##
POLY_AREA

The
POLY_AREA function returns the area of a polygon given the coordinates of its vertices. This value is always positive.

It is assumed that the polygon has *
n*
vertices with *
n*
sides and the edges connect the vertices in the order:

[(x1,y1), (x2,y2), ... , (x*
n*
,y*
n*
), (x1,y1)]

such that the last vertex is connected to the first vertex.

This routine is written in the IDL language. Its source code can be found in the file ```
poly_area.pro
```

in the ```
lib
```

subdirectory of the IDL distribution.

###
Calling Sequence

Result = POLY_AREA(*
X, Y*
)

###
Arguments

####
X

An *
n*
-element vector of X coordinate locations for the vertices.

####
Y

An *
n*
-element vector of Y coordinate locations for the vertices.