Sebastian Finsterwalder (4 October 1862 – 4 December 1951) was a German mathematician and glaciologist. Acknowledged as the "father of glacier photogrammetry"; he pioneered the use of

repeat photography Repeat may refer to: * Rerun, a rebroadcast of an episode of a radio or television program * Repeated sequence (DNA), a pattern of nucleic acid (DNA or RNA) that occurs in multiple copies throughout the genome ** CRISPR * The smallest rectangle t ...

as a temporal surveying instrument in measurement of the geology and structure of the Alps and their glacier flows. The measurement techniques he developed and the data he produced are still in use to discover evidence for

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

Life

Sebastian Finsterwalder was born 4 October 1862 in

Rosenheim Rosenheim is a city in Bavaria, Germany. It is an independent city located in the centre of the district of Rosenheim (Upper Bavaria), and is also the seat of its administration. It is located on the west bank of the Inn at the confluence of the ...

, son of Johann Nepomuk Finsterwalder, a master baker from

Antdorf Antdorf is a municipality in the Weilheim-Schongau district, in Bavaria, Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, a ...

near Weilheim,

Upper Bavaria Upper Bavaria (german: Oberbayern, ; ) is one of the seven administrative districts of Bavaria, Germany. Geography Upper Bavaria is located in the southern portion of Bavaria, and is centered on the city of Munich, both state capital and seat o ...

, and Anna Amman of Rosenheim. He died 4 December 1951 in

Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...

). He was a Bavarian

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

and surveyor. In 1892 he married Franziska Mallepell (d. 1953) from

Brixen Brixen (, ; it, Bressanone ; lld, Porsenù or ) is a town in South Tyrol, northern Italy, located about north of Bolzano. Geography First mentioned in 901, Brixen is the third largest city and oldest town in the province, and the artistic and ...

South Tyrol it, Provincia Autonoma di Bolzano – Alto Adige lld, Provinzia Autonoma de Balsan/Bulsan – Südtirol , settlement_type = Autonomous province , image_skyline = , image_alt ...

. Their two sons worked in similar fields; Richard Finsterwalder (1899-1963), Professor at the Technical University in Hanover and Munich, and Ulrich Finsterwalder (1897-1988), a

civil engineer A civil engineer is a person who practices civil engineering – the application of planning, designing, constructing, maintaining, and operating infrastructure while protecting the public and environmental health, as well as improving existing ...

. A keen mountaineer, Finsterwalder became interested, through the influence of his friend E. Richter, in alpine fossils as indicators of the geology and structure of the Alps and their glaciers. His desire for accurate, but also less costly, motion measurements on glaciers led him to glaciological applications of

photogrammetry Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant ima ...

geodesy Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...

. In 1886, aged 24, he received his doctorate from the University of Tübingen, under the guidance of the algebraic geometer

Alexander von Brill Alexander Wilhelm von Brill (20 September 1842 – 18 June 1935) was a German mathematician. Born in Darmstadt, Hesse, Brill was educated at the University of Giessen, where he earned his doctorate under supervision of Alfred Clebsch. He held a c ...

. Finsterwalder observed that Rudolf Sturm's analysis of the "

homography In projective geometry, a homography is an isomorphism of projective spaces, induced by an isomorphism of the vector spaces from which the projective spaces derive. It is a bijection that maps lines to lines, and thus a collineation. In general, ...

problem" (1869) can be used to solve the problem of 3D-reconstruction using point matches in two images; which is the mathematical foundation of photogrammetry. Finsterwalder pioneered geodetic surveys in the high mountains. At the age of 27 years he conducted a first glacier mapping project at Vernagtferner in the

Ötztal Alps The Ötztal Alps ( it, Alpi Venoste, german: Ötztaler Alpen) are a mountain range in the Central Eastern Alps, in the State of Tyrol in western Austria and the Province of South Tyrol in northern Italy. Geography The Ötztal Alps are arrayed ...

, Austria.

Research and applications of photogrammetry

Following the 1878 work of Italian engineer Pio Paganini and others, Finstenwalder advanced methods for reconstruction and measurements of three-dimensional objects from photographic images. He was appointed professor at the

Technical University of Munich The Technical University of Munich (TUM or TU Munich; german: Technische Universität München) is a public research university in Munich, Germany. It specializes in engineering, technology, medicine, and applied and natural sciences. Establis ...

in 1891, succeeding his teacher, A. Voss, at the Department of Analytical Geometry, Differential and Integral Calculus (remaining at the university for forty years until 1931). The next year, he married, and completed the first recording of the Bavarian glacier in

