GeoMarketing filters within Adobe Campaign instance. When performing a distance calculation, it appears that the distance measurement is calculated in kilometers as opposed to miles. Does Adobe Campaign uses imperial or metric calculations on their backend for the product?
Distance calculation formula used at backend is 'Law of Cosines'.
distance= acos( sin φ1 ⋅ sin φ2 + cos φ1 ⋅ cos φ2 ⋅ cos Δλ ) ⋅ R
where φ1= second parameter
φ2= fourth parameter
Δλ= differeence of first parameter and third parameter.
R = 6371
And output of this calculation will be in kilometers.
Its by default in Kilometer, if you want to use it in Miles then Distance (@LongitudeA, @LatitudeA, @LongitudeB, @LatitudeB)*0.6213712 to be precise. We have implemented this on a recent project.
Disclaimer: Please don't expect it to be a logical distance measured by Google Map etc, because its total based on the mathematical calculation. In the back-end Adobe uses the below formula :