OpenBoulderMap Wiki

A worldwide bouldering map built entirely on OpenStreetMap data. OSM is the source of truth; this site only renders a derived, regenerable snapshot of it.

Data model

Bouldering uses the same climbing=* vocabulary as roped climbing. There is no separate “boulder level”: a single boulder is a climbing=crag relation. Every link in the chain is optional.

problem   node       climbing=route_bottom + climbing:boulder=yes
  │  member of        (optional)
crag      relation   type=site + climbing=crag + climbing:boulder=yes   ← one boulder
  │  member of        (optional)
area      relation   type=site + climbing=area + climbing:boulder=yes
  │  member of        (optional, recursive — areas nest)
(nested area)

# the physical rock is a separate object, not part of the containment chain
physical rock   node / way / multipolygon   climbing=boulder + natural=bare_rock|stone + sport=climbing

Object	Required OSM tags	Notes
Problem node	`climbing=route_bottom` `climbing:boulder=yes` `sport=climbing`	A point at the problem's start. Optional `name`, grades, photo.
Crag / boulder relation	`type=site` `climbing=crag` `climbing:boulder=yes` `sport=climbing` `site=climbing`	One boulder. Members: its problem nodes + the physical rock.
Area relation	`type=site` `climbing=area` `climbing:boulder=yes` `sport=climbing`	Groups crags and/or other areas. Usually named. Recursive.
Physical rock node / way / multipolygon	`climbing=boulder` `natural=bare_rock\|stone` `sport=climbing`	Drawn shape, listed as a member of its crag.

At most one parent per kind — a problem belongs to ≤1 crag, a crag to ≤1 area.
Membership, not geometry — “in” a crag/area means being a relation member. Spatial position is only a discovery aid.
Empty member roles. climbing:boulder=yes is what distinguishes bouldering crags/areas from roped ones.

The UI calls a crag a Boulder when its physical rock is linked, and a Sector otherwise. The viewer reads a regenerable snapshot (climbing.pmtiles + a static index) and never calls the live OSM API.

Grades

Two scales are rendered, each with its own colour ramp. Grades are never converted between scales — a 7A+ is never turned into a V7. Grades are tagged on the problem node.

Scale	OSM tag	Example
Fontainebleau (Font)	`climbing:grade:font`	`7A+`
Hueco / V	`climbing:grade:hueco`	`V6`

The route dot takes the Hueco value first, then Font. Both share a green→red ramp, but the columns below are independent — not a conversion table.

Colour	Font	Hueco / V
easy	`1`–`3+`	`VB`, `V0-`
easy	`4`–`4+`	`V0`–`V0+`
easy	`5`–`5B+`	`V1`–`V2+`
mid	`5C`–`6A`	`V3`–`V3+`
mid	`6A+`–`6B`	`V4`–`V4+`
mid	`6B+`–`6C`	`V5`–`V5+`
hard	`6C+`–`7A`	`V6`–`V6+`
hard	`7A+`–`7B`	`V7`–`V7+`
hard	`7B+`–`7C`	`V8`–`V8+`
elite	`7C+`–`9A`	`V9`–`V17`

Any other climbing:grade:* scale (UIAA, French, YDS, …) is shown in neutral gray, with its label — visible without pretending the app understands it. Ungraded problems are also gray.

Contributing

Add features in OSM and they appear here after the next daily tile refresh. Nothing is ever written to OSM automatically.

OpenBoulderMap editor — desktop-first and boulder-specific. It previews locally, then exports an .osc changefile you upload through JOSM.
iD — the default browser editor, fine for small tag edits.
OpenClimbing — another editor over the same data, strong for drawing routes on photos.

To map a boulder: (1) trace the rock and tag it climbing=boulder + natural=bare_rock|stone + sport=climbing; (2) create the climbing=crag + climbing:boulder=yes relation; (3) add the rock and each problem as members. Problems are nodes tagged climbing=route_bottom + climbing:boulder=yes, optionally with a name and grade.

Photos live on Wikimedia Commons: attach one with wikimedia_commons=File:… and draw the line on it with wikimedia_commons:path.

OpenBoulderMap Wiki

Data model

Grades

Contributing

Links