[postgis-tickets] [PostGIS] #4744: St_AsMVT Errors on Some Polygons with Inner Rings

[PostGIS]

#4744: St_AsMVT Errors on Some Polygons with Inner Rings
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  Reporter:  reyemtm  |      Owner:  pramsey
      Type:  defect   |     Status:  new
  Priority:  medium   |  Milestone:  PostGIS 3.1.0
 Component:  postgis  |    Version:  3.0.x
Resolution:           |   Keywords:  vector tiles
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Comment (by Algunenano):

 I've done some more tests changing how big is the buffer around the tiles
 and it does indeed look like a stiching issue.

 Using a extent of 4096:
 - Buffer of 0: Lots of artifacts when stitching across tile boundaries.
 - Buffer of 4096/256 = 16 (the smallest one in CARTO): No artifacts at all
 - Buffer of 256 (Postgis Defaults): Ocasional artifacts (less than with
 buffer 0)

 Note that CartoVL by default uses extent / 256 as the buffer for
 historical reasons (from the time a tile was 256x256 pixels) but it could
 probably be smaller.

 Can you give a try to one of those services with a smaller extent and see
 if that makes your issues go away? They are changed in ST_AsMVTGeom and I
 from experience I would recommend it to be as small as possible (the
 extent / 256 seems to be working well for us).

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Ticket URL: <https://trac.osgeo.org/postgis/ticket/4744#comment:9>
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