sis-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Peter Karich (JIRA)" <j...@apache.org>
Subject [jira] [Created] (SIS-51) Pluggable Distance Calculation
Date Mon, 16 Jul 2012 12:50:34 GMT
Peter Karich created SIS-51:
-------------------------------

             Summary: Pluggable Distance Calculation
                 Key: SIS-51
                 URL: https://issues.apache.org/jira/browse/SIS-51
             Project: Spatial Information Systems
          Issue Type: Improvement
            Reporter: Peter Karich
            Priority: Minor


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 ...

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message