Hi Silvana:

Based on your numbers, the scale is (in inches or in centimeter) *1:142,560*

The scale expresses the distance on the map in relation to the distance on
the ground. The number that counts is what you measure on the map, although
some maps reports the fraction or ratio of it. Independently from the unit
measure (inches or centimeters) one number should be always 1 is the
denominator of the fraction is reporting the

Your scale either is given in English miles and inches (so, 1 inch = 2.25
miles or 142,560 inches since there are 63,360 inches in 1 mile) or in
metric units (so, 1 cm = 142,560 cm)

You cannot give 1 inch in metric (you need to do a conversion like the one
I did below).
The number 57217 is close --but clearly not the same -- as one divides
142,560 by 2,54 (equivalent to 1 inch, but in centimeter). However, it is
wrong.

Here is the equation:
x_inches= 2.25 mi/in * 63360 in/1mi = *142,560*
x_cm= 2.25 mi/cm * 160934.4 cm/mi / 1 in/cm * 2.54 cm/in = *142,560*

This is my calculation -- on the back of an envelope -- with your numbers.

Good luck.

Lucia

On Tue, Jun 13, 2017 at 11:52 AM, <[log in to unmask]> wrote:

> 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
>
>