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GEOID MODELLING IN THE SOUTHERN REGION OF THE 
BUENOS AIRES PROVINCE 
Raúl Perdomo*, Daniel Del Cogliano* 
Nilda Di Croche**, Esteban Napal**, Beatriz Aldalur**, 
Pablo Napal**, Irene Pintos** 
*Fac. de Cs. Astronómicas y Geofísicas UNLP, CONICET, La Plata 
**Dto. de Ingeniería UNS, Bahía Blanca 
ISPRS Commission VI Working Group 3 
Abstract 
During the end of 1997 and the beginning of 1998 a GPS network was measured in the South of 
Buenos Aires province. 
Most of the points of this network coincided with existing points of the Altimetric Network of the 
Country. 
Geoidal undulations were calculated using the ellipsoidal heights (h) obtained as the result of the 
GPS measurements and the orthometric heights (H) which were provided by the Military 
Geographic Institute. (N = h - H). The values of these geoidal undulations were compared with 
those obtained using the EGM96 global model. The range between the maximum and minimum 
differences was few centimeters. 
One aim of this work is to test the global geoid model for long and short distances and to detect 
critical zones where a densification of the observations is necessary to adjust the geoidal model in 
study. 
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