./polygon.pl "29.45, 89.43" "32.47, 90.98" "27.25, 95.63" "27.29, 98.27" "36.74, 96.32" "31.90, 87.67" "29.45, 89.43" < datafile

#!/usr/bin/perl

use Math::Polygon::Calc;

# Each argument is a point on the polygon like "94.3,37.2"
foreach $argnum(0 .. $#ARGV)
{
        my @point=split( /\s*,\s*/, $ARGV[$argnum]);

#       printf("point %d: (%s)= [%s, %s]\n", $argnum, $ARGV[$argnum],
#               @point[0], @point[1]);

        push(@poly, [ @point[0], @point[1] ]);
}

# The last point needs to be the same as the first
@poly[ $#ARGV + 1 ] = [ @poly[0]->[0], @poly[0]->[1] ];

foreach $line(<STDIN>)
{
        my @arr=split(/\s+/, "$line");

        @arr[8] =~ s/[A-Z]//g;
        @arr[9] =~ s/[A-Z]//g;

        polygon_contains_point([ @arr[8], @arr[9] ], @poly) &&
                print "$line";
}

exit 0;

$ ./poly.pl "29.45, 89.43" "32.47, 90.98" "27.25, 95.63" "27.29, 98.27" "36.74, 96.32" "31.90, 87.67" < data
   BDA 1908  8 20  9 53  0.00  32.0000N  89.0000E  60.0   0 0.00   0 0.00 0.00  6.60   0  7.00  7.00   0 NULL
   SIG 1927  5 22  0  0  0.00  36.0000N  96.0000E   0.0   0 0.00   0 0.00 0.00  7.50   0  8.00  8.00   0 NULL
   BDA 1934 12 15  1 57 37.00  31.3000N  89.3000E  60.0   0 0.00   0 0.00 0.00  6.70   0  7.10  7.10   0 NULL
   G-R 1950  8 15 14  9 30.00  28.5000N  96.5000E  25.0   0 0.00   0 0.00 0.00  8.10   0  8.70  8.70  10 NULL
   ISS 1950  9 13 11  7 27.00  27.5000N  96.4000E   0.0   0 0.00   0 0.00 0.00  6.60   0  7.00  7.00   7 NULL