[SIS-51] Pluggable Distance Calculation

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Component/s: Referencing
• Assignee: Unassigned
• Reporter: Peter Karich
• Created: 16/Jul/12 12:49
• Updated: 16/Jul/19 14:02

Description

The distance calculation is done in several places. I think it shouldn't be a static helper method instead it should be an instance which could be replaced by a more precise or faster calculations:

double distance(double latFrom, double lonFrom, double latTo, double lonTo)

E.g. one could use euclidean distance, haversine calculation or a fast projection calulation (https://github.com/karussell/GraphHopper/blob/master/core/src/main/java/de/jetsli/graph/util/ApproxCalcDistance.java + see test).

Also one should think about "normed" distances. I mean, if one does not need the actual distance and rather needs to compare distances one could avoid parts of the distance calculation and make it faster. e.g.:

sqrt(deltaX*deltaX + deltaY*deltaY) then gets: deltaX*deltaX + deltaY*deltaY and the comparisons of distances are still correct if done for all distances (eg. in a quad-tree). This could be done with a separate normedDistance method or probably just the same and a different implementation? Not sure ...

Issue Links

• is depended upon by: SIS-385 Inaccurate formulas in DistanceUtils
• is related to: SIS-465 Referencing on celestial bodies with high flattening factor
• relates to: SIS-386 Replace DefaultEllipsoid.orthodromicDistance(…) method