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Volume 46, Number 2March/April 1995

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Maps From the Sky

Written by Ian Meadows
Photographs courtesy of Institut Geographique National

In a darkened laboratory at France's National Geographic Institute (IGN) in Toulouse, we watched, fascinated, as the first scan of Gaza and the West Bank came up on the computer screens. The data, showing water resources in bright false color, had been unloaded a short satellite in orbit 830 kilometers (516 miles) up, tirelessly circling the globe once every 101 minutes.

This space survey had been commissioned by the European Economic Community as a contribution to Palestinian autonomy, and it underscored not only the enormous utility of satellite-gathered space imagery but also its vast potential for cooperative international monitoring of the extent of global resources, their social and economic applications, and the health of Mother Earth in general.

Gaza was by no means the first satellite-survey subject in the Middle East. In the past few years, SPOT Image, together with IGN International, the Institute's commercial arm, has been helping a number of Arab states monitor, inventory and thus rationalize the use of their resources. One important recent mission minutely surveyed the shrinking Nile Delta; another is helping Egypt find potentially habitable desert areas to relieve growing population pressure.

Earlier, there had been mapping projects in Saudi Arabia's Rub' al-Khali, the Empty Quarter in the south and west of the country, and a meticulous 3100-square-kilometer (1197-square-mile) mosaic of Riyadh, the kingdom's thriving capital city. The new jargon of such imaging enterprises, the sophisticated equipment they use, the huge volumes of data they produce, and the dazzling speed at which it's collected, corrected and processed into useful form, all emphasize how effective and powerful this "hands-across-the-sky" cooperation can be.

Toulouse, in southwestern France, where SPOT Image and IGN International have their operational headquarters, is aptly called the European space center. A number of major space and aviation organizations are grouped here, including the industry leader—and parent of both SPOT Image and IGN International—the National Center for Space Studies (CNES).

The first SPOT satellite was placed in orbit eight years ago by an Ariane rocket (See Aramco World, March-April 1985), the second was launched in 1992 and the third a few months ago, with two further launches scheduled before the end of the century. But IGN's association with Arab countries began much earlier, in the spring of 1976, when the Institute set up a training center in Amman and undertook an aerial—that is, non-satellite—scan of 200 Jordanian villages. Since then some 400 engineers have been trained in the Amman center, and it is clear that Jordan's recent data inputs will someday be placed back-to-back with the material from Gaza and the West Bank, as the parties concerned work out how the resources they must share will be divided.

During those early years, before the first SPOT satellite was launched, IGN was frequently commissioned to process data from other sources. In the late 70's, for example, IGN carried out a two-year geodesic survey in Libya using American Landsat data. That and other experience with mapping desert terrain helped the French institute win a contract from Saudi Arabia's Ministry of Petroleum and Mineral Resources to survey the Rub' al-Khali, and the 10-year project, using aircraft and terrestrial methodology, led in turn to the large-scale mapping of Riyadh, intended to support long-term urban and regional planning.

IGN International director Rene Thomas looks back to those days in Saudi Arabia and calls the decade that he devoted to the project well-spent. Some 300 IGN specialists and their Saudi counterparts worked on the trailblazing $10-million project in the Rub' al-Khali. Saudi technicians traveled frequently to France for specialist training in topography and other disciplines, many staying on to help analyze the data coming out of the Empty Quarter.

Thomas remembers vividly the highs and lows of those years: the team's astonishment when water bubbled to the surface as technicians sank a geodesic marker 30 meters into the shifting dunes, and the anxiety when a single-engine survey aircraft crash-landed in a blinding dust storm. "We covered thousands of square kilometers," he says, "getting to know this fabulous desert in a way few people ever do.

"'Empty' is a misnomer," he adds: "The Rub' al-Khali contains many hidden riches."

Thomas also points out that Saudi Arabia commissioned such other aerial and satellite surveys as a country-wide road system survey, and is thus particularly well placed to plan and support its domestic development and—by pooling information with neighboring states—cooperate in regional surveys as well.

