<para>
This option specifies the number of digits to be used when
writing geographic coordinates, .i.e., latitude and longitude.
Precision is the number of digits after the decimal point.  The default
precision is 6.  We limit the number of places we write to improve the
fidelity when round-tripping geographic coordinates, reduce file size, and reduce
silliness in files caused by repeating decimals in insignificant
digits.
</para>
<para>
As a guideline, at the equator, five decimal places is about 1.1 m,
placing it below the accuracy of commodity consumer GPS gear. Six places
is 0.11 m, achievable via surveyor grade and differential corrected GPS.
Seven is 11 millimeters.
</para>
<para>
This value is ignored on read and has no impact on the internal
representation of data.
</para>
