On Fri, Jul 29, 2011 at 11:56 AM, Richard Fairhurst <[email protected]>wrote:
> > Perhaps one day Maperitive might parse MapCSS > styles optionally, just as JOSM allows you to choose between MapCSS and its > own MapPaint styles? Once I (hopefully) extend Maperitive with Python bindings, I see no obstacles for someone (maybe even me) writing a MapCSS parser in Python and using those bindings to render the maps appropriately. > You are of course right that declarative CSS-type rules will be slower to > parse (though web browsers seem to manage it fairly quickly ;) ). But > computers get faster, and for some people simplicity and universality are > an > adequate trade-off for speed. I see no problem with MapCSS when you have all of the geo data pre-loaded into memory. But I do see a problem if you have a planet-size PostGIS database, for one simple reason - workflow: - In MapCSS I would have to go through the list of all geo elements and apply any matching MapCSS styling rules to produce a graphic element. - Maperitive goes through the list of all rules and finds any matching geo elements (using rule selectors) for each rule. Then for each matching geo element a series of commands is executed which produce one or more graphic elements. In a large database going through the list of all geo elements (even if bound-boxed) would be prohibitively expensive. It's true that computers get faster, but the planet.osm gets bigger, too :) Given that my doubtless-inefficient rules > engine works tolerably quickly on Adobe's dog-slow Flash Player for Mac, I > suspect one done by a proper programmer in a proper environment could be > "fast enough" for many people. > I agree... Back then I was hoping to create a system that would be easy to use/write but still powerful enough for DB-based rendering with all OSM idiosyncrasies. Now that I've abandoned those foolish dreams, my hope is to provide something for different kinds of users. Igor
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