RFC 140 Errata

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RFC 140 Errata

Jackie Ng
Hi All,

In my original RFC 140 proposal, I wrote the following about the XYZ tile provider support.

>>> The "XYZ" provider implements tile rendering and access using the XYZ tiling scheme. Coordinate System is always LL84 ...

Upon further analysis, the statement about the LL84 coordinate system is false. The actual coordinate system that should be always used for XYZ tile sets is WGS84.PseudoMercator.

Using WGS84.PseudoMercator for XYZ tile sets produces more visually crisp tiles whereas LL84 tiles have noticeable visual distortions and blurriness. You can find a screenshot comparison of the XYZ tilesets under the two coordinate systems attached to the ticket below

http://trac.osgeo.org/mapguide/ticket/2550

Also included in that ticket is the patch to apply this change.

Are you comfortable with this change of coordinate system for XYZ tile sets? If the majority accepts this proposed change, it should be applied for all 3.0 milestone branches (both OS and adsk 2016 branches)

- Jackie
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Re: RFC 140 Errata

Jackie Ng
I'll take the silence as tacit approval for this change.

RFC 140 has been amended. The coordinate system for XYZ tile sets is now WGS84.PseudoMercator. I've also added an extra note about client application support for authoring XYZ tile sets should you be implementing a specialized tile set resource editor for your 2016 Infr. Studio release.

For consistency, please ensure that changesets 8581 and 8582 from trunk have been applied for your "3.0" adsk branch.

- Jackie