International Service for the Geoid


Search in ISG Website



Services - Geoid Repository

Regional Models

Baltic and Nordic Region Region (NKG2015)

  Authors: J. Agren, et al.     Created: 2015    Resp: J. Agren  
      Status: PUBLIC    
The NKG2015 gravimetric quasigeoid model for the Nordic-Baltic countries has been developed by the Nordic Geodetic Commission ( It is referred to the GRS80 ellipsoid (ETRF2000 frame, epoch 2000.0) and it extends from 53°N to 73°N and from 0°E to 34°E with a grid spacing of 0.6'x1.2'. With respect to the previous NKG2004 version, the NKG gravity database has been thoroughly modernized and updated since 2010. A new regional NKG digital elevation model with 3"x3" resolution has been compiled, along with an ice thickness model derived for the glaciers in Norwegian mountains. A new NKG GNSS/levelling database has also been created. The NKG2015 quasigeoid determination is based on the least-squares modification of Stokes’ formula with additive corrections (LSMSA) in the framework of a remove-restore procedure, using the GOCE/GRACE geopotential model GO_CONS_GCF_2_DIR_R5 up to degree and order 300. The resulting model has been fitted to GNSS/levelling data with a 1-parameter transformation and a permanent tide correction. After that, the NKG2015 quasigeoid model agrees with GNSS/levelling data with a standard deviation of 2.9 cm (1.5-2.0 cm on land).

J. Agren, G. Strykowski, M. Bilker-Koivula, O. Omang, S. Mardla, R. Forsberg, A. Ellmann, T. Oja, I. Liepins, E. Parseliuas, J. Kaminskis, L.E. Sjoberg, G. Valsson (2015). The NKG2015 gravimetric geoid model for the Nordic-Baltic region. Presented at the 1st Joint Commission 2 and IGFS Meeting, 19-23 September 2016, Thessaloniki, Greece.

Nordic and Baltic Countries