A computer-implemented method of correlating sensed position data with terrestrial features, the sensed position data comprising sensed position points, the terrestrial features being located by terrestrial data, comprising: receiving the sensed position data from a position sensing system operatively associated with a moveable object; selecting a reduced set of snap point candidates from the terrestrial data based on a sensed position point, wherein said selecting further comprises: referencing a two-dimensional grid comprising a plurality of intersecting lines (96,98) that define vertices at intersection points of the intersecting lines (96, 98), the two-dimensional grid being defined by a coordinate system that corresponds to a coordinate system for locating the terrestrial features; identifying a vertex of the two-dimensional grid that is nearest to the sensed position point; defining a search area based on the identified vertex; selecting as a set of snap point candidates all snap points in the terrestrial data that are within the defined search area; and selecting as the reduced set of snap point candidates all snap point candidates in the set of snap point candidates that are within a predetermined distance from the sensed position point; choosing a best snap point candidate from among the reduced set of snap point candidates based on a plurality of predictive variables and corresponding weighting factors for each snap point candidate in the reduced set of snap point candidates; and snapping the sensed position point to the best snap point candidate to produce a snapped position point, wherein said selecting, said choosing, and said snapping are performed in substantially real time so that said method correlates the sensed position data from the moveable object with terrestrial features in substantially real time. receiving the sensed position data from a position sensing system operatively associated with a moveable object; selecting a reduced set of snap point candidates from the terrestrial data based on a sensed position point, wherein said selecting further comprises: referencing a two-dimensional grid comprising a plurality of intersecting lines (96,98) that define vertices at intersection points of the intersecting lines (96, 98), the two-dimensional grid being defined by a coordinate system that corresponds to a coordinate system for locating the terrestrial features; identifying a vertex of the two-dimensional grid that is nearest to the sensed position point; defining a search area based on the identified vertex; selecting as a set of snap point candidates all snap points in the terrestrial data that are within the defined search area; and selecting as the reduced set of snap point candidates all snap point candidates in the set of snap point candidates that are within a predetermined distance from the sensed position point; referencing a two-dimensional grid comprising a plurality of intersecting lines (96,98) that define vertices at intersection points of the intersecting lines (96, 98), the two-dimensional grid being defined by a coordinate system that corresponds to a coordinate system for locating the terrestrial features; identifying a vertex of the two-dimensional grid that is nearest to the sensed position point; defining a search area based on the identified vertex; selecting as a set of snap point candidates all snap points in the terrestrial data that are within the defined search area; and selecting as the reduced set of snap point candidates all snap point candidates in the set of snap point candidates that are within a predetermined distance from the sensed position point; choosing a best snap point candidate from among the reduced set of snap point candidates based on a plurality of predictive variables and corresponding weighting factors for each snap point candidate in the reduced set of snap point candidates; and snapping the sensed position point to the best snap point candidate to produce a snapped position point, wherein said selecting, said choosing, and said snapping are performed in substantially real time so that said method correlates the sensed position data from the moveable object with terrestrial features in substantially real time.