Klaus-Peter Schwarz, lAG President The University of Calgary The Scientific Assembly of the International Association of Geodesy (lAG) was held from September 3 to 9, 1997 in Rio de Janeiro, Brazil, in conjunction with the 18th Brazilean Congress of Carthography. This was the first time that one ofthe major lAG meetings took place in Brazil. It provided an opportunity to showcase the progress of geodetic work in South America through campaigns such as SIRGAS. It also provided an opportunity for a large group of international experts to present the state of the art in ge- odesy and geodynamis and to interact with their hosts on possibilities of future coopera- tion. For the lAG, it continued a trend, started in Beijing four years ago, to hold major geodetic meetings outside of Europe and North America. The International Geoid School which was held in Sao Paulo following this meeting showed another facet of this grow- ing internationalization ofIAG activities and services. The scientific program of the meeting consisted of three symposia and two special ses- sions, namely Symposium 1 : Advances in Positioning and Reference Frames Symposium 2: Gravity and Geoid Symposium 3: Geodynamics Special Session 1: lAG Services Special Session 2: Geodesy in Antartica. Papers presented at the first symposium are published in volume 1 of these proceedings, while papers of symposia 2 and 3 as well as special session 2 are contained in volume 2. Papers presented at special session 1 will be published separately.

Klaus-Peter Schwarz, lAG President The University of Calgary The Scientific Assembly of the International Association of Geodesy (lAG) was held from September 3 to 9, 1997 in Rio de Janeiro, Brazil, in conjunction with the 18th Brazilean Congress of Carthography. This was the first time that one ofthe major lAG meetings took place in Brazil. It provided an opportunity to showcase the progress of geodetic work in South America through campaigns such as SIRGAS. It also provided an opportunity for a large group of international experts to present the state of the art in ge- odesy and geodynamis and to interact with their hosts on possibilities of future coopera- tion. For the lAG, it continued a trend, started in Beijing four years ago, to hold major geodetic meetings outside of Europe and North America. The International Geoid School which was held in Sao Paulo following this meeting showed another facet of this grow- ing internationalization ofIAG activities and services. The scientific program of the meeting consisted of three symposia and two special ses- sions, namely Symposium 1 : Advances in Positioning and Reference Frames Symposium 2: Gravity and Geoid Symposium 3: Geodynamics Special Session 1: lAG Services Special Session 2: Geodesy in Antartica. Papers presented at the first symposium are published in volume 1 of these proceedings, while papers of symposia 2 and 3 as well as special session 2 are contained in volume 2. Papers presented at special session 1 will be published separately.

This selection of papers emphasizes the advances in the field and covers a wide range of topics in geophysics, geodynamics, and oceanography to which modern geodesy is contributing.