# Photogrammetry classification

**URL:** <https://community.cesium.com/t/photogrammetry-classification/28910>\
**Category:** 3D Tiles\
**Created:** [December 25, 2023, 8:17am UTC](https://community.cesium.com/t/photogrammetry-classification/28910 "2023-12-25T08:17:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![naste4kina](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/naste4kina/32/14037_2.png) [@naste4kina](https://community.cesium.com/u/naste4kina)\
**Post date:** [December 25, 2023, 8:17am UTC](https://community.cesium.com/t/photogrammetry-classification/28910/1 "2023-12-25T08:17:09Z")

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Hi everyone!  
May be you can help me?  
I found these example [Cesium Sandcastle](https://sandcastle.cesium.com/?src=3D%20Tiles%20Next%20Photogrammetry%20Classification.html)  
and i’m wondering what program was used to perform photogrammetric classification when creating 3D Tiles, and how can the result be used?

Thank you in advance  
Anastasia

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**Author:** ![Marco13](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/marco13/32/2757_2.png) [@Marco13](https://community.cesium.com/u/Marco13)\
**Post date:** [January 12, 2024, 2:16pm UTC](https://community.cesium.com/t/photogrammetry-classification/28910/2 "2024-01-12T14:16:05Z")

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Sorry for the late response here.

The data in this example was provided by external contributors. We do not know the details about how the classification itself was performed. (It may very well have been a manual process).

The actual classification information is stored in the tile glTF tile content: It uses the `EXT_mesh_features` glTF extension to store “feature IDs” - specifically: Each point on the surface for the mesh receives an ID, using a [feature ID texture](https://github.com/CesiumGS/glTF/tree/3d-tiles-next/extensions/2.0/Vendor/EXT_mesh_features#feature-id-by-texture-coordinates).

(These feature IDs are associated with metadata, using the [`EXT_structural_metadata`](https://github.com/CesiumGS/glTF/tree/3d-tiles-next/extensions/2.0/Vendor/EXT_structural_metadata) extension. It stores the color and the name for each component type (i.e. for each ID) using a Property Table)