able to quickly produce functional interfaces with a minimum of effort.

Unidata experiments with McIDAS-X indicate that Tcl/Tk contains essentially all of the major elements needed to produce fully functional GUIs. An especially attractive feature of Tcl/Tk is its widespread use by a large group of developers that routinely exchange ideas by Internet NetNews (in the comp.lang.tcl newsgroup).

Sites interested in getting a head start on using Tcl/Tk are encouraged to FTP the package, print out the documentation, and experiment with the various demos that come with the package. Tcl/Tk is freely available by anonymous FTP from sprite.berkeley.edu.

Tcl/Tk was developed by John Ousterhout of UC Berkeley.

Profiler Network Update

by Linda Miller, External Programs Coordinator at the Unidata Program Center

The saga continues...

The President's budget, released on February 7th, does not include funding for NOAA's Wind Profiler Demonstration Network managed and operated by Forecast System Laboratory (FSL) in Boulder, Colorado. The network is scheduled to shut down by September 30, 1994, unless Congress restores the funding required to continue operation.

Last summer there was a frequency allocation issue arising from a concern of continued use of the 404.37-MHz frequency. Interdepartmental Radio Advisory Committee (IRAC) threatened to suspend operation of the network. Many letters were sent by the university community to support the network for use in their education and research activities. After lengthy deliberation, IRAC tentatively made the decision to grant an extension of the renewal of the 404.37-MHz license for continued operation of the network.

But so does development...

Recently, a group from the University Navstar Consortium (a UCAR Office of Programs organization), in conjunction with North Carolina State University, the FSL Profiler Program Office, and NOAA's Environmental Technology Laboratory experimented on five profilers in Colorado, Kansas, and Oklahoma by placing Global Positioning System (GPS) receivers on the profilers to take precipitable water measurements. The 30-minute measurements agree very well with the radiometers and with the 12-hour balloon soundings. The GPS systems, unlike the radiometers, are largely insensitive to rain or condensation on the antennas.

Radio Acoustic Sounding Systems (RASS) add-ons have been installed on five profilers to measure air temperature profiles. They have been taking accurate measurements consistently at 3 km and sometimes to 5 or 6 km above the ground.

The experiments being performed with the wind profilers have been leading toward a single site observation of wind, atmospheric temperature, and precipitable water vapor every hour.

Mail Call! More Lists for the Mill

K-12 mailing list

Since a number of Unidata sites have strong K-12 outreach efforts already in progress, the Users Committee recommended that the UPC establish a K-12 email list.

The list is designed for discussion about outreach to the K-12 community by the Unidata community in atmospheric and related sciences. While K-12 outreach is the main focus of this list, discussion will probably encompass local community colleges, vocational schools, etc., as universities become more involved with community outreach. We envision discussions covering such topics as contacts (education departments at institutions of higher learning, school districts, schools, teachers, state and federal education departments), how to set up weather and earth science resources for use by K-12 instructors, integrating weather and earth science into K-12 curricula, and how to foster ties between Unidata sites and local communities.

In order to foster the ties across institutions, the email list will be open to anyone interested: Unidata site members, local teachers, and other K-12 representatives suggested by Unidata site members. The ieis@unidata.ucar.edu email list will remain for discussion of campus weather displays, Web and Gopher servers, implementations on campus, and so on. The ieis list should focus more on work in higher education, although we expect to see overlap.

The new list is aptly named:

k12@unidata.ucar.edu

To add/delete/change addresses on the list, please send email to:

k12-request@unidata.ucar.edu

An archive of the list is available on the Unidata Gopher under:

>> Unidata Comunity Information
>> Unidata-related Educational Outreach Information
>> Email Archive of k12@unidata.ucar.edu

Data request email list

For general requests about all forms of data, we have created a new email list:

needdata@unidata.ucar.edu

If we can get people to subcribe to and use this list, it will deflect a lot of requests that currently go to the community mailing list. Please send subscription requests to needdata-request@unidata.ucar.edu.

IDD Contracts Awarded

by David Fulker, Unidata Program Center Director

A competition has just been completed by which two well known firms, Alden and WSI, were selected as the awardees for contracts to inject real-time weather data products into the Internet Data Distribution (IDD) system for use by Unidata universities. Alden will handle Family of Services (FOS) data, and WSI will inject NEXRAD Information Dissemination System (NIDS) products, both employing Unidata software.

Unidata universities have worked with Alden to acquire FOS data since 1985, but most universities heretofore have not had access to NEXRAD data, so important new education and research opportunities seem likely to arise as the new agreements are implemented. Furthermore, as FOS data formerly were conveyed via satellite transmission, use of Internet as the distribution medium represents a major architectural change in the Unidata system. Both WSI and Alden have been enthusiastic in committing themselves to collaborate with Unidata toward effective use of the Internet in this capacity. At the same time, both offer alternative means of data delivery for colleges and universities where sufficiently capacious or reliable Internet connections are unavailable.

