The present invention provides systems and methods for improving the accuracy of location data, such as GPS data. In an embodiment, the present invention adjusts coordinates by receiving a sequence of coordinates corresponding to a plurality of locations; identifying in a map database, for each location, polyline features within a distance from the coordinates for the location; calculating emission probabilities for the polyline features; calculating transition probabilities for the polyline feature; and adjusting the coordinates for the plurality of locations so that the adjusted coordinates correspond to polyline features belonging to a sequence of polyline features selected, based on the emission probabilities and the transition probabilities, to be the most likely sequence of polyline features that correspond to the sequence of coordinates. Besides improving accuracy, embodiments of this invention enable novel geospatial applications and user interfaces by adding a large amount of meta-information to a location.