Elevation profile – see the height along a path

An elevation profile is a side view of a route: distance along the bottom, height up the side. It shows at a glance where a hike, a bike ride or a pipeline climbs and drops, how high the pass is, and whether the steep part comes early or late. Click on the map to place the start, then the turns of the route; the profile is drawn as soon as there are two points and is redrawn when you drag a point or add one. Move the mouse or a finger along the chart and an orange dot follows the same spot on the map, with its distance from the start, its height and its coordinates. The panel adds up the climbing for you: total ascent, total descent, start and end height, the highest and lowest point, and the steepest grade over 100 metres. The share link stores the clicked points, so the same profile opens again on another device, and the download buttons save every sampled point with its height as CSV, as a GPX track with elevations, or as 3D GeoJSON.

How to use it

1. Search for a town or zoom the map to the start of your route, and click to place the first point.
2. Click along the route at every bend; the profile appears from the second point.
3. Move along the chart to see the height at any spot, and drag points on the map to adjust the line.
4. Switch between metres and feet, copy the share link, or download the profile as CSV, GPX or GeoJSON.

How accurate is it?

How the line is sampled

Each segment between two clicked points is a geodesic on the WGS84 ellipsoid, the shortest path on the real shape of the Earth, calculated with GeographicLib. The tool reads the height at about 300 evenly spaced points along the whole line plus every point you clicked, so a 3 km walk is sampled every 10 m and a 300 km drive every kilometre. For long lines it reads a coarser level of the elevation tiles, matched to the spacing, so the profile loads quickly without losing detail it could show.

Height data and its limits

Heights come from Terrain Tiles, which combine national lidar models (USGS 3DEP in the United States, and several European, Australian and New Zealand models), EU-DEM, SRTM at about 30 m and coarser global models. Where lidar is behind the tile the height is usually within a metre or two; on SRTM it is often within 5–10 m and worse on cliffs and in narrow valleys. The model shows the ground, not bridges, tunnels or the tops of buildings, so a road across a bridge dips to the valley floor in the profile.

Ascent, descent and grade

Total ascent adds every rise along the profile and total descent every drop. Ups and downs smaller than one metre are treated as noise in the model and are not counted, which keeps flat routes from showing climbing that is not there. The figures depend on the sample spacing: a route with many short climbs reads lower on a long line sampled every kilometre than in a GPS track with a point every few seconds. The steepest grade is the largest height change over any 100 m stretch, in percent.

Good to know

Draw the route, not a straight line

A trail or road that winds around a hill climbs less steeply than a straight line over the top. Click at every bend of the path you will actually take, or the profile shows the shape of the terrain under a straight line instead.

Comparing with a sports watch

Barometric watches and apps often report more ascent than a map profile, because they count every small rise and drift with the weather. Differences of 10–20 % on a day hike are normal; neither number is wrong, they measure different things.

Water, bridges and tunnels

Over a lake the model gives the water surface and at sea it can give the sea floor as a negative height. A tunnel or a bridge is not in the data, so the profile follows the mountain above or the valley below.