[OSM-talk] Preview: national cycle network map

Andy Allan gravitystorm at gmail.com
Thu Jul 19 11:47:12 BST 2007


On 7/19/07, Steve Chilton <S.L.Chilton at mdx.ac.uk> wrote:
> Andy
>
> Couple of further thoughts.
>
> I would think that best order would be :
> 1 "non-involved" detail - all the background stuff
> 2 red/blue emphasis lines for NCN - which will show around layer 3
> 3 way detail that it is on - road, bridleway, cycleway etc
> 4 NCN ref numbers
> NB: there are some inconsistencies z-values at present. Look where route 4 comes into NE of Richmond Park (can't do URL to it)

permalinks is on the todo :-)

>first (unclassified?) road is above and when swings south the road
(service?) is below.

That's actually because the route to the NE is on a cycleway adjacent
to the road, and the existing z-order in the main mapnik layer paints
that below the road. But I take your point.

>
> There are artefacts where "sections" of red/blue butt up, which multiply in sections are very short. Is this because of transparency?

Yeah, mapnik appears to paint each line one at a time, so partially
transparent ways are additive when they overlap. I don't know if
mapnik is able to apply the transparency per matched-feature instead
of per-stroke. It's something I was trying to get rid of. Maybe
there's another way to do the same thing, but I can't find any mapnik
documentation!

Cheers,
Andy


>Can you look at that? At first I thought they had some special
significance. In my view it detracts from smooth visualising of the
routes.

> I like Blackadder's suggestion for bringing up non-ncn cycle specific stuff - change emphasis in mapnik style sheet? But beware of coalescing data.
>
> Maybe Artem could answer directly on shield/shift issues.
>
> With a bit of tweaking I will be asking permission to use this as an exemplar of use of OSM data at SoC conf in September.
>
> Cheers
> STEVE
>
>         -----Original Message-----
>         From: Andy Allan [mailto:gravitystorm at gmail.com]
>         Sent: Thu 19/07/2007 11:00
>         To: Steve Chilton
>         Cc: OSM-Talk
>         Subject: Re: [OSM-talk] Preview: national cycle network map
>
>
>
>         On 7/19/07, Steve Chilton <S.L.Chilton at mdx.ac.uk> wrote:
>         > Andy
>         >
>         > Initial thought is that it looks excellent.
>         > Two suggestions spring to mind having zoomed through layers in to Richmond:
>         > Can you make the blue and red overlays more transparent? It would be good to see more clearly what the underlying way type is - road, bridleway, footway, etc.
>
>         There's a couple of z-index issues I need to look at - roads are
>         rendered over cycleways at the moment, so when they are adjacent it
>         looks misleading. I'm considering trying to make the tagged ways
>         render in front of the highlighting, and the highlighting above the
>         non-involved ways, so that the underlying type is more obvious.
>
>         > Secondly can you somehow filter the number of occurences of the NCN number? In Richmond Park it is obviously number 4 at all times and doesn't need all those labels.
>
>         Yeah, that's the mapnik shieldsymbolizer "minimum radius" thing I had
>         asked about previously on the lists (for the coloured boxes). It's
>         apparently in a the head version of mapnik but I haven't got that
>         running yet.
>
>         I'd also tried shifting the in-line numbers at high zoom to the side
>         of the route (since the higher the zoom, the less you want the route
>         overwritten), but I couldn't make dy="80" work on the textsymbolizer.
>         Works fine for point names (e.g. pubs) but I couldn't make it work
>         when writing on the lines.
>
>
>         > Otherwise really encouraging. Good work.
>
>         Thanks.
>
>         Andy
>
>         >
>         > Cheers
>         > STEVE
>         >
>         >         -----Original Message-----
>         >         From: talk-bounces at openstreetmap.org on behalf of Andy Allan
>         >         Sent: Thu 19/07/2007 10:23
>         >         To: OSM-Talk
>         >         Cc:
>         >         Subject: [OSM-talk] Preview: national cycle network map
>         >
>         >
>         >
>         >         Hi All,
>         >
>         >         I'll call it a preview, since there's still more on my Todo list than
>         >         on the Done list!
>         >
>         >         http://www.gravitystorm.co.uk/osm/  - a mapnik-based cycle layer
>         >
>         >         Shows the UK national cycle network, and local cycle networks at
>         >         higher zoom. Have a look at Putney, south west of central london, for
>         >         an area with both national and local (London) cycle networks.
>         >
>         >         I'm very interested in feedback, and I've got more plans to render
>         >         more features and play with the rendering, but I thought I'd "release
>         >         early" etc. I'm also keen to know if there are similar cycle networks
>         >         in the osm database for other parts of the world - if you know of
>         >         them, please let me know where they are and I'll look at rendering
>         >         them too.
>         >
>         >         Feedback appreciated, positive or negative.
>         >
>         >         Cheers,
>         >         Andy
>         >
>         >         PS - This takes about 5 hours to render on a modest PC, and other hour
>         >         to transfer to my new web host. I'd strongly recommend people play
>         >         more with Mapnik than trying to set up the entire tiles-at-home kind
>         >         of thing, since the physical infrastructure required by mapnik is
>         >         much, much less.
>         >
>         >         PPS - Thanks go to Dave Stubbs (randomjunk) for his help with this.
>         >
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>         >
>         >
>         >
>
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