I was troubleshooting a complaint of missing postal code area geometries from GeoAnalytics. I didn't previously realize this, but not all postal codes (in the USA) have areas. Some examples: 77001, 77052, 77202, 77203:
These postal codes are in the GeoAnalytics location database for point geometry (they have center point coordinates)
![postal 1.png](/legacyfs/online/217135_postal 1.png)
But they are not in the GeoAnalytics location database for area geometry.
As you can see, 77001 has no area:
http://maps.huge.info/zip.htm
![postal 2.png](/legacyfs/online/217136_postal 2.png)
I didn't realize this, so I hope this helps someone.