Casio verizon User Manual page 188

• The electronic compass uses the Earth's magnetic field to
determine direction. The direction readings produced by the
electronic compass can be different from actual compass readings
due to environment and temperature.
• Direction readings taken in any of the following locations may result
in very inaccurate readings.
- Near buildings (especially ferro-concrete structures), large metal
objects (trains, motor vehicles, etc.), high-voltage power lines, or
overhead wires
- Near metal objects (desks, lockers, etc.), household appliances
(TVs, computers, speakers, etc.), or permanent magnets
(magnetic necklaces, etc.)
If you suspect a reading error, move away from the above locations
and try again.
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