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Posted to commits@sis.apache.org by "Peter Karich (JIRA)" <ji...@apache.org> on 2012/07/16 14:50:34 UTC
[jira] [Created] (SIS-51) Pluggable Distance Calculation
Peter Karich created SIS-51:
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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 ...
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[jira] [Updated] (SIS-51) Pluggable Distance Calculation
Posted by "Chris A. Mattmann (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/SIS-51?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris A. Mattmann updated SIS-51:
---------------------------------
Component/s: distance functions
> Pluggable Distance Calculation
> ------------------------------
>
> Key: SIS-51
> URL: https://issues.apache.org/jira/browse/SIS-51
> Project: Spatial Information Systems
> Issue Type: Improvement
> Components: distance functions
> Reporter: Peter Karich
> Priority: Minor
> Fix For: 0.3-incubating
>
> Original Estimate: 2h
> Remaining Estimate: 2h
>
> 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 ...
--
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[jira] [Updated] (SIS-51) Pluggable Distance Calculation
Posted by "Chris A. Mattmann (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/SIS-51?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris A. Mattmann updated SIS-51:
---------------------------------
Fix Version/s: 0.3-incubating
> Pluggable Distance Calculation
> ------------------------------
>
> Key: SIS-51
> URL: https://issues.apache.org/jira/browse/SIS-51
> Project: Spatial Information Systems
> Issue Type: Improvement
> Components: distance functions
> Reporter: Peter Karich
> Priority: Minor
> Fix For: 0.3-incubating
>
> Original Estimate: 2h
> Remaining Estimate: 2h
>
> 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 ...
--
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