<para>

returns a boolean value that signifies whether the points

<parameter>p1</parameter> and <parameter>p2</parameter>

lie within distance <parameter>radius</parameter> of each other, i.e.

lie within distance <parameter>radius</parameter>(in radians)of each other, i.e.

it computes the boolean expression <literal>p1 &lt;-> p2 &lt;= radius</literal>.

On PostgreSQL 12 and later, the function has <literal>GiST</literal>

support and the PostgreSQL optimizer will transform it to either