- Introduction to OSMCha
- Usage
- FAQ
- How are the changesets presented?
- How can I sign-in into OSMCha?
- Can I view the changesets and use filters without logging into OSMCha?
- How do I logout of OSMCha?
- My changeset has been flagged by a reason, am I doing something wrong?
- Are there keyboard shortcuts in OSMCha?
- What are tags on OSMCha?
- What if I want to change my review for a changeset?
- Can I review my own changesets?
- Frequent error messages
- Changeset views error messages
- Changeset was already checked.
- User can not check their own changeset.
- Changeset is not checked.
- User does not have permission to uncheck this changeset.
- User can not add tags to their own changeset.
- User can not add tags to a changeset checked by another user.
- User can not remove tags from their own changeset.
- User can not remove tags from a changeset checked by another user.
- Changeset views error messages
- References
- Other tools for validation
- Feedback
- Donate
- Trademark notice
OSMCha is short for OpenStreetMap Changeset Analyser. It is a web tool to help visualise and analyse edits made by mappers on OpenStreetMap (OSM). OSMCha was originally written by Wille Marcel in 2015 to validate changesets. After almost 10 years being supported by Mapbox, OSMCha became an OpenStreetMap US charter project in 2023.
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OpenStreetMap is a crowdsourced project, and it is necessary to have user friendly tools for the community, to guide new contributors to make a great map.
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Any given day, around 30,000 changesets containing additions, modifications, and deletions to the data make their way into OSM, which is driven by a strong community.
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With new users signing up on OSM every day, it is likely that the mapping guides/wikis on tagging scheme, general practices are not uniformly followed by every contributor, resulting in accidental edits, and in rare cases intentional vandalism that breaks the map.
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OSMCha is designed to be an integrated tool that can address various validation requirements of the community. OSMCha is also supported by an open source edit recognition project called OSM-Compare which can be used for suggesting manual verification.
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This tool offers advanced filtering options that can help you filter changesets based on various OSM metatags and attributes. (Ex: All changesets with hashtags, user specific changesets, etc.).
Vandalism with respect to OpenStreetMap refers to deliberate acts of destruction or damage to the map data. These include, intentional edits that cause visible breakages on the map and also break other crucial map data such as route relations, boundaries, turn restrictions, land use classification etc.
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Flagged changesetsare changesets that are flagged by OSM-Compare for specific edit behaviour. Like deletion of valid data, incompatible data errors. Example - A swimming pool tagged asnatural=water. -
OSMCha is supported by an edit detection pipeline called OSM-Compare. It is an open collection of compare functions written in Javascript that automatically check for suspicious changes on OSM and pushes them into OSMCha to different categories of identifiable edit behaviour. Currently, there are compare functions in OSM-Compare for flagging deletions of cities, overlap between features, and similar rule based scenarios.
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Any changeset on OSM can be reviewed by the community to confirm the quality of the edit. You can 👍 for edits that do not cause any damage to the map, and 👎 for those that may break map data or is invalid data.
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This data is collected to help improve the compare functions in OSM-Compare project. Thus helping it become more efficient and robust by testing it against a verified database of good and bad changesets.
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Consistent categorisation of changesets also helps to build an open source database for use in ventures related to machine learning or automating the detection process for bad edits instead of writing rule based compare functions for all possible scenarios of bad edits.
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Machine learning based detection methods replace rule based edit detections. This makes it easier for analysis, automates maintenance and has prospects for better detection rates to catch bad edits on OpenStreetMap.
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OSMCha will continue to be an OpenStreetMap validation tool that get feeds from OSM-Compare with constant maintenance, with features towards an easier user experience for validation of edits on OpenStreetMap.
It is important that the reviewer has the necessary information about the changeset and understand the diff of modifications in the OSM data.
For this purpose, OSMCha offers an interface similar to OpenStreetMap but with additional tools such as changeset-map to visualise the edits, information about the mapper, other information related to the changeset and OSM user history that can help the reviewer identify a problematic edits on OSM. For a deep-dive into what a problematic edit is on OSM, please refer to our guide on Validating OpenStreetMap.
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The details panel on OSMCha provides information on the changeset and the mapper.
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In the top right corner of the panel, in blue, yellow and red, number of additions, modifications and deletions of the changeset are presented.
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The details include the username of the mapper, number of changesets the mapper has contributed on OSM, changeset discussion comments and further details like the editor and imagery used in making the edits on OSM.
- When an edit is
detected through a compare function
on OSM-Compare, it is shown on the
Flagged featurestab. The reviewer can click on Map to view the edit on the changeset map or open it directly on JOSM for detailed review.
- There is also a tab that shows all the features whose tags were modified in the changeset. This makes it easy to identify the modifications made in the features without the need of clicking on them one by one.
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Similarly, if there are comments on the changeset on OpenStreetMap, OSMCha presents the discussion under the discussion tab.
