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Posted to commits@sis.apache.org by "Martin Desruisseaux (JIRA)" <ji...@apache.org> on 2017/11/17 14:22:00 UTC

[jira] [Closed] (SIS-260) Geographic 3D to 2D conversions (EPSG:9659)

     [ https://issues.apache.org/jira/browse/SIS-260?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Martin Desruisseaux closed SIS-260.
-----------------------------------

> Geographic 3D to 2D conversions (EPSG:9659)
> -------------------------------------------
>
>                 Key: SIS-260
>                 URL: https://issues.apache.org/jira/browse/SIS-260
>             Project: Spatial Information Systems
>          Issue Type: Sub-task
>          Components: Referencing
>            Reporter: Martin Desruisseaux
>            Assignee: Martin Desruisseaux
>            Priority: Minor
>             Fix For: 0.7
>
>
> The forward case (3D to 2D) is trivial: just drop the height. The reverse conversion however is in principle undefined, but in practice often needed. The "less bad" approach would be to take a mean-sea level of 0, which is uneasy to convert to ellipsoidal height. See §2.2.4 in IOGP Publication 373-7-2 – Geomatics Guidance Note number 7, part 2 – April 2015.



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