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FAQ: How does an engineering scale relate to the scale in ArcMap?

Question

How does an engineering scale relate to the scale in ArcMap?

Answer

This question is most frequently related to files created in a Computer Aided Design (CAD) program.

An engineering scale, expressing scale as an inch on the map being equal to a number of feet or meters on the ground, must be converted to a proportional scale when the CAD data is to be used in ArcMap.

To convert the following engineering scale:

1" = 400' for use in ArcMap,

multiply the number of feet, in this case 400, by 12 to convert the feet to inches.

This yields a scale in ArcMap of 1:4800.

This is a proportional scale, in which the units on both sides of the colon (:) are the same.

1" = 4800"
1' = 4800'
1 meter = 4800 meters

If the engineering scale is expressed as

1" = 100 meters,

multiply the number of meters by 39.37, the number of inches in a meter. The proportional scale would then be:

1:3937