[OSM-talk] Large Rivers in general, mapnik rendering in Particular

David Groom reviews at pacific-rim.net
Wed Feb 13 11:59:29 GMT 2008


> ----- Original Message ----- 
> From: Igor Brejc
> To: David Groom
> Cc: David Earl ; Artem Pavlenko ; talk Openstreetmap
> Sent: Monday, February 11, 2008 4:04 PM
> Subject: Re: [OSM-talk] Large Rivers in general, mapnik rendering in 
> Particular
>
>
> David Groom wrote:
> I'll edit the wiki.
>
> Could you put some visual examples, please?
>
>
> Artem, what i had in mind is now shown on
> http://wiki.openstreetmap.org/index.php/Relations/Proposed/Rivers
>
> David G
>
>
> I'm a bit late in entering this discussion, but at the first glance I see 
> at least one problem with this proposal: representing tributaries 
> (http://en.wikipedia.org/wiki/Strahler_Stream_Order), which must be 
> treated separately, since their usually have their own names. Either you 
> would have to define an OSM way splitting the main river and the tributary 
> (which in a sense defeats the idea of this proposal) or you would let the 
> renderer assume that it can draw such a segment by itself (which can 
> sometimes be problematic, I suppose).
> I'm not against letting renderers do their jobs, but I think we should not 
> presume that all devices will have CPUs powerful enough to provide 
> interactive maps by processing complex geometry algorithms. Drawing 
> something like this, for example: 
> http://en.wikipedia.org/wiki/Image:Mouths_of_amazon_geocover_1990.png :)
>

Thats a good point.  I'm reasonably happy with the proposal for defining 
large rivers as closed areas, as outlined in the proposal 
http://wiki.openstreetmap.org/index.php/Proposed_features/Large_rivers  . 
The proposal at 
http://wiki.openstreetmap.org/index.php/Relations/Proposed/Rivers  was an 
attempt to satisfy some peoples concerns about a"segment" being drawn across 
the river to close the area, but I think in practice it probably causes more 
problems than it solves.

David

> Igor
>
>
> -- 
> http://igorbrejc.net 






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