Geo Map Tools

Elevation Profile

Click points on the map to graph the elevation gain and loss along the path between them.

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Click at least two points on the map to see the elevation profile.

Click points on the map to trace a path. The graph shows the elevation along that path, sampled at 41 points.

What the three numbers mean

Gain

Every uphill step added together. A route that climbs 100 m, drops 100 m and climbs 100 m again has 200 m of gain.

Loss

The same sum for the downhills. On a there-and-back route gain and loss come out equal, which is a quick way to check you traced it correctly.

Net

Simply the end elevation minus the start. It says nothing about what happened in between — a brutal route and a flat one can share a net of zero.

Gain is the number that predicts how hard a route feels. Net elevation is almost useless for that purpose, which is why route descriptions quote total ascent rather than the difference between trailhead and summit.

How the chart is built

Your clicked points define a path, but they are not what gets plotted. The path is divided into 40 equal segments, and the terrain elevation is looked up at each of the 41 resulting positions. Those readings are what you see, and the consecutive differences between them are what gain and loss are summed from.

Because the sample count is fixed, the sampling interval depends entirely on how long your path is. Trace a 2 km walk and you get a reading every 50 metres. Trace a 200 km drive and the readings are 5 km apart, which is coarse enough to step straight over an individual pass. Short paths are described in detail; long ones are sketched.

Why your watch will report more climbing

Compare this against a GPS watch or a cycle computer after the same ride and the device will almost always claim more ascent. Both can be reporting faithfully, because they are summing different things.

Any elevation-gain figure is the sum of the rises between consecutive samples, so it depends on how often you sample. A watch recording every second catches every driveway, kerb and dip. This chart, sampling 41 times across the whole route, draws a straight line between points that are hundreds of metres apart and never sees the undulation in between. Coarser sampling always yields less gain — the error is systematic and only runs one way.

● sampled often — catches every climb○ sampled rarely — misses themgrey band: the real terrain
The same route sampled two ways. Coarse sampling draws straight lines across the dips it never sees, so it always reports less climbing — never more.

The opposite bias exists too: barometric devices left to sample very finely can accumulate gain from pressure noise on ground that is genuinely flat. Treat this chart as the shape of the route and a conservative floor on its climbing, rather than as a figure to compare against someone else’s device.

For the elevation at a single spot rather than along a path, use elevation where I am.