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User's can automatically post OSM changeset discussion comments directly from OSMCha. You can define comment templates on your user page, so you will have a base message to send to a user after reviewing the changeset as good or bad. Right after your review, the comment form will be filled with your saved text. We suggest you to communicate with other mappers to alert them of errors, aspects to improve or simply to welcome a new user or praise a good edit.
- More details on the mapper can be found under the
User tab. This gives more context to the reviewer about the user history and their pattern of contribution to OpenStreetMap.
- Changeset-map is a changeset visualiser for OSM. It helps the reviewer understand the edits of a changeset both in terms of geometry and feature properties.
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The reviewer can click on any particular feature edited in that changeset and see the additions, deletions and modifications made to the feature to have an informed decision on quality of the edits.
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Click on map from
Flagged features taband visualise it in changeset map.
- The reviewer can also change the background map on the changeset-map by
toggling through the map style in
Map controlstab.
- Open the changeset in a preferred editor or a preferred tool to inspect the changeset.
- If you come across a changeset on OSM while browsing through the history tab or a particular user’s changeset, it is sometimes necessary to see the changes that happened in a changeset visually.
- In these cases, you can copy the changeset ID and open it in OSMCha for visualisation and easily spotting errors in a changeset.
The Filters tab on OSMCha provides a variety of search parameters to fetch a specific list of changesets the reviewer is interested in. One can filter changesets based on a date range, new mapper edits, mass deletions, text in the source field, location, editor used, etc.
Hot project edits are a specific example for which a changeset comment with the associated hashtag can be used to retrieve all the changesets contributed for the task.
The history tab on OpenStreetMap offers a very basic area based retrieval of changesets. It allows a user to zoom in to a specific area on the map and all the changesets in that area are shown on the sidebar in the order of newest first. OSMCha filters expands this feature with much more metadata based search.
These include:
- Words in a changeset comment or changeset comment used by the mapper, for example:
#hotosm-project#MissingMaps - Changeset date based on the time the edits were uploaded on OpenStreetMap
- Number of features added, modified and deleted in a changeset
- Changeset location using the Bbox or the Location filter
- Changesets that are flagged by compare functions for edit behaviour through reason feed from OSM-Compare
- Source or imagery mentioned in a changeset by the mapper
- Specific editor based search
Null island edits
- New mappers tend to add fictional data at 0, 0 coordinates as OpenStreetMap by default opens at these coordinates. Mappers being new, tend to test map and add non existent data due to lack of practice and knowledge of the workflow involved.
Edit count based search
- One can filter changesets based on mass additions, mass modifications, mass deletions and the number of edits made in a changeset.
Using multiple filters on OSMCha
- Local reviewers on OpenStreetMap maybe interested on changesets by searching for changesets based more than 1 condition
- Ex: iD editor changesets that have deleted a lot of features
- Ex: Mass additions of data by new mappers
Filtering by other metadata
Since August 2020, OSMCha is registering all arbitrary tags added to the changesets and it is possible to filter using that information. Scroll to the bottom of the filters page to see the "Other metadata field". For example, you can filter changesets by the hashtags information with hashtags=value.
It is also possible to filter numeric values by setting a minimum or a maximum threshold. For example, with changesets_count__max=50, you will get the changesets created by users that had created less than 50 changesets (that information is available only to changesets created by iD editor). Add __max or __min after any tag name that the value can be a number.
If you want to filter by the presence of a tag use key=*, for example locale=* to find changesets with a locale tag and any value.
It's possible to combine multiple metadata filters by separating the key=value statements with a comma.
OSMCha allows a logged-in user to save a filter template with custom search parameters and a personalized name. There is no limit on how many filter templates can be saved per user nor with the number of custom parameters that can be set in a filter template.
To save a filter, start setting your desired filter parameters, then click on the Save button on the top of the screen, give a name to it and press the Confirm Save button. The filter will be saved and applied, so the sidebar will update with the results. If you want to change something in your filter later, repeat those steps.
Saved filters are listed on the dropdown menu on the left side of the filters page.
They are available also in the user page which can be accessed by clicking on your OSM username beside the OSMCha icon on the sidebar. Any saved filter can be loaded to retrieve search results, shared with a permalink, removed from the saved list or be used to setup an RSS.
OSMCha saves these filters with a unique identifier code. Here is a filter example - https://osmcha.org/filters?aoi=71247014-abbf-4253-8093-2a2afdda4169.
Each saved filter has an RSS feed to update whenever a new changeset comes into the custom filter. A real life application would be to get instant notifications for all edits in the area you are currently surveying.
Here is an RSS feed for the filter we have setup in the above section - https://osmcha.org/api/v1/aoi/71247014-abbf-4253-8093-2a2afdda4169/changesets/feed/.
Any third party RSS client can be used to push instant personal notifications for the changesets that have come into your saved filters at set time intervals.
