[OSM-talk] JOSM update

[Steve Hill]

On Fri, 28 Mar 2008, Frederik Ramm wrote:

>  and you can also limit the
>  length of these GPS connection lines (draw.rawgps.max-line-length=x,
>  in metres), for those cases where you get crazy zig-zagging.

I had noticed a while ago that JOSM appeared to handle GPX files 
incorrectly (and presumably the same goes for GPX data retrieved from the 
OSM server) - Not sure if it has been fixed (I'm using a relatively old 
JOSM at the moment):

The GPX files consist of <trk> elements (tracks), with each track 
containing one or more <trkseg> element (track segment).  JOSM seemed to 
be joining the end of a <trkseg> to the start of the next <trkseg> rather 
than leaving them unconnected.  The <trk> elements themselves are handled 
correctly though - they are left unconnected.

This might be the cause of a lot of the crazy zig-zagging (which actually 
makes the GPS data completely unusable in some locations - Nottingham, for 
example, is totally obscured by the zig-zagging lines if you ask JOSM to 
retrieve the GPS data from the server.)

Which brings me to another point - why not run a sanitiser across the 
database to try and remove obviously broken GPS data.  For example, if the 
distance between two GPS points exceeds several hundred metres they 
probably shouldn't be considered part of the same track segment so this 
could be fixed in the database itself.

  - Steve
    xmpp:steve at nexusuk.org   sip:steve at nexusuk.org   http://www.nexusuk.org/

      Servatis a periculum, servatis a maleficum - Whisper, Evanescence