Scale is an expression of distance as a ratio in inches. Where 1 inch = 2.25 miles, you convert the miles into inches by multiplying 2.25 X 63,360 (the number of inches in 1 mile) to get the ratio in inches, which in this case multiplies out to 142,560, giving you 1:142,560. I was trained to measure the entire bar scale length in inches to the nearest 1/16 of an inch. In your case, 2.3 inches : the full length of the bar scale. You would multiply the bar scale length (miles) by 63,360 (inches) and divide both sides of your ratio by 2.3 to get your 1:? ratio. I only use the NSI when I have bar scale.



Leslie Wagner

Metadata Archivist

Access & Discovery

University of Texas at Arlington Libraries

817-272-6209

[log in to unmask] 





-----Original Message-----

From: Maps-L: Map Librarians, etc. [mailto:[log in to unmask]] On Behalf Of [log in to unmask]

Sent: Tuesday, June 13, 2017 10:53 AM

To: [log in to unmask]

Subject: scale cataloging question



Hello all,

I am a rare materials cataloger who occasionally does maps, and I struggle sometimes with determining scale. I am currently working on a

1868 map with a bar scale in English miles. I found a record that gives an approx. scale of 1:57,217, but I can't figure out how they came to that number. The bar scale measures approx 2.3 in, with 1 inch approx 2.25 English miles. When I compare 1 mile against the NSI I get a scale somewhere between 140,000-145,000, so I have no idea where the number 57217 comes from. I will try to attach some pics of the bar scale. Any help would be appreciated.

Thank you

-Silvana