Wettersteingebirge The Wetterstein mountains (german: Wettersteingebirge), colloquially called Wetterstein, is a mountain group in the Northern Limestone Alps within the Eastern Alps. It is a comparatively compact range located between Garmisch-Partenkir ...

and the Berchtesgaden Alps. He applied the technique of

plane table A plane table (plain table prior to 1830) is a device used in surveying site mapping, exploration mapping, coastal navigation mapping, and related disciplines to provide a solid and level surface on which to make field drawings, charts and maps. ...

photogrammetry in addition to a conventional geodetic survey, assisted by the novel lightweight, accurate phototheodolite that he had developed for high-mountain applications. The device was based on the prototype phototheodolite developed by Albrecht Meydenbauer (1834-1921) for architectural applications. From 1890 Finsterwalder also employed

aerial photography Aerial photography (or airborne imagery) is the taking of photographs from an aircraft or other airborne platforms. When taking motion pictures, it is also known as aerial videography. Platforms for aerial photography include fixed-wing aircra ...

, reconstituting the topography of the area of Gars am Inn in 1899 from a pair of balloon photographs using mathematical calculations of many points in the images. In 1897 Finsterwalder addressed the

German Mathematical Society The German Mathematical Society (german: Deutsche Mathematiker-Vereinigung, DMV) is the main professional society of German mathematicians and represents German mathematics within the European Mathematical Society (EMS) and the International Mathe ...

, and he described some of the results of

projective geometry In mathematics, projective geometry is the study of geometric properties that are invariant with respect to projective transformations. This means that, compared to elementary Euclidean geometry, projective geometry has a different setting, pro ...

he was applying to photogrammetry. His theory of large triangle meshes became known as the "Finsterwaldersche fields method" (1915). His analytical approach was laborious however, prompting development of analogue instrumentation with stereo measurement permitting faster optical/mechanical reconstruction of the photographic data arrays to determine object points. This was assisted by new technology;

Carl Pulfrich Carl P. Pulfrich (September 24, 1858 in Burscheid, Rhine Province – August 12, 1927 in Baltic Sea, drowned when his canoe capsized) was a German physicist, noted for advancements in optics made as a researcher for the Carl Zeiss company in ...

's stereocomparator (1901) and Eduard Ritter von Orel's stereoautograph (1907), both instruments built by the company Carl Zeiss. In 1911 he took over the chair of descriptive geometry, turning down offers of appointment from Vienna, Berlin and Potsdam.

Aerodynamics

Felix Klein Christian Felix Klein (; 25 April 1849 – 22 June 1925) was a German mathematician and mathematics educator, known for his work with group theory, complex analysis, non-Euclidean geometry, and on the associations between geometry and group ...

commissioned Finsterwalder while the latter was professor of mathematics at the Munich polytechnic, to write on aerodynamics for his '' Enzyklopädie der mathematischen Wissenschaften mit Einschluss ihrer Anwendungen'' (EMW) (tr. 'Encyclopedia of mathematical sciences including their applications'). The article, which he submitted in August 1902, more than a year before the Wrights achieved

powered flight A powered aircraft is an aircraft that uses onboard propulsion with mechanical power generated by an aircraft engine of some kind. Aircraft propulsion nearly always uses either a type of propeller, or a form of jet propulsion. Other potential ...

is thus prescient in its insights into the mathematics behind this new field of engineering. Finsterwalder also worked with

Martin Kutta Martin Wilhelm Kutta (; 3 November 1867 – 25 December 1944) was a German mathematician. Kutta was born in Pitschen, Upper Silesia (today Byczyna, Poland). He attended the University of Breslau from 1885 to 1890, and continued his studies in Mu ...

(1867-1944) at the Institute in Munich to devise formulas relating to the lift on an

aerofoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...

in terms of the circulation round it. Kutta's habilitation thesis, completed in the same year, 1902, with which Finsterwalder assisted, contains the Kutta-Joukowski theorem giving the

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobil ...

on an aerofoil.

Glacier flow in the Ötztal Alps

In 1922 Finsterwalder mapped the topography of the Ötztal Alps focusing on two glaciers, i.e. Gepatschferner and Weißseeferner, using

stereophotogrammetry Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant ima ...

