> For the complete documentation index, see [llms.txt](https://docs.imerit.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.imerit.net/3d-multi-sensor-fusion/labeling/category-schema.md).

# Category Schema

## Ontologies

A Category Schema is defined as the project ontology with its classes and their attributes and associations.

<div data-with-frame="true"><figure><img src="https://3895963154-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTcOUG6rfWxqGM0N4db2P%2Fuploads%2F2JTjzVeDk5GlmMtvUruQ%2Fimage.png?alt=media&amp;token=aeeefb9e-8484-419c-ac9b-61d3be930397" alt=""><figcaption></figcaption></figure></div>

Once the ontology is created under the Category Schema, it will appear in the following way on the tool:

<div data-with-frame="true"><figure><img src="https://3895963154-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTcOUG6rfWxqGM0N4db2P%2Fuploads%2FBSY8bRNvGmGUs4hj98Lw%2Fimage.png?alt=media&amp;token=989566b8-3f13-406c-bb41-10fa62506feb" alt=""><figcaption></figcaption></figure></div>

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To create the ontology click on Add Category

<div data-with-frame="true"><figure><img src="https://3895963154-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTcOUG6rfWxqGM0N4db2P%2Fuploads%2FpLFoF1WoNl8jxGu89v9e%2Fimage.png?alt=media&amp;token=6b50867d-1ef3-49ee-bc66-1931400f7511" alt=""><figcaption></figcaption></figure></div>

### PCT (Class Level)

To add a new class/category\
For more info - [goto](#pct-class-level)

### Classifications (Task or Sequence Level)

Boolean

Single-Select Dropdown

Multi-select Dropdown

Text

For more info - [goto](/3d-multi-sensor-fusion/labeling/category-schema/classifications.md)

### Relations (Relationships of Objects)

Many

For more info - [goto](/3d-multi-sensor-fusion/labeling/category-schema/relations.md)