Martin Desruisseaux created SIS-486:
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Summary: Some map projections produce wrong results when |Δλ| > 180°
Key: SIS-486
URL: https://issues.apache.org/jira/browse/SIS-486
Project: Spatial Information Systems
Issue Type: Task
Components: Referencing
Affects Versions: 1.0, 0.8
Reporter: Martin Desruisseaux
Assignee: Martin Desruisseaux
Fix For: 1.1
Some map projections produce a wrong result when the difference Δλ between the longitude value and the central meridian is greater than 180°. For most map projections there is no problem because the Δλ value is used directly in trigonometric functions which perform automatically the range reduction for us. For example sin(200°) = sin(-160°). However there is a few map projections where the longitude value is transformed (e.g. multiplied by some factor) _before_ to be given to a trigonometric function. For such map projections, we must apply the range reduction ourselves.
Impacted map projection methods in Apache SIS 1.0 are:
* Albers Equal Area (EPSG::9822)
* Lambert Conic Conformal (EPSG::9801, 9802, 9803, 9826, 1051)
* Oblique Stereographic (EPSG::9809)
* Satellite-Tracking projection
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