[OSM-talk] Another point in support of ways as ordered lists

[Andy Robinson]

Nick Whitelegg wrote:
>Sent: 20 September 2006 12:38 PM
>To: talk at openstreetmap.org
>Subject: [OSM-talk] Another point in support of ways as ordered lists
>
>
>Have been encountering numerous strange effects trying to convert OSM data
>to
>a base map for Garmin devices. Almost all of these arise from imperfections
>in the data:
>
>- ways not being *ordered* lists of segments
>- segments not all aligned in the same direction along a way
>
>Admittedly I've been fairly lax about point 2 to date (though not from now
>on...), though I have always tried to follow point 1.

yes, since JOSM has had the arrow and reverse segment direction features
I've been surprised by how much of my early editing was poor in respect of
both of these issues. The segment order is not visible (unless you render it
and the streetname is screwed up) so on a lot of early ways I did I have had
to delete and recreate to get them right. With the arrows turned on in JOSM
and the ability to switch segment direction its much easier to ensure you
get it right with new ways.

cheers

Andy


>
>The Polish format understood by cgpsmapper treats ways as polylines of
>points,
>which is the crucial point.
>
>ISTR a discussion about removing segments from the data model coming up at
>some point,  and changing the data models to nodes, ways (e.g. a one way
>section of a street, or a named section of A road) and super-ways (a whole
>street or a whole A road).  Such a model would reduce the impact of bad
>data
>significantly, and I would be in support of any such proposal if it was
>practical (which, given we've got so far on segments, it might not be)
>
>Nick
>
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