# OSMCha

> Web application for reviewing changes to OpenStreetMap

**Wikidata**: [Q100364318](https://www.wikidata.org/wiki/Q100364318)  
**Source**: https://4ort.xyz/entity/osmcha

## Summary
OSMCha (OpenStreetMap Changeset Analyzer) is a web application designed for reviewing changes made to OpenStreetMap. It functions as an OpenStreetMap monitoring and changeset review tool, primarily used for quality control and countervandalism within the mapping project.

## Key Facts
*   OSMCha was first conceived in September 2015.
*   It is developed by Wille Marcel.
*   Its primary uses include countervandalism and quality control for OpenStreetMap changesets.
*   OSMCha is classified as free software and is written in Python.
*   The application's front end is licensed under the ISC license, its back end under the 2-clause BSD License, and its Python package under the GNU General Public License, version 3.0.
*   Mapbox was a funder and distributor until February 17, 2023.
*   OpenStreetMap U.S. became its fiscal host from February 17, 2023, and will own it from January 15, 2026.
*   The latest version provided is 3.0.2, released on June 5, 2018.

## FAQs
### Q: What is OSMCha?
A: OSMCha, which stands for OpenStreetMap Changeset Analyzer, is a web application used for reviewing changes made to OpenStreetMap. It serves as a dedicated tool for monitoring and analyzing OpenStreetMap changesets.

### Q: What is OSMCha used for?
A: OSMCha is primarily used for countervandalism and quality control within OpenStreetMap. It helps users review edits to identify and address potential issues, ensuring the accuracy and reliability of the map data.

### Q: Who developed and funds OSMCha?
A: OSMCha was developed by Wille Marcel. It has received funding from Mapbox and is fiscally hosted by OpenStreetMap U.S., which is also slated to become its owner from January 15, 2026.

### Q: What programming language is OSMCha written in?
A: OSMCha is primarily written in Python, a general-purpose programming language.

### Q: Is OSMCha free software?
A: Yes, OSMCha is free software. Its various components are distributed under different free licenses, including the ISC license for the front end, the 2-clause BSD License for the back end, and the GNU General Public License, version 3.0, for its Python package.

## Why It Matters
OSMCha plays a critical role in maintaining the integrity and quality of OpenStreetMap, a vital global collaborative mapping project. By providing a specialized web application for reviewing changes, it directly addresses the ongoing challenges of countervandalism and ensures robust quality control for the vast number of edits contributed by mappers worldwide. Its function as an OpenStreetMap monitoring and changeset review tool is indispensable for identifying and rectifying problematic contributions, thereby safeguarding the accuracy and trustworthiness of the map data. The support and funding from organizations like Mapbox and OpenStreetMap U.S. underscore its recognized importance within the OpenStreetMap ecosystem, highlighting a collective commitment to data validation, community oversight, and fostering a healthy mapping environment.

## Notable For
*   Its specialized function as a web application dedicated to reviewing OpenStreetMap changesets for countervandalism and quality control.
*   Its multi-component licensing structure, with different parts (front end, back end, Python package) released under distinct free software licenses.
*   Its evolution of organizational support, transitioning from being funded by Mapbox to being fiscally hosted and eventually owned by OpenStreetMap U.S.
*   Its classification as an "OpenStreetMap welcoming tool," indicating its broader role in community engagement and fostering positive contributions.

## Body

### Overview
OSMCha (OpenStreetMap Changeset Analyzer) is a web application designed for reviewing changes to OpenStreetMap. It serves as an OpenStreetMap monitoring tool and an OpenStreetMap Changeset review tool, used for countervandalism and quality control. It is also classified as an OpenStreetMap welcoming tool.

### Purpose and Use
OSMCha's primary `use` cases are:
*   Countervandalism
*   Quality control
It `uses` OpenStreetMap changesets as its core data.

### Development and Funding
*   **Developer**: Wille Marcel
*   **Inception**: September 2015
*   **Funder**: Mapbox
*   **Affiliation**:
    *   OpenStreetMap U.S. (fiscal host from 2023-02-17 to 2026-01-15)
    *   OpenStreetMap U.S. (OpenStreetMap U.S. charter project from 2023-02-17 to 2026-01-15)
*   **Owned by**: OpenStreetMap U.S. (from 2026-01-15)
*   **Distributed by**:
    *   Mapbox (until 2023-02-17, started 2016)
    *   OpenStreetMap U.S. (from 2026-01-15)
*   **Contributor to the creative work or subject**: Mapbox

### Technical Details
*   **Programming language**: Python
*   **License**:
    *   ISC license (applies to front end)
    *   GNU General Public License, version 3.0 (applies to Python package)
    *   2-clause BSD License (applies to back end)
*   **Source code repository URL**:
    *   `https://github.com/mapbox/osmcha-frontend/` (front end)
    *   `https://github.com/willemarcel/osmcha-django` (back end, application programming interface)
    *   `https://github.com/OSMCha/osmcha` (Python package)
*   **Issue tracker URL**: `https://github.com/osmcha/osmcha-frontend/issues`
*   **Copyright status**: copyrighted

