[OSM-dev] Altitude data & (cycle) route profiles

Frederik Ramm frederik at remote.org
Sat Mar 29 11:28:35 GMT 2008


> I was thinking about adding nodes to long ways. This may sound a bit
> ugly at first, but not if you consider the fact that the SRTM actually
> provides real information about these points along long ways. It is
> just that the latitude and longitude are not reliable, only the
> altitude is.

Doesn't sound very good to me, adding nodes to existing ways just to
import height... I'd rather have the height as a separate info. Much
like a road that enters a forest; I don't put a node at that point
just to say that this node represents the road entering the forest - I
just model the forest as an extra entity and whoever needs to can
compute the point.

Also, having SRTM data as nodes in OSM touches on the often discussed
topic of immutable data. Would it be ok for people to edit individual
SRTM nodes? 

I'd also recommend to first do an analysis about the impact on OSM
altogether, i.e. by how much would the planet file grow by importing
SRTM data like you suggest? If renderers would start to use that
information, then we'd suddenly have not a single "empty" tile
anymore, every land tile on the planet would have information on it
(right?), how would taht impact storage requirements for tile servers
etc.? - Not saying that any of these could be a show-stopper, it's
just that such an analysis should be part of the plan.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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