Calculation of Distance Represented by Degrees of Latitude and Longitude

Longitude (X axis value):

Length of 1 degree of Longitude = cosine (latitude) * length of degree (miles) at equator
1° Longitude = cos (33.1519) * 69.172 mi = 57.912 miles * 5280 feet · mile^-1 = 305,775 ft

we only want a fraction of the total 1 degree:

305,775 ft · 1° of longitude^-1 * 0.4292° longitude on map (difference between X minimum and maximum in Grid Info...) =
= 131,239 ft along bottom latitude

This is the X value = 131,239 ft

Latitude (Y axis value):

Degrees of Latitude vary from polar flattening, but only by 0.7 miles (1.13 km). Since this value is neglible, you can ignore the effects of flattening to obtain the length of 1 degree of latitude (http://www.ncgia.ucsb.edu/education/curricula/giscc/units/u014/u014_f.html).

for example:

length of 1° of latitude = 1° * 69.172 miles = 69.172 miles
69.172 miles * 5280 ft · mile^-1 = 365, 228 ft · 1° of latitude^-1
365,228 ft · 1° of latitude^-1 * 0.2112° of latitude on map (difference between Y min. and max. in Grid Info...) =
= 77,136 ft This the Y value = 77,136 ft