Correcting Data, or Mappers?

This unit will discuss when to mark tasks as validated or when to invalidate and how to approach OSM contributors with guidance.

Items to Read

LearnOSM: Humanitarian Mapping

During the Nepal Activation there was a desire to both give thanks and give a bit more guidance to the incredible amount of new mappers. The Humanitarian Mapping module in LearnOSM started as a letter specifically about the Nepal Activation and has since been more generalized, it is a good example of the type of communication HOT expects of Validation Activators.

Validation Best Practices

Tasking Manager Validation

There is a bit of a process to decide if a task on the OSM Tasking Manager should be validated or not. The TM/Validation wiki-page gives a suggested process for handling single-tile validation.

Vandalism

What if you suspect a mapper is intentionally damaging the map; this is important business of HOT, pay attention! Failing to act in this situation could exclude you from legal protections if the data or map usage results in harm to first responders or aid workers on the ground (see the Community Care course Unit 2 lesson on legal risks).

Usually, what initially looks like it might be vandalism is someone just very new and confused with editing. The OpenStreetMap wiki-page on Vandalism has guidelines for how to recognize and what to do in case of actual vandalism, following those recommendations and informing the Activation Lead as soon as vandalism is suspected, will reduce any individual liability.

Task Markup

If a task either clearly is done, or clearly needs to be invalidated, then a simple comment should be enough. The next lesson will discuss best practices for communicating with mappers.

In general when you mark a task a valid, although it is not required, please give them some encouragement; or if you corrected a few things yourself gently let them know with a message such as "thanks for contributing, I added a few missing buildings, but for the most part - great job!"

If the task needs to be invalidated, your comment should explain why, example "I am invalidating this task, the instructions ask for roads and buildings, but only roads are complete."

Review the Tasking Manager wiki-page on validation for guidance.

Large Area Validation

Part of the Activation Conclusion is to review the entire area of interest as a whole; also with time try to do this throughout the Activation. There are a variety of 'techniques' to doing large area validation/quality assurance, a good description and discussion can be found in Lisa Marie Owen's OSM Diary Post. In general you will:

Need a tool such as JOSM that can handle the amount of data in the AOI, or have a process for 'breaking into manageable chunks'. This may be where you can use a tool like OSM Inspector, to find the errors before getting out the editor.
Need a tool such as JOSM pre-sets for selecting problem features, especially one that can select/fix many at once.
Need a tool that can upload the data into OpenStreetMap in 'batches', the last thing you want is to correct a lot of data and not be able to upload it; when doing very large uploads, explore options such as those in JOSM that allow the process to happen in batches or individual features.

Review

Choose the appropriate response to the following scenario:

You are validating a single task and the instructions call for only buildings to be mapped, the task is marked complete with the following comment "Done, except cloud cover in southeast corner."

Upon inspection of the data in JOSM you find that another imagery layer shows only a few missing buildings, the rest of the buildings are mapped well.

How would you handle this validation?

Invalidate the task with the comment "Buildings Missing."
Map the missing buildings and validate the task with the comment "I used another imagery layer to finish the buildings, otherwise great work."
Mark the task validated with the comment "Good job".

People reading this material for credit on the HOT Courses website should share their answer in the #courses slack channel on HOT's Slack ( Request Invite ) If anyone has any question about the correct answer to a Review question, please ask in the #courses channel of HOT's Slack.

Helping the Mapper

When to Reach Out

Anytime you think a contributor needs guidance, you should reach out. If they are new and making typical mistakes like not squaring buildings, making that comment on Tasking Manager may not be enough to reach them. And even veteran mappers sometimes don't understand the instructions or are unfamiliar with the tagging schemes being used. The first step in determining whether and how to make contact is by looking at their profile, in the Tasking Manager click the user's name and you will see their complete history of contributions through projects; this is not their complete OpenStreetMap history but shows the basics stats like how long they have been contributing and how many changesets they have submitted. If you click the link to the user's OSM profile, some of the things you can learn potentially a lot more if they've added additional information.

Contacting Directly

If the mapper isn't responding or changing behavior via comments or invalidating on the Tasking Manager, you may need to try and reach them directly. If there is no contact information on their OSM Profile, you can use the messaging system in OpenStreetMap to email them; there is an explanation on the wiki-page on OSM contact channels.

Urgent Contact

If there is an urgency in trying to reach a mapper - because of potential vandalism or timeliness to the Activation objectives, make sure to inform the Activation Lead(s), they may know other ways to contact the mapper or if it needs to be escalated to the OpenStreetMap Foundation Data Working Group, they will need to be involved.

Review

It is true that HOT requires and collects email addresses of every mapper that uses the Tasking Manager?

True
False

Correcting Data, or Mappers?