A Decision-Rule Topological Map-Matching Algorithm with Multiple Spatial Data - Global Navigation Satellite Systems: Signal,Theory and Applications - page 227

Correct and incorrect snaps are computed before and after applying the map-matching
algorithm.

r

r

r

Fig. 10. Example of Three Consecutive GPS Data Points Considered False Negatives

Figure 11 presents the cases of snapped and not snapped data points before and after
applying the map-matching algorithm. The group of data points that does not snap to any
roadway contains either FN or points that have no solution. Data points that have roadway
centerlines within their buffers are either snapped correctly or incorrectly, or are FP. A data
point that snaps incorrectly before applying the algorithm and snaps correctly afterwards is

Fig. 11. Cases for Data Points Snapped and Not Snapped Before and After Applying the
Algorithm