On 05/04/2012 06:13 PM, Thomas Davie wrote: > A simple method of fixing this might be to introduce a new property > to the canvas element – projection. > > Different projections would then pay attention to different zoom > condition formats; e.g. if projection:merkator was specified, |z0-... > would be expected; while if projection: OSGrid or projection: > spherical were used, then |s25000 might be expected.
Hi Bob, style authors should have the choice between |z... and |s..., it's too much redundancy to specify both. In addition, I don't like the idea of fixing the projection for a given style. There is no reason, why a style shouldn't work for all kinds of projections. Paul > On 4 May 2012, at 17:03, Paul Hartmann wrote: > >> On 05/01/2012 03:59 PM, Richard Fairhurst wrote: >>> On 01/05/2012 14:47, Paul Hartmann wrote: >>>> In my opinion, it should be the same in MapCSS and the >>>> definition of the zoom selector should be based on map scale >>>> rather than on the projected coordinates in the Mercator >>>> projection. >>> >>> My long-term intention for the zoom selector was that "z" would >>> not be the only way of specifying a zoom level, but that we could >>> also have "s" for a standard ratio scale. >>> >>> So: >>> >>> |z14-18 # "900913" zooms 14-18 |s25000-50000 # 1:25k to >>> 1:50k >> >> For a map that is displayed on screen, a scale such as 1:50k is >> not enough, because you usually don't know the monitor resolution. >> >> We could either use a scale in cm/px directly, or assume some >> arbitrary pixel size, like 0.28 mm. >> >>> I think we absolutely need to keep the z selector as it is. >>> Otherwise, there is no way to work out what features to include >>> in a simplified database for small-scale rendering, bearing in >>> mind that 900913 maps represent 90% of the webmaps in use today. >>> But offering an alternative for those who want it makes sense to >>> me. >> >> I see that this simplicity is desirable for a TMS using 900913 >> (aka EPSG:3857). >> >> But it gets problematic when the map is based on a different >> projection. Are you supposed to replicate the 900913 distortions? >> This is hard to swallow. >> >> Paul >> >> _______________________________________________ Mapcss mailing >> list [email protected] >> http://lists.openstreetmap.org/listinfo/mapcss > > > > > _______________________________________________ Mapcss mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/mapcss _______________________________________________ Mapcss mailing list [email protected] http://lists.openstreetmap.org/listinfo/mapcss
