The ordering of lat/lon is not the only tricky part of working with geographic coordinates, sadly. "Between" the pair of numbers and a real point location on ea

The ordering of lat/lon is not the only tricky part of working with geographic coordinates, sadly. "Between" the pair of numbers and a real point location on earth, there are two levels of abstraction used in the definitions of latitude and longitude: 1. physical surface is modeled by a geoid, a surface which approximates the mean sea level over the oceans and its continuation under the land masses. 2. The geoid is approximated by a reference surface, a geometric shape simpler to describe (in closed form, with few parameters). For example, an ellispoid like WGS84 (the "84" is the year of the introduction of this standard) is commonly used. Furthermore there is the distinction between "geodetic" latitude ϕ (without qualification): the angle between the normal and the equatorial plane - this should be given with a specification of the ellipsoid and "geocentric" or "spherical" latitude θ (or ψ, q, ϕ′, ϕc, ϕg): the angle between the radius and the equatorial plane. (Figure below). Quoting from https://en.wikipedia.org/wiki/Latitude https://en.wikipedia.org/wiki/Latitude : "The importance of specifying the reference datum may be illustrated by a simple example. On the reference ellipsoid for WGS84, the centre of the Eiffel Tower has a geodetic latitude of 48° 51′ 29″ N, or 48.8583° N and longitude of 2° 17′ 40″ E or 2.2944°E. The same coordinates on the datum ED50 define a point on the ground which is 140 metres (460 feet) distant from the tower.[citation needed] A web search may produce several different values for the latitude of the tower; the reference ellipsoid is rarely specified." Whereas confusing lat/lon order usually is noticed as a bug because some points end up in an ocean or close to the poles, use of the wrong datum (reference surface) leads to more subtle errors (as the above example shows) and is therefore more likely to go undetected. What I recommend is to use test cases with well-known points and check in your GIS processing pipelines that a few test locations are still where you expect them to be at certain check points in your process.