J-F de La Beaujardière
delabeau@iniki.gsfc.nasa.gov
P Keegstra
pkeegstr@leaf.gsfc.nasa.gov
H Mitchell
horace.mitchell@gsfc.nasa.gov
C O'Handley
ohandley@gilbert.gsfc.nasa.gov
S W Stemwedel
sstemwed@leaf.gsfc.nasa.gov
T Williams
twilliam@leaf.gsfc.nasa.gov
NASA Goddard Space Flight Center
We preview the newest version of the GLOBE Visualization system, to be released in time for Earth Day 1997 (22 April). Building upon the current version, we provide support for geographically distributed mirror sites, multiple languages with provisions for local customization, a choice of text or graphical display modes, and access via electronic mail for locations with limited network access. Additionally, the new version allows visualizations to be generated for arbitrary location, zoom level, and date. Our goal is to allow access by anybody to all of the data.
The GLOBE Program (http://www.globe.gov/) is a hands-on environmental science and education program that joins students, educators, and scientists from around the world in studying the global environment. Over 3,000 schools in 46 countries are participating in GLOBE. GLOBE students make a core set of environmental observations at or near their schools, report their data through the Internet to a GLOBE data processing facility, and study global images created from worldwide GLOBE school data. GLOBE is a U.S. Government program administered by NOAA, NASA, NSF and EPA.
NASA Goddard Space Flight Center's role is to produce and disseminate visualizations of GLOBE student data and of reference data. Version 1 of the GLOBE Visualization server (hereafter v.1) was inaugurated on Earth Day 1995 and has been described elsewhere (de La Beaujardière, Mitchell & Hasler 1995; de La Beaujardière et al. 1997). This paper discusses version 2 (v.2), which substantially enhances access to the data.
The core of version 2 is software that generates images and HTML. Using a choice of interface styles and native languages, as discussed below, users specify the location, magnification, date, and dataset to be visualized. The system creates the image on demand and sends it to the user along with annotation and with user interface controls to request a different image product. The visualizations are generated using Interactive Data Language (IDL), with CGI scripts and supporting software in Perl and C. In v.1, images were created in advance for a predefined set of locations and dates. V.2 improves access to the data by lifting those restrictions. Figure 1 shows a sample image generated by the v.2 system.
![[Image of student data]](fig1.gif) |
| Figure 1: Map produced with v.2 of the GLOBE visualization system showing GLOBE student maximum temperature measurements for 1 October 1996 in California. The square glyphs represent individual stations (schools); the colored region is an objective analysis of the station data using the Barnes interpolation algorithm (Koch, des Jardins, & Kocin 1983). |
The v.2 system supplements the geographic display of data with the ability to plot data as a function of time. Thus, users can compare different datasets from a given school or the same data for different schools. Figure 2 shows such a graph.
![[Plot of student data]](fig2.gif) |
| Figure 2: Time series plot showing GLOBE temperature measurements as a function of time for a particular school. The red and blue lines show minimum and maximum daily air temperature, respectively. |
The goal of the GLOBE Program is to support all of the United Nations official languages (Arabic, Chinese, English, French, Russian, Spanish). Character encoding issues are problematic, of course, and cannot be resolved by GLOBE alone. In v.1, we used language-independent pictographs instead of words. In v.2 we provide two options. The current v.1 pictorial interface has been retained as a simplified interface which is familiar to current users but offers fewer features. Figure 3 shows the graphical control panel.
![[Simplified interface]](fig3.gif) |
| Figure 3: Language-independent, icon-based control used in v.1 and retained as an option in v.2. The controls are displayed beneath a visualization like that in Figure 1. |
For the other language option in v.2, we established a framework within which any language can be inserted. All software which displays text strings visible to the user (e.g., menu titles, image annotation, etc.) reads those strings from language-specific configuration files. Translators need merely create files in their own language, using an existing language as a starting point, and add the new language to the list of those available. The footer of each web page includes links to all languages available on that server. The forms-based user interface, which is complementary to the simplified iconic interface but offers access to more features, can be displayed in multiple languages. Figure 4 shows the French version of the control panel.