Within two months Alden and WSI will begin participating in our IDD test effort, installing computers with Unidata (LDM) software, relaying data to other test participants, and keeping records that permit us to measure the reliability and speed of end-to-end data delivery. This testing period likely will include a number of software and configuration changes as problems are diagnosed and possible solutions are tried. If the tests are successful within the time frame we have planned, full-scale deployment of the IDD system (beyond the initial test sites) will begin by year's end and require a year or so for completion.

In other words, our target for (nearly) universal IDD system use is the fall semester of the 95-96 academic year, by which time any university may choose to acquire FOS or NIDS via Internet. (A corollary is that budgets should anticipate continued reliance on satellite reception of FOS through calendar year 1995, and longer if Internet connectivity is questionable!) Those institutions requiring reliable access to NIDS prior to the 95-96 academic year should contact WSI to discuss alternate means for receiving the needed data.

Although Unidata's agreements with Alden and WSI both envision Internet as the principal means of data delivery, the two differ greatly in respect to costs and usage permissions. Under the new Alden contract, universities will pay nothing to acquire FOS data via the Internet; in contrast, Internet access to NIDS can be gained only by those Unidata universities which have paid WSI for a specific subscription, the costs for which will be limited by the Unidata-WSI contract. Eventually, the effect of this will be to reduce the aggregate university expenditures for FOS data by some $220,000 per year, but needs for NIDS may prevent Unidata universities from actually lowering their data acquisition budgets. There also are differences in how FOS and NIDS may be employed by Unidata universities: the Alden contract allows significant flexibility, such as for redistributing FOS data to K-12 schools, while the WSI agreement limits use to the campus and imposes other constraints which we believe are reasonable in the light of current National Weather Service policies on NIDS.

Further details on price ceilings, usage permission, and available services will be described in a special edition of the Unidata newsletter to be published soon.

Lightning Data Available via Internet

The State University of New York at Albany (SUNYA), through a cooperative agreement with Global Atmospherics, offers data from the National Lightning Detection Network (NLDN) to universities over the Internet. these data are available at no cost for education and research, under constraints established by Global Atmospherics and SUNYA and outlined below.

NLDN data emanates from SUNYA via the same LDM5 mechanisms employed for other types of information in our Internet Data Distribution (IDD) initiative.

Data delivery overview

SUNYA runs an LDM5 server that is the primary distribution point for NLDN data. Each individual flash detected by the NLDN is collected in a six-minute bin before being ingested into the SUNYA LDM server. The data consists of a binary packet containing the following fields for each lightning flash:

Field Example
date/time (msec) 09/22/93 10:22:33.334
latitude 47.33
longitude -87.116
polarity/signal strength -188.7
multiplicity 6
ellipse angle 174
semi-major axis 6.0
eccentricity 2.0
chi-square 1.0

When a lightning data packet is received by an LDM server, a decoder may be automatically invoked to convert the NLDN-native format to, for example, a Unidata netCDF file. Unidata and SUNYA have established an IDD feedtype, NLDN, for this data stream.

Software that allows McIDAS, GEMPAK, and WXP to use NLDN data is available from Unidata. Contact support@unidata.ucar.edu for further information on how Unidata software may be used to analyze and display lightning data.

How to access NLDN data

SUNYA controls LDM5 access to the NLDN data; universities interested in receiving the NLDN data should contact David Knight. These universities will be able to use the data for one month to determine the scope and usability of the data. After that time, a brief, one-page document (synopsis) of the planned use/publication must be submitted for Global Atmospherics approval. Submissions should be made to Dr. David Knight as above. Global Atmospherics policy prohibits redistribution of or financial gain from these data.

Data Archives--Volunteers Needed

The UPC has begun keeping a list of volunteer data-archive sites. The list can be viewed on the Unidata Gopher under the following headings:

>> Information about Unidata Software Packages and Projects >> Data Archive Sites (Community Volunteers)

The list contains sites and contacts who may be able to help out those who are missing data for whatever reason. These are not meant as real-time data sites, and access will be controlled by the sites. If you would like to volunteer your site to help the community, please contact support@unidata.ucar.edeu

Unidata Supported Platforms

Editor's Note: This file is maintained for archival purposes; the chart on this page may not show the platforms currently supported for running Unidata software.

This table shows the computers and operating systems currently supported for Unidata-distributed software. The specifications for UNIX platforms represent a fairly minimal, LDM-compatible system for data-ingest and file-server duties that also allows color-graphics display for user applications. The OS/2 configurations are only for sites running McIDAS-OS2. Any site budgeting for new equipment should bear in mind that there will be continuing expenses for the data-broadcast services and for hardware and software maintenance. As a rule of thumb, maintenance costs roughly ten percent of the purchase price per year per item. Much more elaborate systems can be purchased to support specific site requirements. You should consult the Unidata Program Center staff before any equipment purchase or upgrade.

* Some Unidata packages (netCDF and LDM4, for example) are actually supported on a wider range of platforms. See the specific package documentation for information on whether the software has been ported and tested on additional platforms.

Is Your Software Up-to-Date?

The chart below lists the currently distributed versions of Unidata supported software packages and their release dates. Forthcoming releases are also noted. You should check the version numbers of the applications on your system to see that they match those given below. If you have questions, contact Unidata at support@ucar.unidata.edu.

Please send comments to info@unidata.ucar.edu