OpenStreetMap

Reviewing recent changes in your area with OSMCha

Posted by manoharuss on 7 April 2017 in English (English)

It is always interesting to review the latest map edits in your local area. It can be fun to send a welcome message to a new contributor or track changes to a neighbourhood that a fellow mapper has surveyed. It's an opportunity to both learn from an experienced contributor as well as teach someone new a helpful tip to make mapping more engaging. In a more rare case, these tools can help investigate some missing data or suspicous mapping activity.

The OSM Changeset Analyzer (OSMCHA) tool by Wille Marcel has a powerful interface to filter changesets in your area and flag any suspiscous changesets for further action.

Here's how you can start using OSMCha in your area:

Step 1 : Understanding and using Filters in OSMCha

OSMCha

image

Currently available filters in OSMCha

Introduction to filters

  • Date fields

    • These date fields are based on changeset closed time as on OSM. We can use date range to narrow down changesets (yesterday, last week)
  • Creations, Modifications and Deletions

    • This is a simple count of type of edits in a changeset
  • A changeset is suspicious when the changeset is flagged by one of the reasons seen below. These are compare functions that flag a certain type of edits. I will go into more details about how compare functions work in OSMCha and how we can use them to flag specific edits. This has to be an another diary post.

  • White-list - When you login into OSMCha using your OSM credentials, OSMCha creates a very basic profile that consists a list of changesets from OSM users you wish to not see in your search. This is a personal custom list for each OSMCha user/reviewer. You can add a user to the white-list when you are in that user's changeset.

  • BBOX - This filter allows to easily give an area of interest we would like to validate. In this case, you can zoom into your particular neighborhood and OSMCha retrieves only changesets whose bbox falls on the area you have given.

These filters give a lot of freedom and flexibility to narrow specific type of changesets we would like to retrieve from a specific area. In OSM one can already use the History tab to see the changesets that overlap with the area on the map but OSMCha adds a lot of filters to this idea to assist the reviewer.

Step 2: Validating your neighborhood

bbox2

Using bbox filter to select area of interest

When we click the search button, OSMCha presents us with a list of changesets that it thinks fit into our search criteria. An embed version of changeset-map shows geometric and feature tags of edits on the map.

Along with the contextual information where the edits are on the map, geometric edits to the feature, you can also click on the features in the changeset map touched by that changeset to see previous version feature tags and current version feature tags.

Did you try using OSMCha? What worked, and what did you not like? Let us know in the comments below.

Feedback

If you come across a bug you would like to give feedback on, use OSMCha-django repository to file an issue. An issue with overlap of global changesets when using bbox filter in OSMCha has been already raised in my previous diary post. We are working on to best resolve this issue.

If you would like improve detection of a particular type of feature edit, check out our OSM-compare repository and open an issue.

Comment from Albert Moreau on 11 April 2017 at 12:24

I like this post.

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