[postgis-devel] Proposal: Adding buffer parameter to ST_TileEnvelope()

[Yuri Astrakhan]

I am thinking of the percentage in terms of linear bounding box side shift
in the outwards direction, so buffer=0.5 would make each side shift
outwards by half a tile size, thus producing a box 2x2 of the original tile
== 4x increase in the tile area.  Buffer might be a bad word for this
parameter?

On Wed, Nov 13, 2019 at 1:04 PM <rmrodriguez at carto.com> wrote:

> On Wed, Nov 13, 2019 at 6:44 PM Yuri Astrakhan <yuriastrakhan at gmail.com>
> wrote:
> >
> > Michael, thank you for your example. Per Paul's previous email, it made
> me realize that unlike ST_AsMVTGeom, ST_TileEnvelope does not need to
> understand the concept of extent (internal "pixels"), but instead can work
> just as well with percentages.
> >
> > Updated proposal:   buffer is a percentage increase of the original
> tile, limited to SRID space.  E.g.  buffer=0.5 would grow the tile by 50%,
> but if zoom=0, it would not grow at all.  If the tile is on the edge (e.g.
> 0,0), growing it should extend the longitude across the anti-meridian line,
> but should not grow northwards (srid limit).
>
>
> Would that be 0.5x bigger area or 50% bigger sides, thus being 1.25x
> bigger area?
>
>
> --
> Raúl Marín Rodríguez
> carto.com
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