County Maps US

Tools Elevation, time and sun

Elevation Profile

Click out a route, or follow the roads, and the profile is sampled along it. The route is encoded in the URL so you can share it.

How to use it

  1. Click the map to drop route points in order, or type a place and press "Add point".
  2. Tick "Follow roads" to snap the route to the road network instead of straight lines.
  3. Press "Build profile" to sample the route and draw the chart.
  4. Read the climb, descent, high and low points and the steepest stretch; export as GPX with elevations.

How it works

The route is either straight segments between your points (great circles, sampled every 2 km at most) or, with "Follow roads", the driving route returned by the public Valhalla router at valhalla1.openstreetmap.de. The line is then resampled at even spacing, at most 300 samples, and each sample is sent to the Open-Meteo elevation API, which reads the Copernicus GLO-90 terrain model in batches of 100 points.

Total climb and descent add up the rises and falls between samples, ignoring changes under 2 metres so that model noise does not inflate the totals. The steepest grade is the largest height change over any stretch of at least 100 metres. Because the model has 90 metre cells and the samples can be tens of metres apart on a long route, a short sharp hill can be smoothed away and bridges are drawn as the valley under them.

Questions

How many points can a route have?
Up to 25 route points. Long routes are still limited to 300 elevation samples, so a 300 mile drive is sampled every mile and only shows the broad shape.
Can I export the profile?
Yes, as a GPX track with an elevation on every point, which opens in Garmin, Strava, Google Earth and most mapping apps.
Why does the elevation gain differ from my GPS watch?
Watches sum thousands of tiny barometric wobbles and usually report more gain. This tool uses a smoothed terrain model with a 2 metre threshold, which is closer to what a paper map would give.

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