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https://issues.apache.org/jira/browse/SIS-145?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16482597#comment-16482597
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Martin Desruisseaux commented on SIS-145:
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ESRI is now publishing a list of their datum, together with other sources:
https://github.com/Esri/projection-engine-db-doc/blob/master/csv/pe_list_datum.csv
> Datum aliases for various producers
> -----------------------------------
>
> Key: SIS-145
> URL: https://issues.apache.org/jira/browse/SIS-145
> Project: Spatial Information Systems
> Issue Type: Improvement
> Components: Referencing
> Reporter: Martin Desruisseaux
> Priority: Minor
>
> When comparing two geodetic datum for equality, the datum name needs to be
> also compared because it is the only way to differentiate two otherwise
> identical datum - comparing the ellipsoid axes is not sufficient. However,
> different producers format the datum in various ways:
> * EPSG uses human-readable texts (e.g. {{"St. Paul Island"}}).
> * Many other producers replace spaces and punctuation by underscores (e.g.
> {{"St_Paul_Island"}}).
> * ESRI adds a {{"D_"}} prefix in front of datum names (e.g.
> {{"D_St_Paul_Island"}}.
> * In some rare occasions, some producers may use completely different names.
> We need to be able to detect when two datum are the same despite some
> variations in their names. In GeoTools, datum aliases were specified in a CSV
> file named {{DatumAliasesTable.csv}}. We can not port this file to Apache SIS
> for licensing reasons, and most of this port is not needed anyway. Applying
> the following rules during name comparisons is sufficient for the majority of
> cases:
> * Ignore upper/lower case.
> * Ignore any character which is not a letter or a digit.
> * Ignore the {{"D_"}} prefix
> However we still have the cases of completely different names or
> abbreviations. In many cases, the alternative name of abbreviation is in the
> EPSG database (e.g. {{"Nouvelle Triangulation Francaise"}} and {{"NTF"}}).
> But there is some remaining cases where the alternative name is not in the
> EPSG database neither. For example {{"Bogota 1975"}} is named {{"Bogota
> Observatory"}} by Oracle.
> We may need to identify which datum fail to be considered equivalent despite
> the above rules and EPSG aliases, and declare our own aliases for them.
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