How to compare a race recording to your plan

Load the GPX from the race you ran. The planner lines it up with the plan at the start, at each aid station where you stopped, and at the finish, then shows where the time went. It is a Premium feature and still in beta.

Why compare at all

A finish time tells you that the plan and the recording ended apart. It does not tell you whether the time went in the first climb, a long station stop or the last descent. The comparison is for finding that out while the race is still fresh, so the next plan can start from evidence rather than a guess.

It is also a check on the model. If the plan is consistently fast on descents, or slow above a certain altitude, that pattern is more useful than the final difference.

What the comparison shows

The comparison has a summary and a table. The summary shows the plan and the recording side by side: distance, ascent, descent, time, pace and aid time. The table adds the difference for each metric and can show distance, ascent, descent, time, pace, aid and modifiers together.

The recorded line appears on the map and the elevation chart, so you can see where the two traces separate.

Why the stops matter

A watch and a route file rarely agree about distance. A few tenths of a percent of drift is normal, and a shortcut or a wrong turn can make one leg read long and the next read short. A single global scale would spread that difference across the whole race.

Instead, the comparison uses the start, each aid station where it detects that you stopped, and the finish as anchors. Between two anchors it corrects the local scale. A difference is booked in the leg where it happened; without the anchors, one wrong turn would make every leg look wrong by the same amount. Station rows are sampled at departure, because the plan's cumulative time includes the time you spent at the station.

If the recording starts more than 2 km from the plan's start, the planner refuses it rather than compare two different courses. A large total-distance mismatch is reported as a warning, not hidden.

An example

The plan column is the Swiss Alps 100 km example. The recorded column is an illustrative recording on the same course; it shows the format of the output.

What it does not do

It does not change your plan or re-plan the race. It shows the differences you give it; it does not explain why a leg was slower. That is for you to read. The recording stays in memory and is not saved. The feature is Premium and still in beta.

Cite this page: “How to compare a race recording to your plan”, UltraTrailPlan, https://ultratrailplan.com/guides/compare-race-recording-to-plan/.