Extent and Shapefiles

[Matthew Roberson]

First, let me just say I just started using MapServer this week and I
am sort of confused by all the different ways maps can be projected.

When i use ogrinfo, to determine the Extent of a shapefile(in this case
the zipcode boundries for the state of Missouri), how do I know what
units the values are in?

Is the minx value below -95.774704 meters, feet, or something else?
Or maybe the minx value is expressed in degrees, minutes, seconds. How
can I tell?

Below is what output from ogrinfo on the aforementioned shapefile.

Thanks,

Matt

[imac-dev03:WebServer/Documents/data] matthewr% ogrinfo -al -so
zt29_d00.shp zt29_d00
INFO: Open of `zt29_d00.shp'
using driver `ESRI Shapefile' successful.

Layer name: zt29_d00
Geometry: Polygon
Feature Count: 1341
Extent: (-95.774704, 35.995683) - (-89.098843, 40.613640)
Layer SRS WKT:
(unknown)
AREA: Real (20.5)
PERIMETER: Real (20.5)
ZT29_D00_: Integer (11.0)
ZT29_D00_I: Integer (11.0)
ZCTA: String (5.0)
NAME: String (90.0)
LSAD: String (2.0)
LSAD_TRANS: String (50.0)
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