Method, apparatus, and system for providing a signed angle metric for mapmatching based on probe data

An apparatus comprising:

• at least one processor;
• and
• at least one memory including computer program code for one or more programs,
• the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following,
• process probe data collected from a probe device to determine a probe heading, wherein the probe heading indicates a direction of travel of the probe device;
• match the probe data to a road link;
• determine a link heading of the road link, wherein the link heading indicates a direction along which the road link is oriented;
• compute a magnitude of an h-value metric based on a difference between the probe heading and the link heading;
• determine a sign of the h-value metric based on a position of the probe heading relative to the link heading, wherein the sign is either a negative sign or a positive sign;
• and
• provide the h-value metric comprising a combination of the magnitude and the sign as an output.

A non-transitory computer-readable storage medium, carrying one or more sequences of one or more instructions which, when executed by one or more processors, cause an apparatus to at least perform the following steps:

• processing probe data collected from a probe device to determine a probe heading, wherein the probe heading indicates a direction of travel of the probe device;
• matching the probe data to a road link;
• determining a link heading of the road link, wherein the link heading indicates a direction along which the road link is oriented;
• computing a magnitude of an h-value metric based on a difference between the probe heading and the link heading;
• determining a sign of the h-value metric based on a position of the probe heading relative to the link heading, wherein the sign is either a negative sign or a positive sign;
• and
• providing the h-value metric comprising a combination of the magnitude and the sign as an output.