The observed gravity grid of Canada shows variations in the gravity field largely caused by the shape and rotation of the Earth. Systematic gravity mapping began in Canada in 1944 and is ongoing. All data are tied to the International Gravity Standardization Network 1971.

This grid represents the observed gravity field over Canada. The data were compiled from the holdings of the Canadian Geodetic Information System maintained by the Geodetic Survey Division, Geomatics Canada. They were collected to map the variation in gravitational attraction over the Canadian landmass and offshore areas. Variations in the force of gravity are due to variations in the mass of underlying materials, however, the gravitational effect of the Earth's shape dominates over the contribution to the field by geological features. The gravity field is also used to define the geoid, which is the ideal shape of the Earth, or mean sea level if the Earth were completely covered with water.

The data used to compile this grid consist of approximately 660 000 gravity observations, including 165 000 on land, acquired between 1944 and 1999. The data spacing ranges from less than 1 km to over 20 km, with an average spacing between 5 and 10 km. All measurements were reduced to the IGSN71 datum.

Miles, W.F., Roest, W.R., and Vo, M.P., 2000. Map of Bouguer Gravity Anomalies, Canada. Geol. Surv. Canada Open File 3830a.

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