Segment Atlas — The road, replayed.

Trends

Pace plan

Modeled · your recorded rides don't change

Finish in a time Ride at a power

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Calm Headwind Tailwind

Sections

Section	Power	Split	PR	Difference

Best window: the start time when the forecast wind makes your target easiest, on the next four days. Forecast conditions and how ready you are stay separate.

Maybe

Conditions—versus calm

Readiness—declared limit only

Forecast confidence—coverage unavailable

Best start window

lower required power is better

Evaluating today’s alternatives…

Section plan

forecast power range

Section	Split	Required	Range	Wind

Help & getting started

Ride files stay on this device unless you explicitly share them.

Privacy

FIT and GPX files are parsed locally and saved to this browser's IndexedDB. Weather requests send the course location and effort time to Open-Meteo, not the ride file. Share and export actions run only when you choose them.

Optional Google sign-in syncs route outlines, sections, and ride summaries across your devices. Raw ride files, GPS and sensor streams, terrain, and settings stay in this browser. Open Account to manage sync.

Read the full privacy policy

Supported ride formats

FIT and GPX activity files
Gzipped FIT or GPX files
Route-only GPX files, replayed with synthetic timing

A complete comparison effort must pass near both canonical gates on the selected route.

Export and portability

Open Share in the route tools for privacy-previewed images, CSV data, supported replay video, and portable Segment Atlas sessions. Legacy `.hawk-hill-session` and `.climb-session` files remain supported.

Why is a control unavailable?

The Pogačar benchmark is available on Hawk Hill and requires one complete effort. Compare requires two complete efforts on the selected route that match both gates. Hover or focus an unavailable control for its current requirement.

Map legend and credits

Marin Headlands, CA · 1 m lidar terrain

Mapped roads · route and approaches

Rider trail · solid series color

drag to orbit · pinch or scroll to zoom · right-drag to pan
drop a .fit / .gpx ride anywhere to create a replay

Keyboard shortcuts

Space play or pause
← / → seek five seconds
[ / ] decrease or increase playback speed
F toggle the follow camera
M switch between satellite and topo maps
B build a new route from a ride
C start comparison, then show or hide its details
? open this shortcut reference
Esc close the active drawer

Shortcuts pause while focus is in a button, link, or form control.

Share

Show ride names Show dates Show the GPS route

More: a video, the data, a session file

A session file carries these rides, settings and plans to another browser, without the original FIT or GPX files. Opening one adds its rides to this browser's library.

Open session file

Nothing leaves this browser until you share or save.

Marin Headlands · Survey of the route

Hawk Hill

Loading elevation data…

Elevation Imagery Scene Roads Library

USGS 3DEP · 1 m grid · Segment 229781

Route tools

Rename ride

Performance

See your ride in context.

Build a route