[OSM-dev] ogr2osm coordinate precision

[Sebastiaan Couwenberg]

On 06/30/2014 11:35 PM, Frederik Ramm wrote:
> Hi,
> 
> On 06/30/2014 11:08 PM, Sebastiaan Couwenberg wrote:
>> This way the coordinates downloaded from the API would match those from
>> ogr2osm, and needlessly modifying the node coordinates with a higher
>> precision could be prevented.
> 
> Why would anyone use JOSM's "replace geometry" method to replace a
> geometry with something that looks identical?

I can't speak for anyone, but I use it to update both the geometry and
tagging with the new data from ogr2osm.

My use case are the administrative borders in The Netherlands and the
~monthly updates affecting a subset of settlements.

Using Replace Geometry preserves the history of the objects, enables
easy tag merging, and restores borders to their official geometry.

The ways only look identical at high zoom levels, the low zoom levels
show that they aren't identical.

At least merging the start and end nodes of the way to replace is
required to not break the ring when replacing the geometry.

Even though the start and end nodes have not moved and still use the
same coordinates (albeit with a higher precision), the osmChange will
modify the node but only increase its version still setting the same
coordinates.

That would be the JOSM bug Paul hinted at, and the source of my quest to
improve the extracts I use to maintain the boundaries in OSM.

Kind Regards,

Bas