### Versions
OSMCha has undergone several releases, including:
*   v2.6.0 (released 2017-12-27)
*   v2.7.0 (released 2018-02-01)
*   v2.7.1 (released 2018-02-07)
*   v2.7.2 (released 2018-03-13)
*   v2.7.3 (released 2018-03-26)
*   v2.7.4 (released 2018-04-02)
*   v2.7.5 (released 2018-05-22)
*   v3.0.0 (released 2018-05-31)
*   v3.0.1 (released 2018-06-05)
*   v3.0.2 (released 2018-06-05)

### Classification
OSMCha is an `instance_of`:
*   Free software
*   Software project
*   OpenStreetMap monitoring tool
*   OpenStreetMap Changeset review tool
*   Web map application
*   OpenStreetMap welcoming tool
*   OpenStreetMap U.S. charter project (from 2023-02-17 to 2026-01-15)
It is `related` to:
*   Free software
*   Python

### Aliases and Websites
*   **Aliases**: OpenStreetMap Changeset Analyzer, OSM Changeset Analyzer
*   **Websites**:
    *   `https://osmcha.mapbox.com/` (English, started 2016)
    *   `https://osmcha.org/` (preferred, English, started 2020)

### Documentation and Resources
*   **Described at URL**: `https://openstreetmap.us/our-work/charter-projects/osmcha/` (English, described as "The ultimate OpenStreetMap validator")
*   **Described by source**: OpenStreetMap Wiki (`https://wiki.openstreetmap.org/wiki/OSMCha`)
*   **Collection**: OSM Apps Catalog

## References

1. [Source](https://wiki.openstreetmap.org/wiki/Welcome_tool/OSMCha)
2. [Source](https://openstreetmap.us/news/2023/02/OSMCha_Announcement/)
3. [Source](https://openstreetmap.us/news/2026/01/maproulette-and-osmcha-become-programs/)
4. [Source](https://api.github.com/repos/mapbox/osmcha-frontend)
5. [Source](https://github.com/OSMCha/osmcha)
6. [Source](https://github.com/OSMCha/osmcha-django)
7. [Release 2.6.0. 2017](https://github.com/willemarcel/osmcha-django/releases/tag/v2.6.0)
8. [Release 2.7.0. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v2.7.0)
9. [Release 2.7.1. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v2.7.1)
10. [Release 2.7.2. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v2.7.2)
11. [Release 2.7.3. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v2.7.3)
12. [Release 2.7.4. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v2.7.4)
13. [Release 2.7.5. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v2.7.5)
14. [Release 3.0.0. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v3.0.0)
15. [Release 3.0.1. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v3.0.1)
16. [Release 3.0.2. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v3.0.2)
17. [Release 3.0.3. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v3.0.3)
18. [Release 3.0.4. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v3.0.4)
19. [Release 4.0.0. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v4.0.0)
20. [Release 4.1.0. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v4.1.0)
21. [Release 4.1.1. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v4.1.1)
22. [Release 4.2.0. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v4.2.0)
23. [Release 4.2.1. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v4.2.1)
24. [Release 4.2.2. 2018](https://github.com/willemarcel/osmcha-django/releases/tag/v4.2.2)
25. [Release 4.2.3. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.2.3)
26. [Release 4.3.0. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.0)
27. [Release 4.3.1. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.1)
28. [Release 4.3.2. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.2)
29. [Release 4.3.3. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.3)
30. [Release 4.3.4. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.4)
31. [Release 4.3.5. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.5)
32. [Release 4.3.6. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.6)
33. [Release 4.3.7. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.7)
34. [Release 4.3.8. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.3.8)
35. [Release 4.4.0. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.4.0)
36. [Release 4.4.1. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.4.1)
37. [Release 4.4.2. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.4.2)
38. [Release 4.4.3. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.4.3)
39. [Release 4.4.4. 2019](https://github.com/willemarcel/osmcha-django/releases/tag/v4.4.4)
40. [Release 4.5.0. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.5.0)
41. [Release 4.5.1. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.5.1)
42. [Release 4.5.2. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.5.2)
43. [Release 4.6.0. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.6.0)
44. [Release 4.6.1. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.6.1)
45. [Release 4.6.2. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.6.2)
46. [Release 4.7.0. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.7.0)
47. [Release 4.7.1. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.7.1)
48. [Release 4.8.0. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.8.0)
49. [Release 4.9.0. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.9.0)
50. [Release 4.9.1. 2020](https://github.com/willemarcel/osmcha-django/releases/tag/v4.9.1)