{
  "id": 585695,
  "title": "Coordinate System issues",
  "url": "/competitions/cmi-detect-behavior-with-sensor-data/discussion/585695",
  "author_name": "",
  "post_date": "2025-06-22T13:03:27.948523400Z",
  "votes": 1,
  "comment_count": 1,
  "views": 0,
  "content": "<p>Has anyone analyzed the world coordinate system corresponds to the quaternion? Based on my preliminary observations, it seems like that  the world coordinate system is perpendicular to the ground, but But I'm not sure whether the world coordinate system remains consistent across different subjects and sequences, especially for the X/Y axes. What are your thoughts on this?</p>",
  "messages": [
    {
      "id": "3230054",
      "postDate": "06/22/2025 13:03:27",
      "content": "<p>Has anyone analyzed the world coordinate system corresponds to the quaternion? Based on my preliminary observations, it seems like that  the world coordinate system is perpendicular to the ground, but But I'm not sure whether the world coordinate system remains consistent across different subjects and sequences, especially for the X/Y axes. What are your thoughts on this?</p>",
      "rawMarkdown": "Has anyone analyzed the world coordinate system corresponds to the quaternion? Based on my preliminary observations, it seems like that  the world coordinate system is perpendicular to the ground, but But I'm not sure whether the world coordinate system remains consistent across different subjects and sequences, especially for the X/Y axes. What are your thoughts on this?",
      "votes": null
    },
    {
      "id": "3230241",
      "postDate": "06/22/2025 16:07:13",
      "content": "<p>If you look at the data page and examine the IMU sensor you will see it has a magnetometer. We are not given this data so I suspect that all data has been rotated so everyone has the same heading. This would make x,y more consistent between different trials. </p>",
      "rawMarkdown": "If you look at the data page and examine the IMU sensor you will see it has a magnetometer. We are not given this data so I suspect that all data has been rotated so everyone has the same heading. This would make x,y more consistent between different trials.",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 3230241,
      "author_name": "devinanzelmo",
      "author_url": "",
      "post_date": "06/22/2025 16:07:13",
      "content": "<p>If you look at the data page and examine the IMU sensor you will see it has a magnetometer. We are not given this data so I suspect that all data has been rotated so everyone has the same heading. This would make x,y more consistent between different trials. </p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "3230054": "Has anyone analyzed the world coordinate system corresponds to the quaternion? Based on my preliminary observations, it seems like that  the world coordinate system is perpendicular to the ground, but But I'm not sure whether the world coordinate system remains consistent across different subjects and sequences, especially for the X/Y axes. What are your thoughts on this?",
    "3230241": "If you look at the data page and examine the IMU sensor you will see it has a magnetometer. We are not given this data so I suspect that all data has been rotated so everyone has the same heading. This would make x,y more consistent between different trials."
  },
  "source": "meta"
}