[OSM-talk] Too many nodes?

[Andy Robinson (blackadder)]

Ari,

The short answer is that you can add as many nodes as you like if you think
it better describes what is physically on the ground. I'm always adding
nodes to stuff to make it look right, but I also remove nodes as I go where
I know or find a feature is truly straight.

Cheers

Andy

>-----Original Message-----
>From: talk-bounces at openstreetmap.org [mailto:talk-
>bounces at openstreetmap.org] On Behalf Of Ari Torhamo
>Sent: 18 April 2008 10:22 PM
>To: talk at openstreetmap.org
>Subject: [OSM-talk] Too many nodes?
>
>Hello,
>
>I have a question regarding the amount of nodes that one may use to draw
>a road, and whether the amount of nodes used has a considerable effect
>on the speed of the OpenStreetMap.
>
>I did my first edits to OSM a few days ago. I'll get a GPS device soon,
>but so far my only edits have been adding street names and making roads
>more accurate by adding more nodes to curves, etc. Following these
>edits, another person who has edited the same area earlier, contacted me
>and told me not to add unnecessary nodes to roads that he has made long
>time ago and added that he has already removed the unnecessary nodes.
>According to him using many nodes slows down the rendering and routing.
>
>This made me wonder, what really is the right amount of nodes to use,
>when one want's the curves to be right and look really nice, but not to
>cause any problems by this. Can nodes be added as long as there are
>visible jaggies on the rendered map - even small ones - and just leave
>out the ones which have no affect on rendering (like nodes on a straight
>street)? It would be also good to know, if the speed of rendering and
>routing is a factor that should be concidered? I see now that in a few
>places I added some unnecessary nodes - for example I should have moved
>existing ones instead of adding new ones. Or perhaps I just looked at
>those curves too long - with full zoom - and those jaggies grew up in my
>mind to something bigger than they were :-) On the other hand, in many
>places I think that I made good changes and not many nodes should have
>been removed.
>
>I searched for information on this matter around the OSM web site and
>mailing lists, and found this page (see the section "Accuracy":
>http://wiki.openstreetmap.org/index.php/Editing_Standards_and_Conventions
>I would seem to me that my edits were relatively close to the example
>given there.
>
>I took some screenshots of the changes in question, so that people would
>get a better picture of what I'm talking about. I took screenshots of
>four different places that I edited, and three different versions of
>each of them. The version one shows the situation before my edits, the
>second one after my edits, and the third one after the removal of nodes
>by the original editor. The screenshots are here:
>http://www.flickr.com/photos/65612511@N00/sets/72157604611934407/
>(note that for some reason Flickr shows the pictures in a reverse
>alphabetical order). The zoomlevel used in the images is 16.
>
>It would be nice to get comments from people who know more about what's
>involved.
>
>
>Regards,
>
>Ari Torhamo
>
>
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