Draft:Jacob Menno Tienstra

Jacob Menno Tienstra (Sneek, 7 April 1895 – Delft, 15 September 1951) was a Dutch geodesist. He was full professor in "land surveying and spirit leveling" (geodesy) at Delft University of Technology, at the time "Technische Hogeschool Delft."

Biography
Tienstra was born in 1895 in Sneek, the Netherlands. In 1913 he completed the Higher Civic School (Dutch: Hogere Burgerschool, HBS). Initially he wanted to study chemistry, but the costs for such an education were too high. A surveyor living with the Tienstra family offered an alternative. He helped Tienstra to prepare for the exam as deputy surveyor at the land registry (Dutch: Kadaster), which he passed the same year. During his mobilization in the First World War, he was given the opportunity to study independently, after which he obtained the K-I mathematics certificate in 1917. The following year he passed the surveyor's examination at the land registry and in 1922 he obtained the K-V mathematics certificate. Tienstra, who was employed as a surveyor at the land registry in Sneek, was transferred to Zutphen in 1919. In the same year he married Wilhelmina Akke Nieveen.

In 1925 he was transferred again. This time to Amsterdam, which enabled him to attend lectures in mathematics and physics at the university during the period 1926 to 1928. In Amsterdam he was appointed Chief of the newly established Cadastral Survey of Amsterdam. Through this position he became friends with the Delft professor Willem Schermerhorn. During the same period, Tienstra began his theoretical research on the challenges of adjustment in surveying. His first publication in 1926 focused on addressing the intersection problem through the use of conditional equations, which led to several publications.

Academic life
In 1931, Tienstra was appointed as a lecturer to the Surveyors School which was at that time attached to the Agricultural University of the Netherlands in Wageningen, where he was responsible for courses in surveying. Due to budget cuts due to the great depression in the Netherlands, students who took the course could no longer be employed by the land registry. As a solution, Tienstra and Schermerhorn managed to obtain the status of civil surveyor. This required a special notification on their diploma and both gentlemen had to take an oath before the mayor of the students' place of residence. This made it easier for students to find a job at the land registry.

The death of Tienstra's boss professor J.W. Dieperink in 1934 triggered a debate about the location and scope of geodetic training in the Netherlands Ultimately, it was decided to discontinue the program in Wageningen. The Technical University in Delft filled this gap by offering an educational program in surveying at the faculty of civil engineering. Yet, the special surveyor's degree required 3.5 years of study at Delft, instead of the regular engineering degree which required five years of study. The planned five year curriculum for geodetic engineer at TU Delft was canceled because the Ministry of Finance did not intend to pay the land surveyors the salary of an engineer. Following these developments, in which Tienstra himself was involved, he was appointed as a part time professor at Delft Technical University. He was appointed full professor on January 1, 1939. In 1946 he was appointed rector magnificus at the Technical University Delft, but that same year it was determined that Tienstra was ill. He was able to resume his position in April 1947, after which he was succeeded later that year by Hein Israël Waterman. In 1948 he managed to set up a five year university curriculum for geodetic engineering at the Technical University Delft, which made it possible to obtain a doctorate. The same year he lobbied for Schermerhorn's plan to establish the International Center for Aerial Survey.

Due to a conflict between students and the management of TU Delft, he was appointed acting rector in 1950, after which this conflict was eventually resolved. In 1951 he became ill again; he died in September of the same year.

Selected publications

 * By Tienstra


 * J.M. Tienstra (1931). Het gebruik van de methode der kleinste kwadraten in de landmeetkunde, Wageningen: Veenman
 * J.M. Tienstra (1935) Foutentheorie en vereffening met betrekking tot de landmeetkunde, Delft, N.V. Drukkerij Waltman
 * J.M. Tienstra (1946) Rapport concentratie landmeetkundige diensten, Den Haag
 * J.M. Tienstra (1956) Theory of the adjustment of normally distributed observations, Amsterdam: Argus (Published after his death, edited by his friends)


 * About Tienstra


 * W. Schermerhorn (1951). Pays-Bas. Obituary: Professor Jacob Menno Tienstra, Volume 22, Issue 1, pp 377-380, Bulletin Géodésique
 * W. Baarda; onder redactie van K.F. Wakker (2002). Delfts goud: leven en werk van achttien markante hoogleraren, Technische Universiteit Delft: Delft, p. 123 t/m 134

Referenties

 * W. Baarda; onder redactie van K.F. Wakker (2002). Delfts goud: leven en werk van achttien markante hoogleraren, Technische Universiteit Delft: Delft, p. 123 t/m 134