![[Complete interface]](fig4.gif) |
| Figure 4: French-language version of the forms-based control panel. The controls are displayed beneath a visualization like that in Figure 1. |
Note that any language, whether recognized by the UN or not, can be handled by this system. Thus, local mirror sites (see below) can provide a version in their own native language, however obscure. The only requirement is that the necessary phrases be representable as a series of bytes. We currently have in-house expertise in English and French and are working with outside translators for other languages.
The default access method for GLOBE imagery is via a graphics-capable WWW client. Users navigate geographically by clicking on a map and select other parameters using HTML form elements. To accommodate text-to-speech converters and clients on low-bandwidth links, a text-only version is available in both v.1 and v.2; in text mode, users select an image using text-entry boxes and text-only menus and buttons. The system creates the image and presents a page that describes the resulting image, provides a hypertext anchor to retrieve it, and includes all controls necessary to select a different image. Once the more basic display modes are in place, we will add a Java applet option for clients which support it.
Note that we do not choose a default presentation based on the USER_AGENT field sent by the client. Instead, the page footer includes a link to all available display modes for that particular CGI script and the user makes the choice explicitly (and can bookmark it for later access). We may implement HTTP transparent content-negotiation mechanisms (Holtman & Mutz 1997) when they become established.
GLOBE does not wish to exclude any school on the basis of network connectivity. Some participants cannot access the World Wide Web but do have electronic mail capability. In v.1 we therefore introduced an email image server (images@globe3.gsfc.nasa.gov) which sends the user an order form, processes incoming order forms, and sends back a MIME-encoded GIF. This feature will be adapted to the on-demand image creation available in v.2. (Note that students can already submit data via email instead of the default web-based forms.)
Schools without any network connectivity whatsoever can submit data on paper via the postal services and receive hardcopy images by the same route. At present, one GLOBE country operates in this manner.
To facilitate access by international participants and minimize impact on the network, GLOBE visualizations are available from several sites. V.1 has sites on both the East and West coasts of the US and a site in Australia. Negotiations are underway for v.2 to be mirrored at sites in Europe and Asia, and other locations are encouraged. As mentioned earlier, local sites can provide language translations if desired. We envision the minimum requirements to be a Pentium-class machine running Unix and served by a dedicated link, and expect that GLOBE countries or regions will establish local servers to replicate our software and the raw data.
Version 2 of the GLOBE Visualization system focuses on providing access to all the GLOBE data by anybody regardless of native language or network bandwidth. In version 1, we provided a fixed set of images for the current week, we used pictographs in lieu of text for language-independence, and we provided an English text-only mode, email access, and three mirror sites. Version 2 will provide the ability to access arbitrary locations and dates, plots of data as a function of time as well as location, translation into an arbitrary number of languages, continued email access, and additional mirror sites.
de La Beaujardière, J-F, Cavallo, J., Hasler, A. F., Mitchell, H., O'Handley, C., Shiri, R., and White, R. 1997, Journal of Science, Education and Technology, 6, no. 1, 15: "The GLOBE Visualization Project: Using WWW in the Classroom."
de La Beaujardière, J.-F., Mitchell, H., & Hasler, A. F. 1995, 4th International World Wide Web Conference Poster Proceedings, p.28: "MultiView: A WWW-Based GUI for Navigating Multi-Dimensional Information Spaces."
Holtman, K. & Mutz, A. 1997, IETF HTTP Working Group Internet-Draft, ftp://ds.internic.net/internet-drafts/draft-ietf-http-negotiation-01.txt: "Transparent Content Negotiation in HTTP."
Koch, S.E., M.desJardins, and P.J. Kocin, 1983, J. Climate Appl. Met., 22, 1487-1503: "An interactive Barnes objective map analysis scheme for use with satellite and conventional data."