Laudatio for Prof. Baarda

on the occasion of presenting the Levallois Medal

Delft, 17. November 1995

by Wolfgang Torge, IAG Honorary President

Levallois Medal 1995 for Professor Willem Baarda

At the XXIst IUGG General Assembly held in Boulder, Colorado, July 1995, the IAG Levallois Medal has been awarded to Professor Willem Baarda in recognition of distinguished service to the Association and to the science of geodesy in general. This was announced by the IAG President at the opening ceremony of the IAG General Assembly on July 3rd, 1995. The Netherlands Geodetic Commission organized an afternoon event on November 17th 1995 at Delft University of Technology, where the Levallois Medal was presented to Professor Baarda by the past IAG President Wolfgang Torge, in conjunction with an invited lecture entitled "The development of the geoid concept and its realization in Europe -200 years of international collaboration". The laudatio for Professor Baarda is printed below.

Mr. President of the Netherlands Geodetic Commission,

Dear Professor Baarda,

Dear Colleagues of the Dutch Geodetic Community,

Ladies and Gentlemen,

in 1979, the International Association of Geodesy established the award of the Levallois Medal, in order to honour our former Secretary General and his out-standing contributions to geodesy. The award is made in recognition of distinguished service to the Association, and/or to the science of geodesy in general. The medal shall be normally awarded at four year intervals, on the occasion of the General Assemblies of the International Association of Geodesy and the International Union of Geodesy and Geophysics. Between 1979 and 1991, the award was given to Charles Whitten/USA, Rudolf Sigl/Germany, Arne Bjerhammar/Sweden, and Paul Melchior/Belgium.

In 1994, the IAG again set up a Nomation Committtee consisting of the IAG Honorary Presidents. The committee proposed, and the IAG Executive Committee confirmed that the Levallois Medal 1995 shall be awarded to Professor Willem Baarda. This was announced by the IAG President at the opening ceremony of the IAG General Assembly in Boulder, Colorado, on July 3rd, 1995. As Professor Baarda could not attend the General Assembly, I am glad and grateful that the Netherlands Geodetic Commission organized this afternoon's event, thus giving me as the IAG past President the opportunity to personally present the medal to you, Professor Baarda.

It is in no way possible within our limited time frame to review here in full detail all your scientific work over nearly 50 years and your contributions to geodesy and surveying engineering. This was done comprehensively at the celebration of your 65th anniversary, and I shall limit myself here to only recall some highlights of your major scientific achievements, and your engagement in IAG.

You were the first to develop a systematic framework of statistical quality control for geodesy, and the famous "data snooping" among others, since many years is part of testing procedures applied in geodesy and surveying. You firstly introduced criterion matrices for testing a network precision, and you invented the reliability concept, now at widespread use. I also mention the invention of the S-transformations nowadays employed at "free-network" adjustments. At the end of the 1970's, you even extended your broad field of interest, looking from a very profound point of view closer on the links between geometric and physical geodesy. The coupling and interaction between those two sides of the same coin, which for many decades were considered rather separately, again is the topic of your most recent publication. Looking through the geodetic literature, we easily recognize that your work is part of the fundamentals of our science, and that in addition many of your concepts entered into all fields of the practice of our profession, providing a more solid basis and offering new possibilities for our engineering tasks. This is also in line with the more recent IAG policy to intensify our relations to the sister organisations in the field of engineering and cartography, in addition to our scientific and organisational links to the Earth sciences.

This brings me to Prof. Baarda's services for IAG. It was a fortune for the Association that already in the 1950's you not only engaged yourself in FIG, but also in IAG. Thereby you followed the great tradition of Dutch geodesists, who until today contribute significantly to the Association's work, since the Netherlands from the very beginning participated in the discussions on the "Mitteleurop!ische Gradmessung", and in 1865 officialy joined this organisation. With the names of van de Sande Bakhuyzen, Secretary General between 1900 and 1916, and Vening Meinesz, President between 1933 and 1946, two outstanding representatives of the Netherlands must be mentioned here, who especially succeeded to not only maintain the idea of international cooperation during wartime but also to manage the continuation of important services.

Prof. Baarda, first of all, engaged himself in several IAG Special Study Groups. These Groups represent the forefront of the Association's scientific work, and your membership in the SSG's on "Numerical Computations of Large Triangulation Networks", "Computer Techniques in Geodesy" and "Mathematical Structure of the Gravity Field", as well as your long (1963 - 1979) chairmanship of the SSG on "Statistical Methods as applied to the Specification of Networks" clearly reflect your main research areas, but also the intention to implement scientific achievements into practical work. As a member of the IAG "Continental Networks" Subcommission you contributed to the long standing IAG attempts to unify the geodetic systems in Europe, thus also demonstrating to other regions of the world how to transfer scientific and technological progress into operational systems, by exploiting international cooperation and organisation.

As a highly engaged University Professor, IAG also benefitted from your engagement in the Commission on Education, where you brought in your enthusiasm and skill in teaching. Last but not least I mention your membership in two Cassinis Committees. Every 8 years, this Committee shall review the structures of IAG and propose eventual changes to the Executive Committee and to the Council, thus securing a continous revision and renewal of our Association. You worked in the first (1960 - 1963) and in the second Cassinis Committee, when important decisions about the IAG reorganisation were made, and thus contributed in keeping our Association vivid.

Through the Levallois Medal, IAG honours your outstanding scientific contribution to geodesy and expresses its gratitude for your strong engagement in our Association.

I have the great pleasure and honour, to hand over now the Levallois Medal and the related certificate to you, Professor Baarda. The certificate reads:

The International Association of Geodesy awards

the Levallois Medal

to

Professor dr. ir. Willem Baarda

in recognition of distinguished service to the Association and the science of geodesy in general

XXIst IUGG/IAG General Assembly,

Boulder, USA, July 1995

Wolfgang Torge, IAG-President.

I congratulate you personally and on behalf of the IAG Bureau and the Executive Committee, to this award, and I connect this congratulation with the best wishes for your future.