On Sunday 24 July 2016, Rory McCann wrote: > > The problem (correct me if I'm wrong!) is that with vector tiles it's > common to generate them only down to a certain zoom level (e.g. z14), > and for lower zoom levels (z15+) to use the z14 tile, and just crop > out the area you want, i.e. you are using the result of z14 SQL > queries for z15+. > > The SQL queries are run when generating the .pbf vector tiles, and > only go down to z14. For generating images, SQL isn't run and instead > have to use the pregenerated pbf, and hence pregenerated way_pixels > value. Hence you have to change the style, not the SQL. > > If you don't change it, areas that should appear at z15+ won't, since > the way_pixels will be wrong for that zoom.
Ok - so you essentially say that use of !pixel_width! and !pixel_height! is - in the vector tiles system used - limited to the lower zoom levels. That however would also mean you would need to remove all the way_area > 0.01*!pixel_width!::real*!pixel_height!::real filters from SQL for z14 - otherwise you get missing geometries at the higher zooms (not a real lot - that limit is about one Mercator square meter at z14 - but when this occurs it would be visible and possibly surprising). And if i understand you correctly this also means you cannot render any features differently on z14 and any higher zoom level based on processing done in SQL - unless you duplicate them into different separate layers for different zoom levels. -- Christoph Hormann http://www.imagico.de/ _______________________________________________ dev mailing list [email protected] https://lists.openstreetmap.org/listinfo/dev