In 1986, with the Rub' al-Khali project still underway, the assignment to map the Municipality of Riyadh came in. The multi-billion-dollar undertaking was a Saudi-French joint venture, and is still one of the largest and most sophisticated mapping projects ever undertaken. Run by the Saudi Ministry of Municipal Affairs, it took in 1800 square kilometers (695 square miles) of the metropolis itself and a further 1300 square kilometers (502 square miles) of contiguous area. The result was a complete, computerized urban-information system able to give planners a variety of visual "products" in black-and-white or color. Some were thematic—that is, designed for specific uses like highway planning, property demarcation, forest management, water management or agricultural planning; others were cartographic, such as photo-mosaics and digital, relief and conventional maps—all at scales ranging from 1:50,000 (about 1" to 4200') to 1:500 (1" to 42').

IGN International's work in Yemen was also an extensive project. With a population of 14 million, 70 percent of it under the age of 24 and 62 percent illiterate, the country stood only 160th in the United Nations's national wealth rankings—a bleak picture to which the discovery of oil brought the prospect of considerable change. IGN contracted to delineate 37 oil-concession zones for the government.

To do that, a SPOT satellite picked out 236 geodesic reference points—benchmarks—while technicians on the ground set up another 1814 markers and implanted 1869 gravimetric stations to measure the earth's gravitational pull. Thirty IGN technicians, mostly geometricians, plus five Yemeni colleagues and 15 other staff then went to work to match the "ground truth" with remote-sensing data. Their vehicles crisscrossed 3400 kilometers (2100 miles) of road and desert track—sometimes in quite unsettled parts of the country—while a base team set up sophisticated electronic theodolites and laid down six global positioning system receivers. "We knew there were risks, of course," says mission chief Gérard Cosquer, "but after all, isn't it better to lug your theodolite around exciting places than to let it sit unused somewhere in a storeroom in Toulouse?"

The outbreak of war ended a planned $5-million extension of IGN's survey into the south of Yemen, but IGN/SPOT Image has stayed very busy all over the Arabian Gulf and North Africa. Clients are often understandably shy about discussing the objectives of their projects or the use they plan to make of the data, but missions were successfully completed in Bahrain (complete cartographic coverage of the island) and Oman (one government commission, two from the private sector). During this same period, IGN also mapped the whole of southern Morocco using SPOT imagery at a 1:100,000 scale (1" to 1.6 miles), setting up a ground control center and a complete geographic information system (GIS).

In the late 80's, French specialists analyzed the Djibouti geological fault around the Horn of Africa, analyzing the movement of the African tectonic plates. Working with the World Bank, the French group also carried out cadastral (property-boundary) surveys in Tunisia and Algeria, and set up both a GIS to assist forestry and general agricultural management, and a full cadastral system for Tunisia.

IGN works closely with international bodies such as the World Bank, the Food and Agriculture Organization (FAO), the United Nations Development Project (UNDP) or the European Economic Community. Naturally there's competition with US and Russian satellite data providers, but IGN officials cite a very clear trend toward "joint goals" discussions that will lead to more efficient use of the various satellites' capabilities.

Nations that contribute to international aid and development organizations like the World Bank or UNDP—"especially the United States," notes René Thomas, "see their money commitment backed by crackingly effective, hard, satellite-gathered economic data in support of requests for loans or financial assistance. They know precisely where the money will be used most effectively, and they have easily retrievable and constantly updated real-time computer data at their disposal 365 days a year."

Among SPOT's numerous other non-classified assignments was an ethno-geographic survey of Nubian monuments in cooperation with the United Nations Educational, Scientific and Cultural Organization and the Center for Documentation and Study of Ancient Egypt. The project grew mightily while in progress, yielding a unique cartographic and topographic antiquities inventory not only of the mammoth statues but also of the royal necropolises in Thebes, and taking in even the countless rock faces bearing graffiti scratched by workmen in Pharaonic times!

Meticulously recording the past is a very real contribution to world heritage, but more pressing 21st-century tasks awaited the French technicians in Egypt, where soaring population figures and man-made factors such as the Aswan dam have created new problems.

"Cartography is something like insurance," says one senior IGN official. "You only realize how fantastically useful it is when you actually need it." This was true of Egypt when IGN, in late 1991, mobilized for the first phase of a $27-million job for the Egyptian Ministry of Agriculture and Land Reclamation. The ultimate objective was to help Cairo boost food self-sufficiency; the means were measuring and monitoring existing planted areas; determining how sowing and harvesting of main crops had changed; assessing urban encroachment on arable land; and analyzing the potential for bringing new land areas under cultivation.

