y-coordinate variable in <code>dframe</code>.  Note that
y-coordinates are required for calculation of the local mean variance
estimator.  The default value is <code>NULL</code>.</p></dd>


<dt>sizeweight</dt>
<dd><p>Logical value that indicates whether size weights should be
used during estimation, where <code>TRUE</code> uses size weights and
<code>FALSE</code> does not use size weights. To employ size weights for a
single-stage sample, a value must be supplied for argument weight.  To
employ size weights