>


<dt>additive</dt>
<dd><p>The name of the variable in <code>ssn.object</code> that is used
to define spatial weights. Can be quoted or unquoted. For the tailup covariance functions, these additive
weights are used for branching. Technical details that describe the role
of the additive variable in the tailup covariance function are available
in Ver Hoef and Peterson (2010).</p></dd>


<dt>mean</dt>
<dd><p>A numeric vector representing the mean. <code>mean</code> must have length 1
(in which case it is rec