Phase one of this undertaking, now completed, involved the monitoring of four million hectares of land (9.9 million acres) in 6240 "reference plots," produced 25 land-utilization maps (scale 1:100,000) and identified 10 main crops harvested twice yearly, along with a score of related parameters like Nile flow and flood movement.

In addition, Egyptian specialists underwent two years' training in France, where the project was financed, and now constitute a solid, well-trained nucleus of manpower that will be put to use in phase two. Running through 1995, that phase will identify potentially useable desert areas.

Parallel to these efforts is the Nile Delta project, where SPOT-gathered data show not only the significant shrinkage of the Delta over the past 20 years but also the intense demographic pressures that are building up. Both projects—once the data are correlated—serve the ultimate goal of relocating more than a million Egyptians to newly reclaimed desert areas.

Other North African nations with satellite data experience have been watching these developments closely, and none more so than Tunisia, which in December 1993 hosted an international space mapping symposium attended by delegates from 40 countries. The meeting defined goals for international cooperation, notably identification of national requirements in satellite-derived cartography; integration of satellite data into geographic information systems; and measurement of the economic impact of space-gathered imagery—some of which, delegates believe, is likely to overturn long-cherished concepts in land and water management.

One speaker at the symposium cited 78 remote sensing programs—worth $35 billion—that have been completed through 1993, with eight more missions under way and another 45 planned. Arab space specialists lauded France's generosity in transferring space imagery technology, including access to some 3500 kilometers (2175 miles) of new, processed data tape annually, 1300 yearly maps and an awesome 36 gigabytes of stored data.

The Tunis symposium, and planned Arab attendance at the Paris Eurospace summit meeting this year, show that the majority of Arab states are very much aware of the benefits of using space imagery to achieve the most efficient use of all their resources—human, natural and technological—and some are in very good positions to integrate their own data with their neighbors' to potentiate its value.

"In practical terms," says René Thomas, "we are watching a new environmental awareness take shape, with growing influence among decision-makers like the UNDP, the World Bank and FAO. The latter is pushing for a massive satellite resource inventory of sub-Saharan African states that are 'at risk' in terms of development—among them Sudan, once potentially the Arab world's largest food producer [See Aramco World, May-June 1978]. The European Community, with its eye on what it calls Euro-Mediterranean co-prosperity, favors a satellite-gathered inventory of the countries on the Mediterranean and the great rivers, among them seven Arab states."

Thomas continues, "Projects like those will heighten awareness. They could be the catalyst for an even bolder plan that I understand has backing in the US and Japan: to mobilize financial resources in support of a giga-project—a global anatomy of our planet, compiled from data gathered by satellites."

Journalist and author Ian Meadows, who has a longstanding interest in Middle East economic matters, lives in France's Languedoc.

How It Works

Three SPOT satellites now watch the earth. Each is in a circular, approximately north-south orbit 830 kilometers (516 miles) above the earth, and completes 14 orbits every 24 hours. Because the earth turns under the satellite, the ground track of each orbit is 2823 kilometers (1754 miles) west of the previous orbit: If the satellite passes over Charlotte, North Carolina on one orbit, it will pass over Flagstaff, Arizona on the next, or if it passes over Ankara, Turkey at noon one day, it will pass over Valencia, Spain 101 minutes later the same afternoon—and it will pass over Ankara again 26 days later. Each satellite can record images of places as far north as the northern tip of Greenland and, in the south, all but the center of Antarctica. To do this, it uses two camera-like devices that scan a ground area of 60 by 60 kilometers (1400 square miles) in either 3000 or 6000 squares called pixels. The cameras are equipped with steerable mirrors so that scans can be made as much as 27 degrees off the vertical; this makes it possible to produce stereoscopic images if desired. The scans are beamed down to a ground station in digital form, where they are corrected for distortion. Stored in a computer, they can be retrieved and processed at space imagery rectification centers into a wide variety of maps and images.

This article appeared on pages 12-19 of the March/April 1995 print edition of Saudi Aramco World.


Check the Public Affairs Digital Image Archive for March/April 1995 images.