[Mapguide-trac] [mapguide-trac] #2550: RFC 140 Errata

[MapGuide Open Source]

#2550: RFC 140 Errata
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   Reporter:  jng           |       Owner:  jng
       Type:  defect        |      Status:  new
   Priority:  low           |   Milestone:  3.0
  Component:  Tile Service  |     Version:     
   Severity:  trivial       |    Keywords:     
External_id:                |  
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 According to the original RFC 140, I wrote the following about the XYZ
 tile provider

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

 In further tests, this is proved to be incorrect. The actual Cooordinate
 System should actually always be WGS84.PseudoMercator

 Having a LL84 coordinate system for XYZ tile sets produces tiles with
 noticeable visual distortion, whereas tiles from XYZ tile sets with a
 WGS84.PseudoMercator coordinate system have more crisp visual fidelity.

 Attached is:
  * A visual comparison of two different XYZ tile sets in both LL84 and
 WGS84.PseudoMercator coordinate systems
  * A patch to set the correct coordinate system to WGS84.PseudoMercator
 instead of LL84

 From a client tooling perspective, tile sets should be working against the
 WGS84.PseudoMercator coordinate system instead of LL84 in terms of tile
 set extents being set and/or transformed.

-- 
Ticket URL: <http://trac.osgeo.org/mapguide/ticket/2550>
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