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https://issues.apache.org/jira/browse/SIS-369?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Desruisseaux updated SIS-369:
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Fix Version/s: (was: 1.1)
1.2
Affects Version/s: 1.1
1.0
> Better selection of datum shift method depending on desired accuracy
> --------------------------------------------------------------------
>
> Key: SIS-369
> URL: https://issues.apache.org/jira/browse/SIS-369
> Project: Spatial Information Systems
> Issue Type: Improvement
> Components: Referencing
> Affects Versions: 0.8, 1.0, 1.1
> Reporter: Martin Desruisseaux
> Priority: Minor
> Fix For: 1.2
>
>
> Coordinate operations may be slow, especially when datum shifts are involved.
> When not using datum shift grid files, the most common method is _geocentric
> translation_. The _Molodensky_ method is a little bit faster at the expanse
> of accuracy, but that accuracy lost may be acceptable for example if the
> scale on a map is not sufficient for seeing the difference. At very small
> scale where each pixel is 10 km wide, we can even skip the datum shift
> operation completely. The question is where to put the threshold. 5 meters
> for _Molodensky_, 10 meters for _Abridged Molodensky_, 3 km for none? This
> need to be measured, for example by trying all _geocentric translation_
> operations in the EPSG database. Once thresholds have been determined, the
> {{DatumShiftMethod.forAccuracy(double)}} method should be updated accordingly.
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