A Question About the Data Format in Annotations

[miles0428]

In MediaPipe by Google, I think each landmark is in 3D space, including the x-axis, y-axis, and depth. However, I found that each point in the hand_landmarks data format is in 2D space. I assume that the depth information for each point has been deprecated. I also wonder why the depth information was removed in this project. Is it considered trivial, or was it done for a specific reason?

"04c49801-1101-4b4e-82d0-d4607cd01df0": {
    "bboxes": [
        [0.0694444444, 0.3104166667, 0.2666666667, 0.2640625],
        [0.5993055556, 0.2875, 0.2569444444, 0.2760416667]
    ],
    "labels": [
        "thumb_index2",
        "thumb_index2"
    ],
    "united_bbox": [
        [0.0694444444, 0.2875, 0.7868055556, 0.2869791667]
    ],
    "united_label": [
        "thumb_index2"
    ],
    "user_id": "2fe6a9156ff8ca27fbce8ada318c592b",
    "hand_landmarks": [
            [
                [0.37233507701702123, 0.5935673528948108],
                [0.3997604810145188, 0.5925499847441514],
                ...
            ],
            [
                [0.37388438145820907, 0.47547576284667353],
                [0.39460467775730607, 0.4698847093520443],
                ...
            ]
        ]
    "meta": {
        "age": [24.41],
        "gender": ["female"],
        "race": ["White"]
    }