[OSM-talk] Contours server (was: Re: ski pistes)

[Steve Hill]

> Contours layer presented by openpistemap is simply great. Does it
> exist a server publishing only this layer?

I'm not sure how that would work - you really need the contours data set 
to be the bottom layer, with the normal layers on top of that (is it 
possible to ask OpenLayers to render the OSM Mapnik tiles on top of 
another layer?  I suspect not since the tiles aren't transparent...)

OpenPisteMap only has contours data for specific areas because 
the data set is pretty enormous (I did try converting the whole SRTM3 data 
set to shapefiles - I gave up by the time it had done about 3/4 of Eurasia 
and sucked up over 100 gig of disk space.  I haven't tried pulling the 
whole data set into PostGIS yet - I wonder if that is any more efficient).

Another consideration is that the contours tiles have to be tailored to 
the map type a bit - for example, the cycle map renders the contours 
closer together (i.e. it introduces each set of contour lines at lower 
zoom levels than the piste map).  The mountainous terrain of the pistes 
results in unreadably close contour lines if you just try to apply the 
cycle map styles.

> I'm working on Viking, a desktop GPS data editor capable of rendering
> data on top of image downloaded on line. Having a contours layer would
> be usefull to prepare hicking.

For that kind of application, it might be better to implement an API to 
retrieve the contour shapes from an online database and render them 
on-the-fly in the application.  That would allow the user to tune the 
settings to suit the terrain.

  - Steve
    xmpp:steve at nexusuk.org   sip:steve at nexusuk.org   http://www.nexusuk.org/

      Servatis a periculum, servatis a maleficum - Whisper, Evanescence