Honorary Members of L.G. Snellius:

Ir. G. Homan
Student Homan was a board member of the inaugural board of the L.G. Snellius, beginning in 1940. As a first-year student, he was immediately appointed to the board of the newly founded society. After World War II, Homan collaborated with Ter Schiphorst to write the Snelliuslied.
During the war, Homan was the only one of the three board members who neither signed the loyalty declaration nor graduated. He went into hiding but soon returned to his parental home. There, he secured a false work assignment using a forged identity card for the National Triangulation Survey in Twente, under the leadership of Mr. Bruins. At Homan's home, the illegal newspaper Het Parool was printed.
After the liberation, Homan initially served as a deputy member and later as a member-secretary of the Delft Purification Committee.

prof. J.M. Tienstra (1895-1951)
Professor Tienstra began his career as a land surveyor with the Cadastre, where he oversaw the re-surveying of Amsterdam. In 1931, he accepted a position at the Agricultural College in Wageningen. Alongside Professor Schermerhorn, Tienstra was instrumental in establishing the land surveyor program at Delft in 1935. Initially appointed as an extraordinary professor, he became a full professor in 1939.
In 1945, he was named secretary of the Senate of the Delft University of Technology and, in 1946, became its rector magnificus. Despite falling ill during the 1946/1947 academic year, Tienstra continued his work as a professor until his passing. He played a pivotal role in guiding students during the turbulent period of April 1943, when a loyalty declaration was required to continue studies under the occupation. As a paternal figure, his influence shaped the students' perspectives. Ultimately, Tienstra advised geodesy students not to sign the declaration, stating:
"It is clear to me that those who do not sign face an uncertain future. But it is equally clear that signing does not guarantee a peaceful study; too much has happened recently. Therefore, I believe it is best not to sign."
In 1998, the Prof. J.M. Tienstra Research Prize was established to promote geodetic research in the Netherlands, honoring his enduring contributions to the field.

Prof. R. Roelofs (1905-1987)
Roelofs, a land surveyor for the Dutch Cadastre in the Dutch East Indies, became head assistant in the Laboratory for Geodesy in 1936. In 1942, he was appointed lecturer, and in 1946, he succeeded Prof. Schermerhorn as professor of Geodetic Astronomy and Photogrammetry. Renowned as the inventor of the Roelofs solar prism—a device for theodolites to facilitate solar observations—he retired in 1970.
Known for his gentlemanly demeanor, Roelofs delivered clear yet demanding lectures, standing at the lectern. A devoted scientist, he maintained connections with leading geodesists and actively supported Snellius in organizing events. For example, he played a key role in planning the 1970 excursion to Paris and the Marine Geodesy information day, where his extensive network of contacts contributed to a robust program.
His book, Astronomy Applied to Land Surveying (1950), gained international acclaim for its clarity and practical insights, becoming a vital resource for geodetic engineers worldwide, particularly those working in remote areas. Upon retiring in September 1970, he distributed his extensive book collection among colleagues and relocated to a village in North Brabant. His last known appearance in the geodesy community was at the opening of the new department building in November 1976.

J.W. ter Schiphorst
Ter Schiphorst, a former chairman of the Snellius board (1946-1947), co-composed the Snellius song with Homan and designed the Snellius emblem. He humorously recounted how his fascination with Willebrord Snellius' Cyclometricus led to a pivotal "dream" collaboration with the mathematician’s spirit, solving a seemingly impossible geometric assignment during a summer camp in 1947. This creative solution, later accepted as the only viable one, likely earned him honorary membership, which he playfully credited to his “mascot-like” role. Ter Schiphorst worked in Sweden during his studies, met his future wife there, and later joined Stockholm's municipal administration. He eventually founded a company that mapped parts of Africa photogrammetrically. Despite his significant contributions, he remains the most enigmatic honorary member, with Homan losing contact with him in the 1970s.

N.D. Haasbroek (1899-1985)
Mr. Haasbroek was a surveyor at the Kadaster and took over leadership of the Amsterdam survey in 1931. In 1947, he became a lecturer at the TH, succeeding Prof. Roelofs, and retired in 1964. Known for his dedicated mentorship, he became a trusted advisor to students, offering guidance on academic, personal, and financial issues. Passionate about history, he published works on Willebrord Snel van Royen and the history of geodesy education. Haasbroek was deeply involved in student activities, delivering first-year lectures, and maintaining a personal connection with students. His sharp wit, dedication to language, and influential book Nomografie gained admiration internationally. Renowned for his supportive but firm approach, he encouraged struggling students to excel and left a lasting impression through his speeches, mentorship, and presence at academic and extracurricular events.

