[Talk-gb-midanglia] mapnik style sheet

[Philip Howarth]

Steve,

I believe I've found the main problem. I didn't use a default.style sheet
with osm2pgsql.  (I didn't know I was supposed to.)

This has left the database without a number of columns for things like
'construction' (used to mark unfinished roads, I believe). Any mapnik Style
which refers to one of these missing columns, then fails silently. This is
further confused because mapnik may only look for these columns at certain
zoom levels - so the Style works at some zooms and not others.

So, I will go back and repopulate my database...

One minor snag - the ubuntu packaged osm2pgsql is V0.52 and I believe the
latest is actually V0.55.  Do you (or anyone) know if this will cause any
issue? (I don't think I can face learning how to compile the whole thing
from source. Not just yet, anyway.)

The default.style I have found is Rev 14703 at
http://trac.openstreetmap.org/browser/applications/utils/export/osm2pgsql/default.style
Which you checked in 2 weeks ago - so I'm hoping will be OK!

There is clearly an opportunity for a Ladybird book on rendering - the
barriers to getting started seem very high to non software gurus like me!

Regards,

    Philip

2009/5/8 Steve Chilton <S.L.Chilton at mdx.ac.uk>

>  Philip
>
>
>
> Have you had any luck with sorting things out?
>
> I maintain the mapnik stylesheet that is used by the main site, which is
> the one that you seem to have picked from SVN.
>
> It would help to see examples of things that are not right if possible.
>
>
>
> Cheers
>
> STEVE
>
>
>
>
>  ------------------------------
>
> *From:* talk-gb-midanglia-bounces at openstreetmap.org [mailto:
> talk-gb-midanglia-bounces at openstreetmap.org] *On Behalf Of *Philip Howarth
> *Sent:* 06 May 2009 20:41
> *To:* osm-midanglia
> *Subject:* [Talk-gb-midanglia] mapnik style sheet
>
>
>
> I finally got round to revamping my old PC (and was pleasantly surprised at
> how easy Ubuntu is to get going from scratch).
>
> After considerable head-scratching, it is now rendering a UK snapshot from
> OSM data using mapnik and serving the tiles via apache (just locally).
>
> However, the rendering that I see is not the same as on the OSM slippy map
> - with problems of very strange changes of things like road colour when I
> zoom in beyond certain levels. It looks (bear in mind I know virtually
> nothing about how manik rendering really works!) as if the road casing is
> being drawn but not the fill. eg trunk roads appear the usual pale green at
> low zooms and suddenly go very dark green as I zoom in. Similar effects on
> primary roads (which go dark red).
>
> I wonder if the osm-template.xml template that I got from
> http://svn.openstreetmap.org/applications/rendering/mapnik/
> is correct / up to date? Or am I likely to have some other issue?
>
> I have played around, hacking the resulting OSM.xml, and I can certainly
> change the map appearance radically (!) but my, as yet, somewhat random
> hacking is a very slow learning route.
>
> If anyone has any knowledge or can point me at rather more digestible
> sources of information than any of the many that I've read so far, I'd be
> very grateful.
>
>     Philip
>
> --
> Philip Howarth
> Cambridge UK
> email: Philip at Howarth.name
>



-- 
Philip Howarth
Cambridge UK
email: Philip at Howarth.name
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