Almost two years ago I published a web service that finds suspicious OpenStreetMap (OSM) map changes. You can use the service here and find some more information in previous blog posts. Especially Changeset discussions revealed that they are more or less de facto standard for communication between contributors during map change reviews.

However, when I am inspecting map changes, I sometimes see new contributors using uncommon OSM tags. Therefore I think it could be useful to add an additional assessment parameter to the aforementioned suspicious OSM map changes page. The newly introduced indicator states the matching ratio between the contributed and the most popular OSM tags. This means, if the changeset contributor used many uncommon tags at her/his map changes objects, the matching rate will be low. If the contributor applied many common (“popular”) tags, it results in a high matching rate towards 100%. For the calculation I used Jochen Topf’s taginfo API to get commonly used OSM tags. An API description can be found here. Furthermore I added the average age (in days) of modified and deleted objects. This indicator can be used to see if the contributor edited objects, which have been mapped today (0 days) or exist already for a longer period of time, e.g. 1566 days. The values for the average version numbers are computed in a similar fashion.

Last but not least, the number of the affected contributors of the changeset is calculated. If a contributor only changes objects on which she or he is the latest modifier, this number will be ‘0’. Otherwise the value represents the number of unique mappers whose contributions have been changed. I hope that overall the newly added indicators can be useful for identifying changesets which need a closer look. The suspicious OSM map changes website has also received some style updates. They should help to highlight the most important parameters. I also added the aggregation of the latest changesets for a specific contributor. Guess this could be really useful to see a “big picture” of the individual mapping activities.

The aforementioned service is online here –> “Find Suspicious OpenStreetMap Changesets”

Thanks to maɪˈæmɪ Dennis.

The OSM project still records around 650 new contributors each day (out of almost 5,000 registered members per day). Some countries (such as Belgium or Spain) already provide platforms to coordinate the introduction to OSM for new mappers. Others use special scripts or intense manual work to send the newly registered contributors mails with useful information (Washington or The Netherland). However, oftentimes new contributors make, as expected, beginner-mistakes. Personally, I often detect unconnected ways, wrong tags or rare fictive data. Unfortunately, sometimes (new) members also delete, intentionally or unintentionally, existing map data.

At the end of 2014, many people were anticipating the newly introduced changeset discussions feature. A few months later, I developed a page that finds the latest discussions around the world or in your country. By now, many OSM members use changeset discussions for commenting or questioning map edits of other members.

However, one year ago, almost to the day, I wrote a blog post about a webpage for detecting suspicious OSM edits. In the newly updated version, I would like to combine the aforementioned changeset discussions and comments about suspicious edits to communicate with members in a more direct way. The following image shows the revised webpage.

Furthermore you can request all changesets of a contributor, which have been commented on. The same page can also show all comments written by a selected contributor (with all comments of the particular changeset). I think the last both features are really helpful for keeping control over your own and other changeset discussions. This should also simplify the reviewing process of changesets and map edits.

As mentioned at the beginning of this blog post, some OSM groups send a welcoming e-mail to new contributors. I also saw that some mappers are welcoming new members in Taiwan with a changeset comment and information on their first changeset. Pretty neat stuff if you ask me.

Latest OSM Changeset Discussions: http://resultmaps.neis-one.org/osm-discussions
Find Suspicious OSM Changesets: http://resultmaps.neis-one.org/osm-suspicious

Thanks to maɪˈæmɪ Dennis.