Prof. ir. W. Baarda (1917-2005)
Baarda worked as a surveyor for the Cadastre in Zwolle, where he contributed to mapping the newly drained Noordoostpolder and worked on the RD network in Delft. During the war years, he lived in a room in Zwolle, where he theorized about Mathematical Geodesy. Unfortunately, he no longer had access to his lecture notes from Professor Tienstra. According to Van der Hoek, “The year 1944 was probably his most fruitful period of thought. His entire subsequent scientific work was an elaboration of ideas from that time.” Baarda developed, among other things, the testing theory and modern point determination.
In November 1947, he was appointed as a lecturer. In 1952, he succeeded Tienstra as a professor after earning his Geodetic Engineering diploma in 1950. He had already graduated with distinction as a Civil Surveyor in 1939. From 1955 to 1959, Baarda served as Secretary-General of the FIG (Fédération Internationale des Géomètres). In 1956, he was made an Officer in the Order of Orange-Nassau. He became an honorary member of the Royal Institution of Chartered Surveyors in 1968 and of the Netherlands Association for Geodesy in 1981. He retired in 1982, at which time the commemorative publication "Daar heb ik veertig jaar over nagedacht..." ("I thought about this for forty years...") was released.

Mr. J.H. Jonas
Mr. Jonas, a mortgage registrar in Zutphen, was appointed as a lecturer in 1936 at the recently relocated surveying program. He taught the subject of law. A part-time staff member, Jonas was known for his convivial nature and his habit of treating others to rounds of drinks, famously a bottle of Bokma. In addition to his lecturing role at the Technical University, he also worked for the Cadastre in Rotterdam.

Prof. Ir. G.F. Witt (1912-1997)
In 1955, Mr. Witt was appointed professor of planning geodesy. Prior to this, he worked as a land surveyor for land consolidation at the Cadastre. Witt was named an honorary member due to his exceptional teaching abilities and was also the chairperson of the subdepartment. Professor Witt organized the only FIG (International Federation of Surveyors) conference held in the Netherlands in 1956. He is also an honorary member of the ‘Deutsche Verein für Vermessungswesen’ in recognition of his efforts to re-engage his German colleagues in the international geodetic community after the war.
"The student uprisings did not bypass the subdepartment, and as chair, Prof. Witt had to deal with very emotional events. These did not leave him unaffected and even posed a threat to his health" (Bogaerts). His response at the time to an invitation for the honorary members' lunch was: "My health does not permit me to indulge in such excesses anymore."

prof. ir. G.J. Bruins
Professor Bruins, after studying in Wageningen, became a land surveyor at the Cadastre in Delft in 1931. In 1933, he joined the maintenance service of the National Triangulation Survey. Between 1948 and 1951, he was part of Vening Meinesz’s gravity expeditions, which took place aboard submarines in the Atlantic Ocean. In 1951, he obtained his ‘Geodetic Engineer’ diploma and was appointed as a lecturer, replacing Baarda. In 1958, he was appointed professor of Physical Geodesy.

prof. mr P. de Haan
Professor de Haan began in 1962 as a professor of Civil and Agricultural Law at Geodesy. He brought about a significant expansion of the legal component within the Geodesy curriculum. In terms of hours, Law became the largest subject within Geodesy, and it became the largest law education program outside the law faculties at universities. He wrote all the study materials himself.
Initially, his specializations were Tenancy Law and Land Consolidation. De Haan later distanced himself from tenancy law and played an important role in the development of land management regulations, while also developing notable ideas in urban planning and urban renewal. Through his work in spatial administrative law, he naturally found his way into administrative law in general. The name of his chair was subsequently changed to reflect this shift. His books are illustrative of this development: the comprehensive Pachtrecht (Tenancy Law) (1969), a series of three volumes on spatial administrative law (1980s), and the ambitious Bestuursrecht in de Sociale Rechtsstaat (Administrative Law in the Social State) (1979, co-authored with two other authors).
Since retiring from Geodesy in 1988, he has remained very active as a publicist, writing articles on general, spatial, and agricultural administrative law, and further elaborating on Bestuursrecht. He also remained involved for many years in various important advisory roles related to agriculture, legal science, and land policy.
De Haan can be considered one of the most prominent Dutch legal scholars of the second half of the 20th century.

H.C. van der Hoek
Van der Hoek was a scientific staff member at the Department of Geodesy. He was born in 1926, an avid reader, and grew up in Rotterdam South. After working at the Central Drawing and Training Bureau of the Cadastre in The Hague, he joined the TH in 1952. In 1970, Van der Hoek was appointed an honorary member.
On December 19, 1984, Mr. Van der Hoek retired from the department. He gave his farewell speech in the Aula, where his romanticized childhood story was accompanied by slides of pre-war Rotterdam. A packed room listened attentively to his story, in which his wide-ranging interests once again came to the forefront. A festive booklet was published on the occasion of his retirement, clearly showing his fondness for gardening and Rotterdam South. Like Bruining and Daan Gast, Van der Hoek had not been part of the scientific staff, and their appointment caused some commotion.

A. Bruining
Bruining is an honorary member in recognition of his great and selfless commitment to students during and around their studies, just like Daan Gast. Both new honorary members were not part of the scientific staff, which caused some commotion within the faculty. It was always "Mister Bruining" and "Daan Gast." In 1960, Bruining attended the summer camp for the first time. After having participated in 27 consecutive camps, he retired in 1986. Bruining also served as a referee for the football tournaments for many years.

