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https://issues.apache.org/jira/browse/SIS-49?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13408364#comment-13408364
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Ross Laidlaw edited comment on SIS-49 at 7/6/12 10:46 PM:
----------------------------------------------------------
I've modified the loop and surrounding code as shown below to make it a bit
easier to read and to prevent the ArrayIndexOutOfBoundsException:
{code}
LatLon[] points = new LatLon[numberOfPoints + 1];
double bearingIncrement = 0;
if (numberOfPoints > 0) { bearingIncrement = 360/numberOfPoints; }
for (int i = 0; i < numberOfPoints; i++)
{
points[i] = DistanceUtils.getPointOnGreatCircle(this.center.getLat(),
this.center.getLon(), radius, i * bearingIncrement);
}
points[numberOfPoints] = points[0];
{code}
was (Author: rlaidlaw):
I've modified the loop and surrounding code as shown below to make it a bit
easier to read and to prevent the ArrayIndexOutOfBoundsException:
{code}
LatLon[] points = new LatLon[numberOfPoints + 1];
int bearingIncrement = 360/numberOfPoints;
for (int i = 0; i < numberOfPoints; i++)
{
points[i] = DistanceUtils.getPointOnGreatCircle(this.center.getLat(),
this.center.getLon(), radius, i * bearingIncrement);
}
points[numberOfPoints] = points[0];
{code}
> ArrayIndexOutOfBoundsException caused by method
> getCircularRegionApproximation(int numberOfPoints) in LatLonPointRadius class
> -----------------------------------------------------------------------------------------------------------------------------
>
> Key: SIS-49
> URL: https://issues.apache.org/jira/browse/SIS-49
> Project: Spatial Information Systems
> Issue Type: Bug
> Components: geometry objects
> Reporter: Ross Laidlaw
> Assignee: Ross Laidlaw
> Priority: Minor
> Labels: gsoc2012
> Fix For: 0.3-incubating
>
> Attachments: SIS-49.rlaidlaw.2012-07-06.patch.txt
>
>
> The method public LatLon[] getCircularRegionApproximation(int numberOfPoints)
> throws an ArrayIndexOutOfBoundsException under certain conditions. This is
> because of an error in the following loop:
> {code}
> LatLon[] points = new LatLon[numberOfPoints + 1];
> for (int i = 0; i < 360; i += (360 / numberOfPoints))
> {
> points[i] = DistanceUtils.getPointOnGreatCircle(this.center.getLat(),
> this.center.getLon(), radius, i);
> }
> {code}
> The exception arises because integer i is used as the array index for the
> points array, but the value of i jumps up by (360/numberOfPoints) on every
> iteration of the loop. For example, if numberOfPoints is 10, then i will
> increase by 36 each time, resulting in the exception. The points array size
> is set before the loop to 'numberOfPoints + 1'.
> As an experiment, I changed the loop as shown below and this appeared to fix
> the problem. There may be a more elegant solution:
> {code}
> LatLon[] points = new LatLon[numberOfPoints + 1];
> for (int i = 0, j = 0; i < 360; i += (360 / numberOfPoints), j++)
> {
> points[j] = DistanceUtils.getPointOnGreatCircle(this.center.getLat(),
> this.center.getLon(), radius, i);
> }
> {code}
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