[SIS-542] Mercator auxiliary sphere

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2
• Component/s: Referencing
• Assignee: Martin Desruisseaux
• Reporter: Martin Desruisseaux
• Created: 21/Apr/22 12:42
• Updated: 07/Dec/22 18:33
• Resolved: 28/Apr/22 09:10

Description

This operation method is defined by ESRI:

https://desktop.arcgis.com/en/arcmap/latest/map/projections/mercator.htm

Of particular interest the meaning of "Auxiliary Sphere Type" parameter:

• 0 = use semimajor axis or radius of the geographic coordinate system
• 1 = use semiminor axis or radius
• 2 = calculate and use authalic radius
• 3 = use authalic radius and convert geodetic latitudes to authalic latitudes

Types 0 to 2 are easy, type 3 is more tricky and may not be supported in the first version. Type 0 is equivalent to "Popular Visualisation Pseudo Mercator" projection method.