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Soren W. Henriksen (1916 - 2011)

Soren Henriksen died on Monday the 5th of September 2011.

Soren Werner Henriksen, one of the first to apply space age data to the mapping sciences, died September 5, 2011, at the age of 95. He was a polymath in the fields of geodesy, surveying, photogrammetry, cartography, and astronomy, his culminating achievement being “Glossary of the Mapping Sciences,” a 581 page compendium published in 1994.

Soren was born in New York, New York, on August 5, 1916, and grew up in Chicago, Illinois. In 1938 he joined the Illinois National Guard, and transferred in 1941 to the U. S. Army. He served until August 1945, after being severely wounded in the Philippines that summer. He entered the Illinois Institute of Technology next year, earning a Bachelor’s degree in 1949 in mathematics. A Master’s degree from the University of Illinois in 1950, continuing in mathematics, followed.

The U. S. Army Map Service (AMS), a component of the Army Corps of Engineers, was actively recruiting mathematicians at that time. The exigencies of the Cold War required improvements in knowledge of the figure of the Earth, intercontinental connections, and the Earth's gravity field. Soren joined AMS in 1951 and was assigned to the Occultation Section of the Research and Analysis Branch in the Geodetic Division. This was his fortuitous introduction to professional astronomy. He was lucky to have a first-rate mentor in John O'Keefe (BAAS, 2000. 32, 1683), the head of the Branch, whose expertise lay in the application of astronomical methods for position determination, in particular, lunar occultations and solar eclipses. Soren rapidly applied his mathematical skills to this area, and in 1955 was promoted to Chief of the Section. In addition to his operational duties of analyzing and reducing observational data, he authored the definitive manual on the subject: "The Application of Occultations to Geodesy," published as AMS Technical Report 46 in 1962.

Well before the first artificial satellite launch in 1957 O'Keefe had realized the tremendous advantage of observations from this source for geodesy and laid the ground-work for their utilization at AMS. Soren turned the attention of his Section to the development of satellite observing systems. He was largely responsible for the employment of Minitrack II and SECOR, mobile satellite tracking systems that could be readily shifted from one set of sites to another.

In 1960 he was promoted to Chief of Research and Analysis. The administrative and supervisory duties this entailed limited his opportunities for individual research, and at the beginning of 1965 he left for a position at Raytheon Autometric where he was able to apply his experience in satellite data analysis to the demands of various contractors. A typical contract report of this period coauthored by him was "Modes of Satellite Triangulation Adjustment." During his seven years at Autometric he received its Outstanding Author Award twice.

He helped organize the Third International Symposium on the Use of Artificial Satellites for Geodesy held in Washington, D. C., in April 1971, and coedited the proceedings, published as Geophysical Monograph 15 by the American Geophysical Union (AGU). Based on this accomplishment, in 1972 AGU asked him to serve as editor for a collection of articles covering NASA's National Geodetic Satellite Project. This turned out to be a two year task, during which Soren carried the load of assembling the 1030 page, two volume, compilation. After completion Soren returned to the Federal government as a research geodesist in the Geodetic Research and Development Laboratory at NOAA in 1974.

His work there covered a variety of topics including determination of polar motion, utilization of geoceiver observations, and photogrammetric applications. He applied his editorial skills to the 1980 edition of the "Manual of Photogrammetry" as an associate editor, and authored the entry on field surveys for photogrammetry. But the major efforts of his ten year stint at NOAA were devoted to the preparation of a glossary to supplant the classic “Definition of Terms Used in Geodetic and Other Surveys” by Hugh Mitchell published in 1948. Soren envisaged not just a revision and update, but a vastly increased encyclopedic dictionary, encompassing in addition to geodesy and surveying the related fields of cartography, map production, photogrammetry, and remote sensing. This ambitious scheme proved to be controversial, and the resulting publication "Geodetic Glossary", issued in 1986 by the National Geodetic Survey of NOAA, omitted many of the entries not directly related to geodesy.

Before then, Soren decided to leave and continue work on his own version. He took advantage of his eligibility for retirement in 1984, and in 1988 submitted his manuscript to a joint committee of the American Society of Photogrammetry and Remote Sensing (ASPRS), the American Congress of Surveying and Mapping, and the American Society of Civil Engineers (ASCE). Publication followed under the auspices of ASCE.

Soren participated actively in the life of several professional societies. He was a member of AGU, ASPRS, Institute of Electrical and Electronic Engineers, Royal Astronomical Society, and American Astronomical Society.

A prominent trait of Soren's was his competitiveness, both in and outside of his profession. Two of his favorite forms of recreation were duplicate bridge and the ancient Chinese board game, Go. After age limited his mobility, he turned to the challenge of computer games like Myst. He retained an interest in updating his glossary to the end. He is survived by his wife of 59 years, Pamelia, a daughter, Kirsten, and two grandchildren. A son, Donn, predeceased him.

Obituary Written By: 
Bernard Chovitz (Retired, National Geodetic Survey )
BAAS: BAAS, 2011, 43, 041