Linear referencing in the context of Curvilinear coordinate

Geopositioning is the process of determining or estimating the geographic position of an object or a person.Geopositioning yields a set of geographic coordinates (such as latitude and longitude) in a given map datum. Geographic positions may also be expressed indirectly, as a distance in linear referencing or as a bearing and range from a known landmark.The resulting geoposition is sometimes referred to as geolocation, and the process of geopositioning may also be described as geo-localization.In turn, positions can be used to determine a more easily understandable location, such as a street address (see reverse geocoding).

A milestone is a numbered marker placed on a route such as a road, railway line, canal or boundary. They can indicate the distance to towns, cities, and other places or landmarks like mileage signs; or they can give their position on the route relative to some datum location (a zero milepost). On roads they are typically located at the side or in a median or central reservation. They are alternatively known as mile markers (sometimes abbreviated MMs), mileposts or mile posts (sometimes abbreviated MPs). A "kilometric point" is a term used in metricated areas, where distances are commonly measured in kilometres instead of miles. "Distance marker" is a generic unit-agnostic term.