The user page contains some details like your username and ids, your Review Comments Template and your Saved Filters.
In the Review Comments Template you can set a message template to use in the changeset comments. That way, after you review a changeset, the comment template will be loaded in the discussions tab and you can complement the text or just post the message.
Finally, in the Saved Filters section you can manage your filters, load them and get it's RSS link.
OSMCha reads all changesets from OpenStreetMap. By default they are presented in the order of the newest first based on the filters applied by the OSMCha reviewer.
The list of changesets are presented on the sidebar.
You can select the changeset from the changeset review panel and can view the edits associated to it using the changeset map that appears on the right hand side.
You can sign-in on OSMCha using their OpenStreetMap account. On clicking on sign-in, a window (like the one below) appears, click on Grant Access and you will be singed-in on OSMCha.
No, OSMCha requires a sign in with your OpenStreetMap account in order so see changesets.
After the authentication, the sign-in button on OSMCha shows your OpenStreetMap username. When you click on your username, a dropdown appears, by clicking on the logout button you can sign-out of OSMCha.
No, not at all! These changesets are automatically flagged by OSM-Compare for specific edit behaviour. We are working towards making this detection better over time.
The rule based detectors in OSM-Compare are inefficient in understanding context of an edit, place and mapping activity. This is the disadvantage and reason that these detections are false positives 80% of the time, based on the compare function written.
For example, a place deleted compare function flags an experienced mapper's changeset even if he/she has deleted a fake city previously added by another user. This context is unavailable to the rule based detector for better analysis.
Yes. Keyboard shortcuts on OSMCha help the reviewer to go through a list of changesets quickly. Here are the available shortcuts:
| Description | Shortcut |
|---|---|
| Navigating changeset list | |
| Go to previous changeset (in the changeset list) | ↑ |
| Go to next changeset (in the changeset list) | ↓ or → |
| Refresh changeset list | R |
| Changeset detail view | |
| Open changeset in JOSM | J |
| Open changeset in iD | I |
| Open changeset in OSM | O |
| Open changeset in Achavi | V |
| Open user profile in HDYC | H |
| Open changeset in Level0 | L |
| Review changeset as Good | G |
| Review changeset as Bad | B |
| Undo or clear changeset review | U or C |
| Filter edits of the current changeset's user | A |
| Changeset panels | |
| Toggle Changeset details | 1 |
| Toggle Flagged features | 2 |
| Toggle Tag Changes | 3 |
| Toggle Geometry Changes | 4 |
| Toggle Other Features | 5 |
| Toggle Changeset discussions | 6 |
| Toggle User profile | 7 |
| Toggle Map controls | 8 |
| Other | |
| Toggle Filters page | \ |
| Show this Guide page | ? or / |
The button Tags will only appear when you review a changeset good or bad, but it's recommended and essentially used to describe the details of the changeset that was found to be bad. Here are the different tags that can be used:
- Severity: Critical, High or Low, to estimate how bad do these edits on a changeset affect OpenStreetMap data
- Unresolved: To input action taken by the you (reviewer) on a changeset. It is unresolved when the you (reviewer) have commented on the changeset to inform the mapper for corrections or no action has been taken by the you (reviewer) to correct the map data.
- Intent: Intentional or Unintentional to capture the intent of the user. This is contextual information subjective to the edits and users.
- DWG: When a changeset needs to be reported to the Data Working Group
Yes, it is possible to change the review for a changeset from Good to Bad or
vise versa. You can also unreview a changeset by clicking on the 'x' beside your
username on the top right corner button.
No, you cannot review your own changesets, but you can view your changesets.
This is raised when someone tries to check a changeset that was already checked
This is raised when someone tries to check a changeset that was created by him/her
This is raised when someone tries to uncheck a changeset that is not checked
This is raised when someone tries to uncheck a changeset that another user checked
This is raised when someone tries to add tags to their own changesets
This is raised when someone tries to add tags to a changeset reviewed by someone else.
This is raised when someone tries to remove tags from their own changeset.
This is raised when someone tries to remove tags in a changeset that are added by the other users.
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Wikis
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Related Projects
- MapRoulette
- HDYC
- WHODIDIT
- Who’s That
- Result Maps
- Missing Maps
- OSM user stats
- OSM deep history
- OSM History viewer
- OSM inspector
- OSMOSE
- Overpass
- To file bugs, feature requests on OSMCha - please file issues at https://github.com/osmcha/osmcha-frontend/issues
- To file bugs, feature requests on Changeset map - please file issues at https://github.com/osmlab/changeset-map/issues
Support OSMCha's hosting and development by making a donation: https://openstreetmap.app.neoncrm.com/forms/osmcha.
OpenStreetMap (OSM) is a trademark of the OpenStreetMap Foundation, and is used with their permission. OSMCha is not endorsed by or affiliated with the OpenStreetMap Foundation.