ent" -->
<p>Some method arguments take various objects for convenience.
This appendix discusses the detail of acceptable value.</p>
<dl>
<dt><a name="label-85" id="label-85">should be Float</a></dt><!-- RDLabel: "should be Float" -->
<dd>
Any object that respond to <code>to_f</code> is converted to Float.
String is not acceptable.
<code>nil</code> is treated as -2e-38 (NODATA) for <var>m</var> (measure) coordinate,
or as 0.0 otherwise.
</dd>
<dt><a name="label-86" id="label-86">type of shapes</a></dt><!-- R