Centennial Celebration of the Finnish Geodetic Institute

The Finnish Geodetic Institute (FGI) was established on 5 July 1918, just seven months after Finland gained its independence. The main task of FGI was the basic mapping of Finland, later to include precise levelling for the national height system, gravimetric measurements for the gravity system, and extensive research in the field of geodesy. Over the decades, FGI has conducted or participated in several important national and international measurement campaigns. With the organisation celebrating its hundredth anniversary this year, this article reflects on its history and concludes that FGI is now stronger than ever – ready for the challenges of this new century.

The first-order triangulation had to start from scratch, requiring the selection and reconnaissance of the measurement sites, construction of towers, measurements and computation, astronomical measurements for positioning the network, and baseline measurements to determine the scale of the network. The measurements were started in May 1919, with the last measurements taken in 1987 in Northern Lapland. Ten years after the last triangulation observations, the geodetic control network was replaced by a network of permanent GNSS stations – FinnRef – which nowadays forms the basis of the national reference frame created and maintained by FGI.

Due to the Fennoscandian postglacial rebound, land uplift is almost 1cm per year on the west coast of Finland. Hence the national height system had to be renewed every few decades utilising precise levelling techniques. Nowadays, uplift can be measured using the time series obtained from the GNSS stations of the FinnRef network.

Gravity measurements

FGI initiated gravity measurements in 1924 using pendulum instruments. Later relative gravity measurements were made using spring gravimeters, and since the late 1980s with an absolute gravimeter. A total of 35,000 gravity points have been measured and this database is now used for computation of the gravimetric geoid. The world-famous work of Professor Veikko A. Heiskanen, who later became the director of the Geodetic Institute at the Ohio State University in 1950, on isostasy and global geoid was also a reason why FGI became well-known within the geodetic community. Although Heiskanen was for only the director of FGI for a short time, his influence on geodesy in Finland has been considerable.

Over decades FGI has conducted or participated in several important national and international measurement campaigns. Metsähovi Observatory was established and SLR observations were started in 1978. Gradually, Metsähovi developed into a comprehensive geodetic research station with a GPS receiver in the IGS network, a DORIS beacon, a gravity lab, and auxiliary and environmental monitoring instruments. In 2012, using special investment funds, a programme commenced to modernise all major instruments, including the SLR and the superconducting gravimeter. A new VLBI radio telescope is under construction, and is expected to be operational in 2019.

Finnish Geospatial Research Institute

The new millennium ushered in significant changes at FGI. Four new departments replacing the old ones were established in 2001: Geodesy & Geodynamics, Geoinformatics & Cartography, Remote Sensing & Photogrammetry, and Navigation & Positioning. The number of personnel has grown from about 45 in 1995 to 140 in 2018. The strategic research areas were defined to be Reference Systems, Mobile Geomatics, Spatial Data Infrastructures, and Changing Earth. The biggest change occurred in 2015 when FGI merged with the National Land Survey (NLS) of Finland. At the same time the name was changed to the Finnish Geospatial Research Institute, preserving the well-known abbreviation FGI. FGI has become a research unit within NLS, and is now stronger than ever – ready for the challenges of this new century.

This article was written by Markku Poutanen, FGI