optional, single

—

With <averagevisibility> the average visibility at the dive spot described is put into bracksts. The value is given in metres as a real number.

<sitedata>

—

<maximumvisibility>, <minimumvisibility>, <sitedata>

(see also <sitedata>)

<!-- average visibility 5 metres -->
<averagevisibility>5.0</averagevisibility>