I have a GPX file with what looks like a single rogue point miles away. It happens at a point where I switched off logging then switched off the GPS in the car for a while before continuing from the same point later. As far as I know I switched tracking back on when the GPS was back working. I could trawl through the GPX file with a text editor but is it possible to do it with some GUI such as Potlatch.
Prune http://activityworkshop.net/software/prune/ is your friend. I normaly use it to conceal where i live.
It was the thumbnail picture of the plot under GPS Traces showing just a straight line which alerted me to the problem. I actually managed to cure the problem by editing the GPX file with Wordpad. Six readings were corrupt with longitude values 30 deg out probably just after I restarted logging. All was ok after removing these entries.
Thanks for the info about Prune. It took ages to get working until I noticed that Windows had renamed it a zip file instead of a jar file. Loading the corrupt version of the file into Prune does not immediately show a problem as there are no plot lines to the rogue points to show. However a small block of missing altitude data showed there was a problem. Moving the cursor to this point showed the rogue plots which I was able to delete.
All my original plots started from my house so there is rather a birds nest of plots around here which I will remove with Prune. I now donÂ’t start plots until I am some distance from the house. Thanks again for the info.