I've recently been asked to parse a collection of ESRI shape files to determine whether a given point falls within them.
"What luck!" I chortled, as I happened across jasonk's module.

Grabbing a sample shape file, I slapped together the example shown below.

The problem is, the X and Y point coordinates that I received seem to be wildly divergent from my expectations. Am I experiencing some kind of weird floating point problem, or do I need to convert my point values from some kind of projection? I was hoping for X and Y coordinates in terms of latitudinal and longitudinal degrees; solid, stable values like 44.234112 and -70.43101 -- the kind of numbers you wouldn't be ashamed to have over for dinner. Instead, I get numbers that I would be afraid to meet in a dark alley.

The contents of the .prj file (which seems to define the projection) are as follows:

GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROI
+D["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degr
+ee",0.017453292519943295]]
[download]

Here's the code I've slapped together:

#!/usr/local/bin/perl -w
use strict;
use Geo::ShapeFile;
use Geo::ShapeFile::Point comp_includes_m => 0, comp_includes_z => 0;
my $shapefile = new Geo::ShapeFile("/my/shape/dir/shape_group");

for(1 .. $shapefile->shapes()) {
  my $shape = $shapefile->get_shp_record($_);
  print "===============================================\n";
  print "ID: ", $shape->shape_id(), "\n";
  print "Centroid: ", $shape->centroid(), "\n";
  print "Parts: ", $shape->num_parts(), "\n";
  print "Points: ", $shape->num_points(), "\n";
  print "Type: ", $shape->shape_type(), "\n";
  print "X min: ", $shape->x_min(), "\n";
  print "Y min: ", $shape->y_min(), "\n";
  print "X max: ", $shape->x_max(), "\n";
  print "Y max: ", $shape->y_max(), "\n";
  print "Height: ", $shape->height(), "\n";
  print "Width: ", $shape->width(), "\n";
  my @points = $shape->corners();
  foreach my $this_corner (@points) {
    print "Corner X: ", $this_corner->X(), "\n";
    print "Corner Y: ", $this_corner->Y(), "\n";
  }
  print "===============================================\n";
}
[download]

... and here's the output:

===============================================
ID: 1
Centroid: Point(X=-1.36971256117202e+301,Y=5.19769721893395e+296)
Parts: 1
Points: 189
Type: 5
X min: 3.99649220734208e-297
Y min: -6.04919389741984e-286
X max: 5.7228212357179e-306
Y max: 1.59100403324442e+218
Height: -3.99649220161926e-297
Width: 1.59100403324442e+218
Corner X: 3.99649220734208e-297
Corner Y: -6.04919389741984e-286
Corner X: 5.7228212357179e-306
Corner Y: -6.04919389741984e-286
Corner X: 5.7228212357179e-306
Corner Y: 1.59100403324442e+218
Corner X: 3.99649220734208e-297
Corner Y: 1.59100403324442e+218
===============================================
[download]

I'm using version 2.51 of Geo::ShapeFile. Any insight that the monks can provide would be very much appreciated.

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