[postgis-tickets] [PostGIS] #3712: Address MVT issues reported by specification author

[PostGIS]

#3712: Address MVT issues reported by specification author
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  Reporter:  strk     |      Owner:  Björn Harrtell
      Type:  defect   |     Status:  new
  Priority:  blocker  |  Milestone:  PostGIS 2.4.0
 Component:  postgis  |    Version:  trunk
Resolution:           |   Keywords:
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Comment (by Björn Harrtell):

 I'm now leaning towards both suggestions by @flippmoke and @strk i.e
 providing a function that generates spec compliant output if not forced
 otherwise and breaking apart the logic assembling the tile binary vs. the
 geometry translation. I propose the following revised ST_AsMVT and a new
 function ST_AsMVTGeom as follows:

 {{{#!sql
 -- revised ST_AsMVT function
 -- assumes geometry already in MVT tile coordinate space
 -- moved bounds, buffer and clip_geom to new function ST_AsMVTGeom
 bytea ST_AsMVT(text name, integer extent, text geom_name, anyelement row)

 -- translates a geometry to MVT tile coordinate space with optional
 clipping
 -- should make sure output is valid according to spec, perhaps by simply
 using existing ST_MakeValid logic
 geometry ST_AsMVTGeom(geometry geom, box2d bounds, integer extent, integer
 buffer, boolean clip_geom)
 }}}

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Ticket URL: <https://trac.osgeo.org/postgis/ticket/3712#comment:22>
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