OSMCha is a well known OSM changeset inspection and validation tool. It lets you look at changesets through different lenses. You can filter by individual mappers, geographic locations, mapping teams, and a variety of flags that are automatically applied to changesets, like ‘possible import’, ‘profanity’ and ‘outdated tags’. Using a combination of filters, you can craft your very own feed of changesets that you would like to review. In short, OSMCha is an indispensable tool for anyone interested in what’s being added to OSM in fine detail.

Recently, OSMCha maintainer Wille Marcel added close integration between OSMCha and MapRoulette. OSMCha can now create and maintain Challenges based on incoming changesets that are automatically flagged by OSMCha.

Let’s look at an example.

One of many things OSMCha automatically flags is whenever a changeset contains a change to a place node. Because place nodes represent the name and location of a town, city, village or other settlement, edits to these types of nodes should be fairly uncommon: the name or location of a place usually does not change. It is reasonable for OSMCha to flag these changesets for review by a human, just to make sure the change is OK.

MapRoulette showing a task generated by OSMCha using its 'Edited a place' flag.
MapRoulette showing a task generated by OSMCha using its ‘Edited a place’ flag.

OSMCha creates the Challenge in MapRoulette (see it here) and will continuously feed it with new tasks as it detects and flags changesets containing modifications to a place node. Mappers then have an easy way to quickly verify changes using the MapRoulette workflow—either at random, or start with close to you and work your way through any other nearby tasks.

The link between OSMCha and MapRoulette is a great example of how open source OSM tools can connect and work together to bring the OSM community the best possible tools to keep the map clean and fresh!