[OSM-newbies] Node placement

[David Groom]

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----- Original Message ----- 
From: "Thomas Rynne" <thomas.rynne at gmail.com>
To: <newbies at openstreetmap.org>
Sent: Monday, April 23, 2007 4:21 PM
Subject: [OSM-newbies] Node placement


> Hi,
> I've just started mapping Aldershot and have a few questions.
>
> I've gone out and cycled around for 1/2 an hour and have created a
> GPX file and opened it in JOSM. I understand that the next thing is to
> create nodes, segments and ways.
>
> I had expected that these would be sort-of generated directly from the
> GPX file and I would add more information like street names etc.
> However, from what I have read I now think that I draw nodes manually
> over the top of the GPS traces, using the traces a a guide. Is that
> correct?

yes

>
> Do I just place the nodes roughly? Is there any special technique?
> Should I cycle along streets in both directions so I can find the middle?

Theoretically yes, in practice I guess it would depend on how wide the 
street is.  However the advantage of travelling along a road more than once 
is that you can "average out" the minor variations cased by inaccuracies in 
satellite reception.

>
> How many nodes should I create per road. Would a typical straight road
> consist of two nodes and one segment? How straight does it have to be
> to only get 2 nodes?

There are no hard and fast rules, basically draw as many nodes as is 
necessary to get a reasonable representation of the road.  Therefore curved 
roads get more nodes, straight roads can make do with two, one at each end, 
unless there are roads coming off of it in which case there has no be a node 
at each junction.

>
> Also, I took some photos of street names to use the JOSM geo-tag
> feature but can't find any information on how to enable it in JOSM. Is
> there a web page I am missing?
>
> thanks
> Thomas
>
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