copying position data

A track is a list track points. A track point records the horizontal position (lat/lon) in decimal degrees (+N/E; -S/W), elevation (relative to MSL, not gps elevation) in meters and the date/time the point was recorded (UTC, not local). From these data all other fields (leg distance, course, leg speed, etc) are calculated later (i.e. not saved in the file).

The changes you are requesting require altering the horizontal position and/or time data in a .gpx file (these files are text files and can be open with any text editor e.g. Notepad). It is possible to open a .gpx file with Excel – it will parse the data into columns. I suspect that a program exists that will convert a csv file into a gpx file, but I don’t know of one. So, it may be possible in Excel to delete all the columns except Lat, Lon, Elevation, Time, make your changes and save as a csv file and convert that to a track gpx file with a third party application.

Since the GPS system does not record true positions, the easiest course of action would be to simply delete extraneous points (the fields you are interested in will automatically be recalculated). I would suggest you duplicate (not copy) one of your tracks and try this first to see if it gives satisfactory results. Points can either be selected and deleted in the Track Properties window or by using the eraser tool (left mouse click for one point at a time or hold down the left mouse button and drag for multiple points) in the map window (you can undo a change with ctrl+z).

To convert csv to gpx you might want to try GPSBabel

http://www.gpsbabel.org

Hi, i have some tracks that were recorded incorrectly by my Fenix. I'm working on that issue, but was trying to figure out how to fix the track in Basecamp. I have done several out-and-back hikes where some section of the track gets off course or sometimes i'm traveling at 665mph! What i'd like to do is to use the correct position data (from whichever direction) to put it in the divergent sections. I'd like to keep all data (elevation, leg speed, leg time, etc), but overwrite the Position data. How do i do this? Like, is there a way to download the track as an Excel document so i can just copy/paste the data in the Position column?

And are there hierarchies to the data columns, such as the Leg Time, Position, and Time are used to extrapolate the Leg Speed, Leg Course, and Leg Distance? So if i can just overwrite the Position data, will it calculate things afterwards?

Hello Smith,

Using BaseCamp you cannot just overwrite the position data.

You can however delete certain trackpoints and sometimes that will correct a crazy 665mph speed spike.

I do it by trial and error 2-3 points at a time and use undo a lot until its fixed.

I've been trying various file formats, but can't seem to find the right combination. When open the .gpx in Excel it is able to load the tables, and I delete the extrapolated rows, and i fix my position data, and then go to save it but i don't know what file type to save it as. There's a couple options for .csv, as well as a bunch for .xls .xlt .txt .xml .html etc etc etc... then using the GPS Babel, i have options for what the converted output file will be. The cool thing about the Babel software is that it will tell you if it will translate over the Waypoints, Routes, or Tracks depending on what the imported file type is and what the output file type is. I am assuming i want all three to be translated? Anyway, i've tried a couple different variations, but Basecamp doesn't seem to like some and the only ones it does like are if my track is a bunch of Waypoints. I can make a route out of that, but it does a crazy dot connection and my 12 mile hike ends up being over four thousand miles long. So, anyone have successful experience with this? I am so close...

Hello Smith,

Attach a copy of your original file and spell out what you want repaired.

Once I can see what you are dealing with then I can tell you how to fix it.

My gpx file is 4.69 Mb, so it looks like if i can convert it to a fit file i will be allowed to upload it. How do i do that? Thanks for the help!

Hello Smith,

You should be able to ZIP that file down and attach it.

If it is still too big then get a free DropBox account and post the link to your file.

you know, i think i realized that this won't work either because i have more data points (indexes) on the way up the trail than on the way down since i was moving faster going down. So trying to use the same lat/lon data won't translate over. I have 2338 indexes in the "divergent" section on the way up, but only 1503 indexes on the way down for that section. So i'm short some 835 lat/lon data indexes to be able to copy over the position data to try and get things corrected. Maybe the only way to fix it is to individually move the 2338 points. Anyway, here's a dropbox link to the uncorrected file. Thanks for all the help.
https://www.dropbox.com/s/yparmxojyucehth/Pico%20and%20Killington.gpx?dl=0

Hello Smith,

I have looked at your track. It seems that part of the problem is that that trail has a lot of tree cover. Tree cover weakens the satellite signal and combined with the small antenna on your Fenix the result is an inaccurate track with large jumps in the coordinates as the Fenix changes satellite connections when openings in the tree cover permit a different (sometimes better) view of the sky. Those jumps cannot be fixed because there are no coordinates to manipulate.

That being said, there is a lot that can be done to fix your track.

The section from the Pico Cabin up to Killington and then all the way back down to where you started at Hwy4 looks good.
I would make that piece into 3 Laps.
Lap3 = Cabin to Killington.
Lap4 = Killington to Cabin.
Lap5 = Cabin to Hwy4.

Are you sure you used the same trail from Hwy4 up to Pico that you used going down?
If yes, then the going down section can be inverted and substituted at the start.
That would become Lap1 = Hwy4 to Cabin.

The track wandering around Pico Peak can be partially fixed using tracks from others that I have.
That would become Lap2 = Pico Peak.

What say you ?

yeah! I used the same trail going down as going up (except for the side trail up to Pico on the way up), and those laps seem a like a good way to go. The cabin would be a good marker since it seems to have locked on after that point.