Merge with other data

[KenS]

I've started using the iBike software feature that lets me merge with, in my case, a Garmin TCX trace of my ride to get Lat and Lon.

I've found a couple of problems with this:
When I use the Garmin timestamps the output often had them a bit jumbled, some timestamps are reused and out of order.
Most of the time the only thing needed to synchronise the two sets of data is to do a small timeshift so it would be good if the merge feature allowed that, maybe even as a manual operation (i.e. type in an offset). Basically I've taken to doing just that by loading the iBike file and the TCX into a spreadsheet and graph speed against time then fiddle with the time difference till they align. Having done that I now have an accurate time difference between them (which happens to be 20 seconds). I also calculate the least squares fit so I know if I'm dialled in right.

Another problem is that whilst iBike does a reasonable interpolation of Lat and Long it only goes to 5 decimal places whereas the Garmin does 6. At least that's how it comes out on the CSV export. So the interpolation tends to appear as a series of "steps" instead of a smooth line. This affects my current pet project where I graph Abs Wind speed against heading to see if I've got the iBike positioned in reasonably "clean air" setup. Just an experiment but having the route moving along at right angles messes up the graph.
I've also tried using GPS Babel to do the interpolation on the TCX file which is better but it has other issues.

So to summarise a couple of features:
1) Allow a simple time offset to merge iBike files with other data
2) Use 6 decimal places on the Lat and Long interpolation (if that's not already happening) and output same to the CSV file

[Velocomp]

We will report your findings to guru Travis.

[KenS]

A few attachments to illustrate the issue:
As you can see in the TCX file the lat and long use 6 decimal places. In the ibike CSV export there are only 5 decimal places.
There is also a discontinuity in the ibike CSV file at 11:00:52 (row 108) where it skips back 8 seconds.
By my own calculations, the ibike timestamps are about 10 seconds faster than the garmin

[KenS]

Another issue is that when I want to use the ibike timestamps I always get the garmin ones. On the "Merge signals form another ride file" screen it doesn't make any difference whether I leave the "Time Stamp" box checked or unchecked under "Use from Other Ride File" - I always get the Garmin time stamps.
I'm using Isaac 1.0.2
Attaching the exported csv after trying to use ibike timestamps

[racerfern]

Ken,

Switch your Garmin 705 from Smart Recording to Once per Second just like you have the Newton. Smart recording can reduce the recording rate to as low as once every eight seconds and Isaac has to do a tremendous amount of interpolation to try and solve for a good trace. Once per second recording will solve that. Additionally, check your setting in the 705 to see if auto pause is on. I keep auto pause on and set to a custom speed of 1.5mph which gives me a riding time relatively close to the Newton. If you have auto pause off or set to "when stopped", GPS drift can make the unit continue recording even if you're not moving and the GPS points can end up "backwards".

As far as bringing in the timestamps whether checked or unchecked, I can't think of a reason why you would bring in LAT/LON and not bring in timestamps. It gives you your location and the actual date and time including pauses, stops, etc. What would be your goal in bringing in LAT/LON without bringing in the timestamp?