OpenStreetMap
Have worked out how to edit GPX traces before uploading using JOSM. This is useful if your trace contains unnecessary waypoints or nodes, or you've inadvertently identified where you live by leaving the unit switched on from the start.
To alter GPX traces
• Start JOSM
• Click the 'Open' button on the toolbar
• Change the file selector from .OSM to .GPX and locate your GPX file
• When the file displays, right click on the file in the 'Layers' window and select 'Convert to Data Layer' from the context menu.
• Press OK to accept the warning message that pops up.
• The GPX layer is converted to a JOSM editable layer. You can now edit it.
• CAUTION. It is very easy to accidentally move the whole trace out of position by inadvertently selecting all points and dragging.
• Use the 'Select' and 'Delete Nodes' tool to remove portions of the track in bulk, or zoom in and move delete individual nodes as necessary.
• When you have finished, right click on the converted layer in the 'Layers' window and select 'Export to GPX...' from the context menu.
• Give the new file a name and press OK. Set the 'Export options' as you want, or leave. Press the 'Export and Save' button.
• This new GPX trace can be uploaded to OSM.
• The converted layer in JOSM can be deleted.
Discussion
Comment from lyx on 17 September 2009 at 21:08
Well, gpx-files are actually cleartext xml files. I found it quite easy to edit them in a simple text editor.
Comment from Vclaw on 17 September 2009 at 22:00
Have you tried this EditGpx plugin for JOSM?
http://wiki.openstreetmap.org/wiki/JOSM/Plugins/EditGpx
It might be easier than converting layers etc.
Comment from Rhubarb on 17 September 2009 at 22:23
There's many ways to skin a cat :P
Each has it's benefits and downfalls.
One way is to use gpsbabel, there's a command you can run that'll prune out nodes within a radius of a specified location(s).
Comment from PerroVerd on 18 September 2009 at 07:36
If you are using the 'Convert to Data Layer' option you may use the 'Simplify way' included in the utils plugin.
Other option is to use the viking program to edit the gpx.
Comment from wieland on 18 September 2009 at 11:34
Instead of
• Click the 'Open' button on the toolbar
• Change the file selector from .OSM to .GPX and locate your GPX file
just drag the GPX file and drop it on JOSM.
Comment from Ævar Arnfjörð Bjarmason on 18 September 2009 at 14:41
The warning about it being easy to move large ways in JOSM doesn't apply anymore. JOSM will display a confirmation dialog if you move a way with more than 20 nodes now.
You can turn it off permanently of course if that sort of thing bothers you.
Comment from Anna_AG on 21 September 2009 at 11:00
RE JOSM moving ways, Ævar Arnfjörð Bjarmason is quite correct, there is a warning dialogue to prevent you moving a whole way - but if I had one change request in JOSM it would be a preference option to never move whole ways - ie by default you cannot move a whole way and as an 'opt in' you can.
Another request would be a preference removing the new confirmation dialogue for merging layers.
I sound like I am moaning now - for what it does JOSM is very very good and very stable - the WMS plugin is great ( a YAHOO imagery overlay ) - great for city editing ) - and other comments talk of the EditGPX which is useful for deleting clusters of points in a CAD environment or GPX trails that are inaccurate due to being in a city etc
cheers bri