Hello Tony, I import the standard processed_p.shp coastlines shapefile (available from the OSM github repository IIRC) and import that into the postgis database using shp2pgsql (standard command line tool). This creates a series of *land* polygons in the database - squares inland and multi-point on the coast.
The GeoJSON generated from the database therefore contains land polygons (tagged with "natural=land"). These are styled using an off-white colour. The background colour of the map is blue (sea): land polygons are drawn on top of this background. Nick -----tony wroblewski <tony.wroblew...@gmail.com> wrote: ----- To: Nick Whitelegg <nick.whitel...@solent.ac.uk> From: tony wroblewski <tony.wroblew...@gmail.com> Date: 12/12/2013 06:26PM Cc: Neil Pilgrim <osm-talk...@kepier.clara.net>, talk-gb@openstreetmap.org Subject: Re: [Talk-GB] Freemap - experimentally expanding to cover the whole of England HI Nick, Quick question. How are you dealing with rendering the coastline? Tony On 12 December 2013 13:59, Nick Whitelegg <nick.whitel...@solent.ac.uk> wrote: Hello Neil, Normally it updates every week. This latest update was a whole England planet file taken from geofabrik on Monday or Tuesday (can't remember exactly which day) so should be up to date up to the weekend, certainly in your area which wasn't covered before this latest import. Yes, it could be possible to render surrounding tiles, or at least schedule a cron job to run popularly requested areas in the background at quiet times of day e.g. between 0100-0600 (given this is a UK only site we can probably assume this will be quiet). The blue artefacts are a bug. There were a few issues I never got round to resolving when I originally implemented the client side renderer. What I intend to do is go back to the original Python server side code examples provided by the kothic developers and see if I can work out what's missing/different in my code. This should hopefully improve performance as well. If you now search for Wivenhoe it should appear near instantaneously. Nick -----Neil Pilgrim <osm-talk...@kepier.clara.net> wrote: ----- From: Neil Pilgrim <osm-talk...@kepier.clara.net> Date: 12/12/2013 12:37PM Cc: "Talk-GB@openstreetmap.org" <talk-gb@openstreetmap.org> Subject: Re: [Talk-GB] Freemap - experimentally expanding to cover the whole of England I've confirmed that it renders fine around Wivenhoe/Alresford, but is a bit slow as you say. I do appreciate being able to tell the rights of way from normal footpaths etc (though there is no legend?). Few questions: - I know this is an expansion, but how often does it update? (I've added some paths/RoW quite recently and they've not appeared yet) - Is it feasible to start rendering surrounding tiles "just in case", once the current one(s) are done? - There appear to be blue horizontal/vertical lines on the map; are these artifacts of the rendering or intentional? They can look a bit like water here, especially near coastlines where there may already be ditches, etc nearby. Note that I've not played with the features other than the base map yet. Cheers, -- Neil On 12 December 2013 00:34, Nick Whitelegg <nick.whitel...@solent.ac.uk> wrote: > Hi, > > Before relying on any third-party resources I'm experimenting with expanding > Freemap (www.free-map.org.uk)'s coverage to the whole of England (will > probably be Wales too next week) on my own server. > > This is now live. It does mean that first time a given map tile is rendered > (map tiles are GeoJSON-like and rendered by kothic-js, http://kothic.org) it > will be _slow_ - perhaps 30+ seconds. I will try and optimise the backend > sql queries by examining the native kothic python server-side code. > However, the data is then cached meaning that next time you visit the area > it will be much faster. > > Freemap's web services (see > http://www.free-map.org.uk/0.6/about.html#developer) do not seem to be > impacted so strongly (in terms of a slowdown) as the renderer suggesting the > rate determining step is somewhere in the rendering process. > > However I suspect both the renderer and web services will be very slow in > London due to sheer volume of data. But TBH both the site and web services > are more aimed at countryside use so I'm not too fussed by that. > > Nick > > _______________________________________________ > Talk-GB mailing list > Talk-GB@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk-gb > _______________________________________________ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb _______________________________________________ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
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