Creating MapRoulette mission from a Footprint project from MapSwipe

[frozenhelium]

Get the data from MapSwipe

• Goto Data page in the Mapswipe Website
• Find the project you're looking for. (You can use search and filter functionality)
• Go to the Project details page by clicking on the project
• In the Download the data section, you can find the necessary data under Aggregated Results (with Geometry)
• Download the data using the Download button. You'll get a gzipped GeoJSON file (.geojson.gz)
• You can unzip the downloaded data to get the GeoJSON file.
• The data structure of the GeoJSON should look like:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "0_count": 0,
        "1_count": 4,
        "2_count": 0,
        "3_count": 0,
        "total_count": 4,
        "0_share": 0,
        "1_share": 1,
        "2_share": 0,
        "3_share": 0,
        "agreement": 1
        // ...other properties are hidden
      },
      "geometry": {
        // ...properties are hidden
      }
    }
  ]
  // ...other properties are hidden
}

MapSwipe Data Page

Project Download Section

Understanding the feature properties

The properties in the feature are generated from the responses of the MapSwipe app users of the project.

A footprint project typically has 3 options that app user can choose from.

• Yes (Represented by 1)
• No (Represented by 0)
• Not Sure (Represented by 2)

However, these options can be customized while creating the project. The managers can customize both the label and the value.

Optionally, we can have sub-options for each option.

We have 4 different type of properties that we're interested

<value>_count

These type of properties represent the number of users who responded with <value>
For exampe:
"0_count": 0 means that 0 users selected No for this feature
"1_count": 4 means that 4 users selected Yes for this feature

total_count

This property represents the total number of users who responded

<value>_share

These type of properties represent the ratio of "Number of users who responded with <value>" to "Total number of users who responded"
i.e. "0_share" = "0_count" / "total_count"

agreement

This property is a statistical measure for assessing the reliability of agreement between a fixed number of raters when assigning categorical ratings to a number of items or classifying items.
More details can be found here

Footprint Options

Footprint Suboptions

Clean / Transfrom the data

Filtering

The export contains all the features initially selected while creating the project. But, we are only interested in a subset of the features. To extract only the features of our interest, we can filter the features using the above mentioned properties.

For example: Consider a situation where we want dataset that contains all results where at least 35% of users submitted a Yes or Not Sure classification.

const geoJson = await loadFromFile('./agg_results_project_id_geom.geojson');
const filteredGeoJson = {
  ...geoJson,
  features: geoJson.features.filter(
    (feature) => {
      const {
        properties: {
          1_share,
          2_share,
        }
      } = feature;

      return (1_share + 2_share) > 0.35;
    }
  ),
}

Grouping

The export might contain a lot of features even after the filtering. It is good to group the features so that we have lesser numer of tasks in MapRoulette.

There are various methods of grouping:

1. Clustering features by proximity
2. Splitting the area into tiles

We can use GIS software to implement the grouping.

Create a MapRoulette Challenge

Once you have the GeoJSON after the filtering and grouping, you're now ready to create a mission in MapRoullete.

Upload the GeoJSON

Go to Create & Manage page in MapRoulette and open a project where you want to create the challenge (mission).

Click on Add Challenge and fill in the details.

Select I want to upload a GeoJSON file under Location of your task data. After that, you should be able to upload the GeoJSON
Note: If you get the error saying
GeoJSON error: Polygons and MultiPolygons should follow the right hand rule
you can use geojson-rewind to fix the issue

Fill in the other details as well and click on Finish button to complete the process.

It will start building the tasks for the challenge. Once completed, you can proceed to next step

Navigating to "Create & Manage" page	Adding a Challenge
Adding the GeoJSON	Task building progress

Start the MapRoulette Challenge

• Open the project you want to map and click on Start Challenge
• Click Edit button in the Completion section. You should be redirected to OpenStreenMap iD editor
• Select the imagery used for the project from Background
• Check if the feature in the area are correctly mapped
• Correct or delete the feature if needed
• Save and upload your edits to OpenStreetMap
• If you made any correction or deleted any feature, please mark I fixed it!
  • A pop-up will appear. Describe what was wrong with the buildings you corrected in the comment box of the pop-up
• If no correction or deletion was needed, please mark as Not an issue

Starting a new Challenge	Editing in iD editor
Setting the background imagery

[Jorieke]

Great write-up!