Professor Torsten Hägerstrand

Geographer who revolutionised the study of population movements
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The Independent Online

Torsten Hagerstrand was a dominating scholar in geography worldwide who worked tirelessly for co-operation across the sciences.

Stig Torsten Erik Hägerstrand, geographer: born Moheda, Sweden 11 October 1916; Professor of Human Geography, Lund University, 1957-71, HSFR Research Professor 1971-82 (Emeritus); married 1944 Britt Lundberg (one son, two daughters); died Lund, Sweden 3 May 2004.

Torsten Hagerstrand was a dominating scholar in geography worldwide who worked tirelessly for co-operation across the sciences.

As Professor of Human Geography at Lund University in Sweden, Hägerstrand pioneered important innovations in the spatial study of population movements. Under his influence, Swedish universities set the agenda for new research developments in human geography from the 1960s, making Lund for some decades the Mecca for young graduate students from around the world. As a leader of the European Science Foundation and a founder member in 1988 of the Academia Europaea, Hägerstrand was a powerful advocate for bringing disciplines together to study emerging European regional problems.

He was born in Kronoberg county in the forested Småland region of south-east Sweden in 1916, son of a rural schoolmaster. The infant Torsten's nursery was directly above the schoolroom and he recalled his earliest memories as trying to decipher from sounds coming through the floorboards the regular rhythms of the class below. This early fascination with pattern and timing was to colour many of his later interests, from spatial rhythms in the local landscape to the musical scores for his organ playing at the local church.

From these backwoods, he emerged in the mid-1930s to the unfamiliar, flatter and unwooded plains of Skane and the university city of Lund. With a broad span of curiosity about both the natural and cultural world, he chose to study geography, but hedged his bets by taking lectures in art history. Apart from a brief period in Stockholm, it was in Lund that he was to live and study for the rest of his life: as student, lektor, assistant professor, professor and research professor. His own migration from one region of Sweden to another, rural depopulation at one end of the spectrum, urban congestion at the other, fascinated and puzzled him and it became one of the leitmotivs running through much of his research.

After a year of military service he matriculated from Lund in 1937. Under the influence of the geographer Helge Nelson he began detailed research on migration from Asby parish in his home region, eventually tracking the detailed year-by-year spatial movement of every one of its 10,000 people for a full century from 1840 onwards. This huge logistical task was interrupted by further years of military service (Denmark and Norway were now occupied and Finland at war). It was eventually completed without the benefit of a computer, but with the patient help of his devoted fiancée, Britt Lundberg.

War also brought refugee scholars to Lund and among these the Estonian Edgar Kant was to be a decisive influence for Hägerstrand and greatly widened the range of subjects with which geography interacted, bringing in ideas from mathematics and economics as well as the traditional geology and history. The impact of the Second World War was borne in on the young and newly married Hägerstrands in their cycling expeditions which included the bombed cities of England: it was to leave a deep longing for better harmony among Europe's nations and academies.

Hägerstrand's earliest research contributions came in his doctoral dissertation on the spatial diffusion of innovations, a study of the way information moves through human populations. Here, both Nelson's concern for demographic sources and the Swedish landscape and Kant's mathematical influence came together. The first introduced Hägerstrand to the meticulous tracking of human migration movements over small areas of rural Sweden, and the second to probabilistic ideas on settlement patterns and the possibilities of modelling using Monte Carlo simulations.

The result was Hägerstrand's 1950 doctoral thesis published as Innovationsförloppet ur korologisk synpunkt in which the adoption of agricultural innovations by farmers in central Sweden was conceived as a series of diffusion waves whose passage could be mapped, modelled, simulated, and conditionally predicted. But, written in Swedish, the ideas embedded in the work were to remain as hidden as Småland forests in the English-dominated academic world for another decade.

An invitation to the University of Washington (then the hub of quantitative geography in the United States) allowed Hägerstrand to talk about his work. Also, in 1960 Sweden was one of the Nordic countries hosting the International Geographical Congress. Hägerstrand organised a highly successful symposium on urban modelling at Lund that brought together leading scholars from a score of countries; here it was the Swedish ideas that caught the imagination and were rapidly diffused around the world.

