Guides

How to do real things with our apps, on real streets, trails and files, and the notes we keep while building them.

Plan a route, then run, ride or hike it

Draw a route that follows the running path, the bike path or the trail, and hear every turn on the way.

Routes · 6 min

Plan a 5K route around your house, then run it with the turns in your ear

Draw a 5K loop in GPX Explore with a few taps and the route follows the running paths by itself. Then run it with headphones on and the phone in your pocket, every turn spoken.

Routes · 5 min

Plan a bike ride on a national park bike path and follow it turn by turn

Draw a ride in GPX Explore with Follow Roads (Cycling) and the route keeps to the bike path beside the road. Check the climbs and the canyon in 3D, then ride it with spoken turns, a climb panel and the Lock Screen. Zion is the example.

Routes · 5 min

Plan a national park hike and follow the trail with spoken directions

Draw a hike in GPX Explore with Follow Paths (Walking) and the route keeps to the trail and its switchbacks. See the climbs and fly the trail in 3D, then hike it with the junctions spoken and the screen off. The Mist Trail in Yosemite is the example.

Tracks, workouts and walks you keep

Record a walk with your photos on the route, get your Apple Watch workouts out as GPX, and open any GPX file.

Tracks & workouts · 1 min

How to export Apple Watch workouts as GPX, with heart rate

Apple Health keeps every route your Apple Watch recorded, but not as a file. Here is how to get any workout out as a GPX file with heart rate, cadence and power, one at a time or all at once.

Tracks & workouts · 2 min

How to see heart rate and power from a GPX file

GPX files from Garmin, Strava, Wahoo, Coros, Suunto and Apple Watch carry heart rate, cadence, power and temperature on every point. Most viewers ignore them. Here is how to see them, and what the numbers mean.

Tracks & workouts · 2 min

How to open a GPX file on a Mac

Three ways to open a GPX file on a Mac, what you will see in each, and how to make one app the default for every .gpx file.

Maps, land and terrain

Build a layered KML map, choose the right map app for a file, and see what the ground data can and cannot tell you.

Maps & terrain · 8 min

Make a race-day map in KML: the course, water, medical and parking, layer by layer

How to build the map a volunteer team needs for a charity 5K, as one KML file with a folder for each kind of thing: a course that follows the streets, start and finish, water, mile markers, a medical circle, parking and closures. Drawn in KML Explore on Mac, iPhone or iPad, opened anywhere.

Maps & terrain · 12 min

One file, one job: why GPX Explore, KML Explore, Geo Measure and Geo Elevation are four apps

A developer’s look at why ObjectGraph makes separate map apps: a GPX track, a KML map, a measurement and the ground under it are four different data models with opposite rules, and one app holding all four would have to break some of them.

Maps & terrain · 5 min

Boston Harbor was 15,728 meters high

Our elevation server said a spot on the Boston waterfront stood nearly twice as high as Everest. The cause was a 2017 flaw in the open terrain data much of the web uses, plus one bug of our own. How I found every bad height on the planet and fixed them in place.

Maps & terrain · 5 min

Two terabytes of terrain on one box: the elevation API behind Geo Elevation

How elevationapi.geosq.com serves elevation profiles for the whole planet from our own server: OpenTopoData, 22,912 ASTER tiles, 65,341 Mapzen tiles, and a 100-millisecond answer.

Developer notes

Problems we hit in our own work on local models, MCP, Apple platforms and the web, and how we fixed them.