How to find source of mass-added tags?

Help and support
1

bicycle=dismount | Tags | OpenStreetMap Taginfo - from graph you can clearly see appearance of 50k instances of this tag in some bot edit, quite recently. I am interested in investigating what happened.

Does anyone has tool/capability to locate relevant edits or area where it happened?

(I have some, but they are incapable of handling so popular tag)

BTW, if you take look at bicycle=no | Tags | OpenStreetMap Taginfo it is clear that someone mass retagged bicycle=no to bicycle=dismount

6 Likes
2

One thing that comes to mind is using Geofabrik’s local Taginfos https://taginfo.geofabrik.de/ and basically doing a breadth-first search: check each continent for that 50k jump in dismount tag counts, then check each country on the continent that has the jump (probably checking more active countries or otherwise “usual suspects” first), then check the country’s subregions if any. Then do an Overpass search in the identified area and click around for recently changed values to find the changesets.

I don’t know if there’s more automated ways of doing this.

A higher resolution of the Taginfo map of tag uses, or a heatmap, would be helpful in this case.

(I can DM you the answer for this specific query, but I am assuming in this thread you want to address the general technique.)

3 Likes
3

Looks like Quebec, see bicycle=dismount | Tags | OpenStreetMap Taginfo Quebec

4

We know the approximate date, so let’s query for timestamp objects that fall within that date and hope they haven’t been modified since:

way[bicycle=dismount](if: timestamp() > "2025-09-07T00:00:00Z" && timestamp() < "2025-09-09T00:00:00Z");
out center;

We open Overpass Ultra to make sure your browser isn’t dead and get ~62,000 objects, hooray. Let’s find where they’re most numerous:

Changeset: 171660464 | OpenStreetMap

What if all objects were changed later (for example, as a result of a revert)? Add [date:"..."] to the beginning of the query.

It’s surprising that Overpass allowed me to compare timestamp() and a string. For some reason, everything breaks if I wrap the string in the date() function.

The heatmap display in Overpass Ultra can also make it a little easier to find clusters of objects:

---
style:
  layers:
    - type: heatmap
      paint:
        heatmap-opacity: 0.5
        heatmap-intensity: 1
        heatmap-radius: 2
  extends: https://styles.trailsta.sh/protomaps-black.json
---
10 Likes
5
6

Yes, the law in Quebec explicitely says that riding a bike on sidewalks is forbidden, but pushing it is legal. After the discussion and for better routing results in the future, we decided to convert all bicycle=no to bicycle=dismount when footway=sidewalk tag is present. A lot of parks and shops are only accessible via a sidewalk for cyclists, so keeping bicycle=no did make some POIs inaccessible.

2 Likes
7

note that bicycle=no does not mean that pushing bicycle is illegal

1 Like
8

I know, but a lot of people understand it as so. There are some places in Quebec where bicycle=no on a sign means even no pushing. There is a notorious park in Montreal where people pushing bikes (dismounted) have been harassed by local residents… Sigh!

9

call that a bold move lol

i believe this is the result of, and being actively discussed in this thread

10

The change to bicycle=dismount in Quebec predates the thread you linked by a few months…

Nevertheless, this is not the topic of this thread

1 Like