Finding the area of a irregular polygon (SAS Base)

[brophymj]

I have sas/stat and sas foundations but not sas/iml

I'm trying to find the area for an irregular polygon. My dataset consists of many points but the example below contains just 8 coordinates.

Is there a good algorithm available for doing this? Ideally generalizing it so that it can apply to potentially 100s of points.

data coord;

input x 1. y 1.;

datalines;

14

31

53

87

79

58

47

25

run;

[ballardw]

This paper may provide a starting point. http://www.caloxy.com/papers/52-DataX_gis_poster.pdf

It has a few pages worth of code to do this and find "interior" points. The code dates from the 80's and doesn't use proc gis or similar.

Understanding the code may be a learning exercise.

[Jay54]

http://blogs.sas.com/content/graphicallyspeaking/2015/08/24/a-macro-for-polygon-area-and-center/