Matrix directionality


Matrix currently matches and compares points, regardless of the direction of the track. Using points A, B and C to indicate points, and using 1 or 2 to indicate the frequency of reaching those points on an out-and-back route or other routes where a different path is taken to get to each point, the problem that exists is that Matrix has no way to differentiate between an A1-B1 pairing and a A1-B2 pairing on an out-and-back course. In contrast, the Trails plugin has this directionality but is unable to compare tracks across different activities. Recommend that either there is a separate category for each point combination, or simply the return pairings (A1-B2, A1-A2, C1-B2, C1-A2) are ignored. The latter might be accomplished by filtering all points after the terminus point in Trails. The ToolTip subset in the attached file illustrates the issue; the approximate A1-B1 distance is 2.6 miles and the approximate A1-B2 distance is 5.4 miles, yet both are included in the A-B pairing.

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gerhardo wrote Aug 24, 2010 at 6:48 PM

The core engine in Matrix is to handle single points. It is hard to accomplish directionality in the detection engine inMatrix.
The latest update can detect a point more than once (when the track is "enough" away from the first point, it starts to look for better matches, but the core is still handling point to point.
I rather keep it this way actually and add direction handling etc in something like Trails (that would need multi activity handling), but Trails are handling Trails: A set of points that must be visited in a certain order.

Some filtering/pruning on the results can be done though:
  • Requiring all points to be matched (without requiring order).
  • Prune results so only first match is included (so only A1-B1 is visible in the example).

wrote Feb 13, 2013 at 3:36 AM