Following the IGU meeting, an invasion of the brightest North American students studied at Lund and Allan Pred (Berkeley) undertook translation of Hägerstrand's original thesis into English: as Innovation Diffusion as a Spatial Process (1967), it became a classic. Groups in the US and Britain raced to develop more and more powerful "Hager models" using the revolution in digital computing to generate Monte Carlo simulations of population movements which had previously been laboriously calculated by hand.

Meantime, Hägerstrand himself was moving on to fresh pastures in his "time geography". His appointment in 1971 to a prestigious personal research chair funded by the Swedish Humanities and Social Science Research Council (HSFR) allowed him the time and resources to turn from the large-scale study of aggregate time-space studies to the detailed dissection of individuals' movements over very short time periods. With his Lund colleagues such as Gunnar Törnqvist and Olof Wärneryd he was able to show how an understanding of changes in such individual trajectories at a micro-scale allows a clearer understanding of the changes in the aggregate geography of human spatial distribution, from industrial organisation to shifting cultivation.

Using Sweden's superb census records, he developed new methods of geo-coding and computer mapping, harnessing computer power to record geographical data in new and flexible ways. The present phenomenal power of Geographic Information Systems (GIS) to handle geographical data still has its roots in ideas pioneered by the Lund group.

Much of the Lund work was directed at specific regional restructuring within the Swedish economy. Local government areas were being redrawn, hospital and school catchment areas optimised, the impacts of transport changes forecast, industrial linkages redrawn. All these developments drew Hägerstrand increasingly into regional planning and government advisory work on future population changes both at national and European levels. But, if his work was sometimes seen to be part of Sweden's reorganising crusade, he reflected increasingly in his writings a concern for individual choice and an anxiety that model-based planning should not bury the individual voice or destroy regional identities.

For someone who was fired as much by fine poetry as fine mathematics, Hägerstrand was worried that the huge advances in 20th-century science were being won by disintegration and lack of contacts across the exponentially exploding academic fields. Typically he was one of the "gang of 12" scholars who gathered in London in August 1987 under the chairmanship of the Cambridge pharmacologist Arnold Burgen to launch what would become the Academia Europaea. Today its many thousand members come from 40 countries and range in subjects all across C.P. Snow's "two cultures" from linguistics to neuroscience.

Inevitably Hägerstrand's decades of sustained contributions and public service were recognised in later years by a swathe of awards. The Anders Retzius, Vitus Bering and Carl XVI Gustav medals and honorary degrees in Nordic countries were matched by similar recognition elsewhere. In Britain, he was a Victoria Medallist of the Royal Geographical Society, received doctorates from Bristol, Edinburgh and Glasgow, and was the first continental geographer elected as a Corresponding Member of the British Academy. He was one of the first to be awarded the Vautin Lud medal from France.

Torsten Hägerstrand remained at heart the schoolmaster's son from Småland. A gently spoken but commanding figure, diffident and encouraging of others but courageous in his own views, and a man with an enviable command of the main European languages, he was an obvious choice for chairing international committees. The OECD, Efta (the European Free Trade Association), the International Geographical Union, the European Science Foundation, the Council of Europe all made increasing demands on his time and his wisdom well into his retirement years. So also did the unrelenting flood of young graduates and overseas visitors who continued to beat a path to his door.

As a cultured Swedish scholar, he would have enjoyed more time for the poetry of Carl Bellman or the music of a Franz Berwald quartet, more family time at his summer retreat. But he continued to write research papers and to keep up a punishing multi-language correspondence nearly to the end.

In one of his last letters to me, he wrote of his satisfaction at living long enough to see the elegant road-rail bridge across the Oresund between Denmark and Sweden completed. He had computed its likely impact a generation before. That graceful structure stands today as a symbol of his own life's work: linking across disciplines, linking across generations, linking across Snow's two cultures.

His was a life which ignored boundaries and rejoiced in the joy of bringing both ideas and people together, of seeing pattern and order where others saw only chaos and randomness.

Peter Haggett