Daan Gast
Daan Gast is an honorary member in recognition of his great and selfless commitment to students during and around their studies. The new honorary members—the other being Mr. Bruining—were not part of the scientific staff, which caused some commotion within the faculty. The yellow geodesy bus, replaced in 1998, was known as Daan Gast's bus. In 1965, he attended the summer camp for the first time. In 1994, he celebrated his thirtieth and final summer camp, making him the record holder.

prof. dr. ir. G.H. Ligterink
After completing secondary school, Ligterink was sent to the Dutch East Indies as a soldier in 1947. When he returned in 1950, he wanted to study at the Technical University. However, he first had to take an admission test. Students receiving government financial support were assigned to a specific field of study based on this test. At that time, Mr. Ligterink did not know what geodesy was, and at the beginning of his studies, his motivation suffered due to his feeling of being forced into it. He worked as a student assistant to Professor Roelofs and helped map Terschelling using photogrammetry. This is where his passion for the field began.
Ligterink was a member of SSR-D, now the OJV 'De Koornbeurs'. He served as treasurer on the board of Snellius, which at that time consisted of only three members. The board organized excursions, which meant the treasurer had a significant responsibility, including carrying all the foreign currency.
Mr. Ligterink married in 1956. It was customary at the time to first graduate, then find a job, and only then marry. Ligterink worked for the Department of Geodesy for almost his entire life. During the traditional spear-throwing event at graduation, at one point, there was only one graduate. Mr. Ligterink, working in the department, also wanted to experience this. This led to his nomination as the opponent of the sole graduate. In 1992, upon his retirement, Professor Ligterink was appointed honorary member of the Dutch Association for Photogrammetry.

prof. ir. J.C. de Munck
Professor de Munck is a physicist. He was brought to the faculty by Professor Roelofs to develop the "Radial Triangulator," a photogrammetric instrument. From 1954 to 1958, he worked for the PTT in Kootwijk, after which he returned to the department. Various new technologies were introduced during this time, including electronic distance meters, radio positioning equipment, and satellite measurements. de Munck became an indispensable resource for these subjects.
In 1968, Ir. de Munck was appointed as a lecturer. He taught courses in Height Measurement, Electronic Distance Measurement, Radio Positioning, Marine Geodesy, and Optics & Electronics. In 1980, he was appointed a professor. He retired in 1989.

Prof. dr. G.J.C. Bots
During the tenth anniversary celebration 'Luuk,' Professor Bots was appointed as an honorary member. He had taught Mechanics to geodesy students for many years. "Professor Bots is known as a motivated and inspiring lecturer. His demonstration of the moment of momentum is particularly famous."

ir. G. Bakker
Bakker was the study advisor from 1984 to 1992, succeeding Van der Hoek. He was a member of the section of Physical, Surveying, and Spatial Geodesy. He was appointed as an honorary member in 1992, being the only honorary member not in a lustrum year. "But the main reason was simply the fact that he was always approachable to everyone. Not only students struggling with subjects, but also those facing personal difficulties, could turn to him" (letter to the General Assembly of the Board to nominate Bakker as an honorary member).

ing. Joop Gravesteijn
He has worked for most of the sections. Currently, he works at the section of Geoinformation and Land Policy. He completed the Elfstedentocht in 1985 and 1997. Regularly, he startles the building, including lecture halls, with his comical laughter.
"Joop always participates, always contributes, and always thinks along. It should also be mentioned that Joop excels at bridging the gap between students and staff at the faculty." (Report of the 11th lustrum). For many years, he has been active in the staff committee. Joop Gravesteijn is the man behind the skating competition and the staff’s laps during summer camps.
Dhr. J.J.M. Dukker

Prof.dr.ir. PJG Teunissen
Professor Peter Teunissen is highly regarded for his contributions in the design of algorithms that lie at the heart of all current GNSS products. He is the inventor of the LAMBDA method which revolutionized high precision GNSS positioning capabilities and which is currently the standard for fast and optimal ambiguity resolution.
Prof. Teunissen is also considered to be the founder of the statistical GNSS reliability theory of integer inference. Prof. Teunissen’s decorrelation-based method of integer bootstrapping is a popular alternative to search-based methods, and his easy-to-compute lower bound of the integer least-squares success rate is today still the sharpest known lower bound. His aperture estimation principle gives GNSS users control over their ambiguity failure rate, and provides guidelines/ rules on how to develop ambiguity resolution strategies when integrating different GNSSs and/or GNSS-like systems.
Prof. Teunissen’s leadership skills are reflected in his contributions to satellite navigation training. As director of education, he initiated the Aerospace Engineering Geomatics program in 2004. He is known as an excellent teacher. He has been a visiting professor at several universities in different countries to teach advanced courses on satellite navigation.
Peter Teunissen is Professor of Geodesy and Satellite Navigation at Delft University of Technology (DUT), The Netherlands, and Curtin University of Technology (CUT), Perth, Australia. He is science director of the Cooperative Research Centre for Spatial Information (CRCSI) contributing to the national positioning infrastructure. Prof. Teunissen is a Fellow of the Royal Netherlands Academy of Sciences (2000), and a Fellow of the International Association of Geodesy (1997). He is recipient of numerous awards and is currently a member of ten editorial boards. He has published six books and over 250 scientific papers.
Sources from here.