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COMPENDIUM INCLINATION MEASUREMENT
WYLER AG, WINTERTHUR / SWITZERLAND

1.12 EFFECT OF GRAVITATIONAL FORCE AND COMPENSATION WITH
INCLINATION MEASURING INSTRUMENTS
The inclination displayed by inclination measuring instruments and
sensors is based on the gravitation. However, gravitational force is
not consistent around the globe, varying with latitude and height
above sea level. Furthermore, variations of the density in the lithos-
phere cause additional local deviations.
As an example, the gravity at sea level is
• 9.78033 m/s at the equator
2
2
• 9.80620 m/s at 45 degree of latitude
2
• 9.83219 m/s at the poles
In the table below the values of gravity for some cities are listed.
Amsterdam 9.813 Istanbul 9.808 Paris 9.809
Athens 9.807 Havana 9.788 Rio de Janeiro 9.788
Auckland 9.799 Helsinki 9.819 Rome 9.803
Bangkok 9.783 Kuwait 9.793 San Francisco 9.800
Brussels 9.811 Lisbon 9.801 Singapore 9.781
Buenos Aires 9.797 London 9.812 Stockholm 9.818
Calcutta 9.788 Los Angeles 9.796 Sydney 9.797
Cape Town 9.796 Madrid 9.800 Taipei 9.790
Chicago 9.803 Manila 9.784 Tokyo 9.798
Copenhagen 9.815 Mexico City 9.779 Vancouver 9.809
Nicosia 9.797 New York 9.802 Washington 9.801
Jakarta 9.781 Oslo 9.819 Wellington 9.803
Frankfurt 9.810 Ottawa 9.806 Zurich 9.807
An inclination measuring instrument or sensor will be calibrated at the head office of WYLER AG in Win-
terthur. The inclinations displayed are exact only in this location. In different locations the displayed value
must be corrected. If the correction of the local gravity is switched on, the inclination measured will be
corrected accordingly before the value is displayed.

The correction is calculated according the following formula:
whereby
g gravity at the location of calibration
c
 displayed inclination at location of measurement
m
g gravity at the location of measurement
m
 effective inclination
eff
For further information about the effect of gravitational force and compensation with inclination measu-
ring instruments, see appendix at the end of the compendium.

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