...
for distance, always have at least 2 numbers NOTE: this method implies a higher level of accuracy within the data. For example: "a half mile" suggests that the collector was making a guess, whereas 0.5 miles seems more precise. You can use "ca. 0.5 mi" if you wish to suggest less precision. This standard is recommended only in that it keeps the data tidy (fewer duplicates) and easy to read. It may not be the best solution for other museum collections.
1.0 mi = 1 mile
0.5 mi = 1/2 mile. Do not use ".5"
12 mi = 12 miles. You don't need a decimal if you have at least two numbers
...