. During this work he discovered Ölgruben rock glacier and the rock glacier north of Krummgampenspitze. In 1923 and 1924 Finsterwalder measured a flow velocity profile across Ölgruben rock glacier. Because of Finsterwalder's efforts, Ölgruben rock glacier became the subject of a notably extended,

longitudinal study A longitudinal study (or longitudinal survey, or panel study) is a research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time (i.e., uses longitudinal data). It is often a type of obs ...

of flow velocity with high value in climate research, with repeat surveys undertaken by Wolfgang Pillewizer in 1938, 1939, and 1953 using photogrammetry, and which is still ongoing, employing modern satellite-based positioning techniques.Hausmann, H, Krainer, K., Brückl, E. and Mostler, W.(2007). Creep of Two Alpine Rock Glaciers – Observation and Modelling (Ötztal- and Stubai Alps, Austria). In: V. Kaufmann & W. Sulzer (eds), Proceedings of the 9th International Symposium on High Mountain Remote Sensing Cartography. Grazer Schriften der Geographie und Raumforschung, 43, Institute of Geography and Regional Science, University of Graz, 145-150. His son Richard assisted in the mapping project in the Ötztal Alps and went on to advance his father's studies.

Other contributions

Under his leadership the Bavarian International Commission for Geodesy undertook precise gravity measurements with relative gravimeters throughout

Bavaria Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total lan ...

Honours

* 1965 Finsterwalder High School in his birthplace Rosenheim was named after him. * Finsterwalder Glacier is named after him. * 1915 President of the German Mathematical Society. * 1943 awarded Helmert commemorative medallion for excellence by the German Association of Surveying. * 1938 Asteroid 1482 (Sebastiana) was named after him.

Publications

* Finsterwalder, S. (1890) "Die Photogrammetrie in den italienischen Hochalpen," Mittheilungen des Deutschen und Österreichischen Alpenvereins, vol. 16, nº 1, 1890, pp. 6–9 * Finsterwalder, S., Muret, E., (1901). Les variations périodiques des glaciers. VIme Rapport, 1900. ''Extrait des Archives des Sciences physiques et naturelles'' 106/4 (12), 118– 131. * Finsterwalder, S., Muret, E., (1902). Les variations périodiques des glaciers. VIIme Rapport, 1901. ''Extrait des Archives des Sciences physiques et naturelles'' 107/4 (14), 282– 302. * Finsterwalder, S., Muret, E., (1903). Les variations périodiques des glaciers. VIIIme Rapport, 1902. ''Extrait des Archives des Sciences physiques et naturelles'' 108/4 (15), 661– 677. * Finsterwalder, S., (1928) Geleitworte zur Karte des Gepatschferners. Zeitschrift für Gletscherkunde, 16, 20–41.

Literature and links

* Seligman, G. (1949) Research on Glacier Flow. An Historical Outline. Geografiska Annaler, Vol. 31, Glaciers and Climate: Geophysical and Geomorphological Essays, Wiley / Swedish Society for Anthropology and Geography pp. 228–238 * Kaufmann, V. (2012) The evolution of rock glacier monitoring using terrestrial photogrammetry: the example of Äußeres Hochebenkar rock glacier (Austria) ''Austrian Journal of Earth Sciences'' Volume 105/2 Vienna 2012 pp. 63–77 * Leather Charles Steger : Astronomical and Physical Geodesy Volume 5 of the "Manual of Surveying" (ed. Jordan Eggert Kneissl, publishing JBMetzler, Stuttgart in 1969. * Walther Welsch et al. evaluation of geodetic monitoring measurements. Manual of Engineering Geodesy (ed. M.Möser, H.Schlemmer et al.), Wichmann-Verlag Heidelberg, 2000. * G. Clauß, in: Zs. f. Vermessungswesen, 1932, S. 721-26 ( P ); * R. Rehlen, H. Heß u. M. Lagally, in: Zs. f. Gletscherkde. 20, 1932, S. IX-XXI ( P ) * O. v. Gruber, in: S. F. z. 75. Geburtstag, Festschr. d. Dt. Ges. f. Photogrammetrie, 1937; * M. Kneißl, S. F. z. 80. Geburtstag, in: Bildmessung u. Luftbildwesen 17, 1942, S. 53-64 ( vollst. W- Verz., 123 Nr. ) * ders., in: Zs. f. Vermessungswesen 77, 1952, S. 1-3 ( P ) * Richard Finsterwalder, in: SB d. Bayer. Ak. d. Wiss., 1953, S. 257; * ders., in: Geist u. Gestalt, Biogr. Btrr. z. Gesch. d. Bayer. Ak. d. Wiss...II, 1959, S. 65-69 ( L ) * G. Faber, ebd., S. 34 f. ( P ebd. III, S. 183); * Pogg. IV-VII a. – Slg. math. Modelle v. F. im Math. Inst. d. TH München.

References

{{DEFAULTSORT:Finsterwalder, Sebastian 1862 births Technical University of Munich faculty 1951 deaths People from Rosenheim 19th-century German mathematicians 20th-century German mathematicians Climate change in Europe German climatologists German glaciologists German ecologists Photogrammetrists German geomorphologists Photographers from Bavaria German topographers