Multiple Classification

You can mark certain classification classes as being "Multiple". When you do so, those classifications can be answered more than once by annotators.

Set Up Multiple Classifications

From your project's dashboard, go to Settings -> Category Schema. From the Add Category dropdown, add a classification to your project. Click on it to expand it, and enable the Multiple toggle:

This classification will be marked as multiple, and annotators will be able to answer it more than once.

Answer Multiple Classifications

When labeling, if a classification has been marked as multiple, it will have a "+" sign next to it. Click on it to answer the classification more than once. You can click on the trash can next to a classification to remove it.

Importing Multiple Classifications

Here is a sample import for importing multiple classifications:

[
  {
    "data": "https://angohub-public-assets.s3.eu-central-1.amazonaws.com/6514e5c0-a3f1-4fd7-818f-8b1a2826107a.jpg",
    "classifications": [
      {
        "schemaId": "0e7e61deb89204036819943",
        "title": "Color",
        "answer": "Black"
      },
      {
        "schemaId": "0e7e61deb89204036819943",
        "title": "Color",
        "answer": "White"
      },
      {
        "schemaId": "0e7e61deb89204036819943",
        "title": "Color",
        "answer": "Red"
      }
    ]
  }
]

This import will provide this result:

Importing Frame-Specific Multiple Classifications

When you have a video, or an asset with multiple pages/frames, you may need to have frame-specific classifications, that is, a unique answer for each frame. You can combine frame-specific classifications and multiple classifications to have multiple, frame-specific classifications.

Here is a sample import for a video, with multiple frame-specific annotations:

[
  {
    "data": "https://angohub-public-assets.s3.eu-central-1.amazonaws.com/10c65b5f-702d-419c-83b9-bdc526008fb6.mp4",
    "classifications": [
      {
        "schemaId": "1331ff47f975d7d06e8e053",
        "objectId": "object_1",
        "tool": "radio",
        "title": "Multiple Radio",
        "answer": "1",
        "page": 1
      },
      {
        "schemaId": "1331ff47f975d7d06e8e053",
        "objectId": "object_2",
        "tool": "radio",
        "title": "Multiple Radio",
        "answer": "2",
        "page": 4
      },
      {
        "schemaId": "1331ff47f975d7d06e8e053",
        "objectId": "object_1",
        "tool": "radio",
        "title": "Multiple Radio",
        "answer": "2",
        "page": 20
      },
      {
        "schemaId": "1331ff47f975d7d06e8e053",
        "objectId": "object_2",
        "tool": "radio",
        "title": "Multiple Radio",
        "answer": "1",
        "page": 15
      }
    ]
  }
]

In the above example, we use object IDs to be able to edit different answers to the same classification.

We have only one classification class, called Multiple Radio.

On Page 1 the classification is answered once with the answer 1. On page 4, we add a new answer, and we answer with 2.

Then, on page 20, we change our first answer from 1 to 2. We are able to do this because we used the same object ID. Hub, then, knows not to add a new answer but to change the one that already exists.

On page 15, we do the same and this time change our second answer from 2 to 1.

From the import, it is not currently possible to remove/reset answers, as well as stopping interpolation of an answer.

What this means is that once you set an answer, if you do not change it until the end of the video, will remain the same for all frames until the end.

Preventing Users from Deleting Multiple Classification Answers

If you have imported pre-labels containing multiple classification answers, and you wish to prevent users from deleting them, you may lock the