Trip logs, CSV and GPX: what to export and why

A drive that is recorded and never exported is a drive you cannot do anything with. The two formats worth knowing are plain comma-separated values, which is a table any spreadsheet will open, and the GPS exchange format, which is the standard way to move a track between mapping tools. They hold different things and they exist for different purposes, and choosing the wrong one is the reason people end up with a file full of numbers when they wanted a line on a map, or a map file they cannot add a column to.

What a trip log actually contains

Behind both formats is the same recording: a series of samples, each with a timestamp, a position, an altitude, a speed and an accuracy estimate, taken roughly once a second while the drive was running. Everything else in a summary is computed from that series. Distance is the sum of the separations, average speed is distance over moving time, top speed is the largest sample that survived filtering, and duration usually distinguishes total elapsed time from time actually moving. Keeping the raw samples is what makes the summary auditable: if a top speed looks implausible, you can go back and see the accuracy figure attached to that sample.

Comma-separated values: the spreadsheet format

A comma-separated file is a table with one row per sample and one column per field, plus a header row naming the columns. Its virtue is that everything opens it and nothing is hidden: a spreadsheet can chart speed against time, filter out samples with poor accuracy, or compute a figure the app never offered. Its limitation is that it carries no notion of a route, so a mapping tool will not draw a line from it without being told which columns hold latitude and longitude. Watch two details when opening one: a locale that uses a comma as its decimal separator can mangle the columns, and a spreadsheet may silently reformat timestamps.

The GPS exchange format: the map format

The exchange format is a small text document that describes tracks as an ordered list of points, each with coordinates, time and usually elevation. Because it is a standard, virtually every mapping application and route planner will import it and draw the line without any configuration. It is the right choice for looking at where you went, for sharing a route, or for combining a drive with other recordings. It is a poorer choice for arithmetic, since adding a column of your own means editing a structured document rather than typing in the next column of a table.

Which one to reach for

If the question is where did I go, export the map format. If the question is how fast, how long, how far, or how does this run compare with that one, export the table. If you need both, export both from the same drive; they come from the same underlying samples, so the figures will agree. A practical habit for anyone testing changes to a car is to keep the table for the numbers and the map file for the context, since a lap or a road is much easier to identify by its shape than by its start time.

What you can do with the files

A spreadsheet chart of speed against time shows braking points and where a road actually opens up. Filtering by the accuracy column removes the samples taken under bridges before they distort an average. Mapping tools will show the track over satellite imagery, colour it by speed, or overlay two drives so the difference in line is visible. Expense records become straightforward: date, start, end, distance, in a table that can be summed. And because the files are plain text, they will still open in ten years, which is more than can be said for most application databases.

Why the log stays on the phone

A drive log is a record of where you were and when, which is among the most sensitive things a phone can hold. The design decision in the app this guide belongs to is that trips are stored on the device, and leave it only when you deliberately export a file and choose where to send it. There is no account, no synchronisation and no upload, which means there is no server holding a map of your movements, and nothing to leak. The trade is that you are responsible for your own backups: if you rely on the history, export it periodically and keep the files somewhere you trust. One habit is worth adopting before a file leaves your hands. Both formats are plain text, so the first and last minutes of a track — the part that begins on your own street — can be trimmed by deleting rows or points in any text editor. A track shared with a forum, a club or an insurer rarely needs to include the driveway it started in, and editing it out afterwards is far easier than un-sharing it.