How to Open, View and Analyze a GPX File Online

Someone sends you a route for the weekend, a club ride or a forest track a friend drove last summer, and it arrives as a .gpx file, and the first question is always the same: what am I actually looking at? A GPX viewer online answers that in seconds, with no software to install. Drop the file in, and you get a map, the numbers and a chart of every climb.

The harder part is knowing what those numbers mean, and when to trust them. In this post we walk through opening a track in the free TrailX analyser, then go through each figure and chart one by one: what it tells you, what it doesn't, and how to tell a clean track from a messy one.

If you're brand new to the format, our explainer on what a GPX file is covers the basics. Here we'll assume you have a file and want to understand it.

Opening a GPX file: the short version

On a computer, a GPX file is just text, so double-clicking it usually opens a text editor full of coordinates. You need something that draws it on a map, and our step-by-step guide on how to open a GPX file covers Windows, Mac and the common options in detail. If the file is on your phone, the guide to GPX on iPhone and Android is the quicker route.

For a fast look with proper analysis, though, the browser is the easiest place to start.

Using TrailX as a free GPX viewer online

Here's the whole process:

1. Go to Upload & analyse. You don't need an account to view or analyse a file.
2. Drag your GPX onto the page, or click to choose it. KML, KMZ, GeoJSON, TCX and CSV work too.
3. Wait a moment while it draws. The route appears on an interactive map, with any waypoints from the file.
4. Scroll through the stats, the elevation profile and the gradient breakdown.
5. If it's a route worth sharing, sign in and publish it.

The analysis runs in your browser. Your track only leaves your device if you choose to publish it. The one exception is that the page looks up place names and water crossings online, so it needs a connection for those.

If your file is in another format, the analyser will usually open it directly. If you need a different format for a particular device or app, the free format converter turns any of GPX, KML, KMZ, GeoJSON, TCX and CSV into any other, also without uploading anything. We cover that in more depth in our post on converting GPX files.

What each number tells you

Once the track is on screen, you'll see a panel of figures. Here's how we read them.

Distance

Distance is the sum of the straight lines between consecutive points. That sounds simple, but it means the number depends on how the track was made. A recording with points every few metres follows every switchback. A route drawn by hand with a few dozen clicks smooths them out and comes up short. Neither is wrong; just know which one you have.

Total ascent and descent

This is the figure that decides how hard a day feels. Compare two of our trails: the Toronto Waterfront Walk is 21.6 km with 13 m of climbing, while the Gössler Alm Hike packs 1,205 m of ascent into 6.5 km. The second is a third of the length and many times the effort.

On a loop, ascent and descent should come out about the same. On a one-way route, the difference between them should roughly match the difference between start and finish elevation. If they're wildly off, the elevation data is worth a closer look (more on that below).

Min and max elevation

These are easy to skip, but they matter in the mountains. The Annapurna Circuit over Thorong La climbs 4,164 m over 96.9 km, and the maximum elevation is the number that tells you about altitude, cold and how much time you'll need to acclimatise.

Reading the elevation profile

The elevation profile is the chart of height against distance, and in the analyser it's synced with the map. Hover over any point on the chart and a marker shows you exactly where that is on the route. It's the quickest way to find where the big climb starts.

We've written a whole post on how to read an elevation profile, including false summits and turning a profile into a time estimate, so we won't repeat it here. The short version: look at the shape before the numbers. A steady ramp, a staircase and a sawtooth can all add up to the same total ascent and feel completely different underfoot or on the pedals.

Gradient distribution

Below the profile, the analyser splits the route into three bands:

• Flat: 0–3 %
• Moderate: 3–8 %
• Steep: over 8 %

This is one of the most useful views for comparing routes. Two rides with the same total ascent can be a pleasant spin or a grind, depending on whether that climbing is spread across long moderate drags or concentrated in short steep ramps. For walkers, a big steep share usually means slower going on the descents too. For a heavier vehicle, it's a hint to look at the steep sections on the map and check what surface they're on.

Total ascent tells you how much climbing there is. The gradient breakdown tells you what kind of climbing it is, and that's usually what your legs care about.

Time and speed (if your file has timestamps)

A GPX file recorded on a watch, bike computer or phone usually stores a time for every point. Routes drawn on a planner usually don't. If the times are there, the analyser adds four more figures.

Total time is simply the gap between the first and last point. Moving time leaves out the stretches where you were standing still: lunch, photos, waiting at a junction for the group. The difference between the two is often surprisingly large, and it's the honest number to use when planning. If a friend's total time was eight hours but their moving time was five and a half, you'll want to know which one you're comparing yourself to.

Average moving speed is distance divided by moving time. It's a fair way to compare your pace with someone else's on the same route. Max speed is the fastest stretch between any two points, and it's the figure most likely to be nonsense. A hiker "reaching" 70 km/h is almost always a single bad GPS fix, not a sprint.

Water crossings

The analyser counts the places where your route crosses mapped rivers and streams. For hikers, that might mean wet feet or a bridge worth checking. For off-road drivers and cyclists, it's a list of spots to read up on before you go, because a ford that's a trickle in August can be impassable after rain. The count is based on map data, so treat it as a prompt to look, not a guarantee of what you'll find. Our safety guidelines have more on judging crossings on the day.

Sanity-checking a track

Not every GPX file is a good one. Recordings pick up errors, and planned routes can be rough. Before you trust a file for navigation, we run through these checks.

GPS jumps. Zoom in on the map and follow the line. Spikes that shoot off to one side and come straight back are bad fixes, common in deep valleys, cities and dense forest. Each one adds fake distance and often a crazy max speed.

Noisy elevation. Look at the profile on a section you know is flat, like a lakeshore or a valley road. If it's jagged with constant small ups and downs, the elevation came from a GPS chip rather than a barometer or a terrain model, and the total ascent is probably inflated. The shape of the big climbs is still useful; the exact total, less so.

Gaps. A long straight line cutting across a hillside usually means the recording paused or lost signal. The route on the ground went somewhere else. Check the point spacing figure too: a file with very few points spread far apart will cut corners everywhere, which is fine for an overview and risky for following on a phone at a junction.

Start and end. Does the track start at a trailhead you recognise? Some recordings include the drive to the start.

Direction. The profile reads left to right from the first point. If you plan to walk or ride it the other way, read the profile right to left. Trail pages on TrailX also offer a reversed GPX export. A steep ascent becomes a steep descent, which is a different day.

If a file fails several of these, it's often quicker to rebuild the route than to fix it. You can redraw it in the Route Composer by clicking stops along the way, pick the Hiking, Cycling, On-Road or Off-Road profile, check the new elevation profile and export a fresh GPX. Our guide to precision GPX files explains what makes a track reliable enough to navigate with.

From viewing to using

Happy with the track? Import it into the TrailX app and download the regional map so it works without signal. For topographic, satellite and 3D views, see our post on viewing a GPX file on a map. It's also worth comparing it with published trails in the same area, where you can download GPX files that have already been checked. And the GPX 1.1 documentation from TopoGrafix remains the original reference for the format itself.

Where to next?

• Analyse a file now: drop a GPX into the free analyser, no login needed.
• Need another format? Use the free format converter for KML, KMZ, GeoJSON, TCX or CSV.
• New to GPX? Start with what a GPX file is and GPX vs KML.
• Make sense of the climbing: how to read an elevation profile.
• Plan your own route: build one in the Route Composer and export it as GPX.