.. highlightlang:: us

.. _polyarea:

polyarea
========

.. index:: polyarea

.. us.tag  polyarea ENGLISH New331

:ref:`polyarea` returns the area of a simple polygon specified by the vertices in
the vectors X and Y.

.. function::  rsA = polyarea(rvX, rvX)

.. us.return

**Return Value**

*rsA* is the area.

.. us.params

**Parameters**

.. uparam:: rvX

   *rvX* is a real vector.

.. uparam:: rvY

   *rvY* is a real vector.

.. us.comment

**Comment**

The area is a postive value. The polygon will be closed if the last vertex (xN,yN)
is not the same as the first vertex. The only restriction that will be placed on
the polygon for this function to work is that the polygon must not be self
intersecting. Note for polygons with holes. The holes are usually defined by
ordering the vertices of the enclosing polygon in the opposite direction to
those of the holes.

.. us.example

**Example**

::

   xx = linspace(0, 2.0*PI, 6);
   x = cos(xx);
   y = sin(xx);
   A = polyarea(x, y);
   rvH = plot(xv,yv);
   Createtitle("Area = " + strtod(A))

.. seealso::
   :ref:`overview-mathematic`

:sub:`id-726682`