{
  "id": 189458,
  "title": "_meta.json",
  "url": "/competitions/lyft-motion-prediction-autonomous-vehicles/discussion/189458",
  "author_name": "",
  "post_date": "2020-10-07T16:58:16.655365400Z",
  "votes": null,
  "comment_count": 2,
  "views": 0,
  "content": "<p>Kindly someone explains about following numbers, please. Why we need them? </p>\n<pre><code>\"world_to_ecef\": [\n    [\n        0.846617444,\n        0.323463078,\n        -0.422623402,\n        -2698767.44\n    ],\n    [\n        -0.532201938,\n        0.514559352,\n        -0.672301845,\n        -4293151.58\n    ],\n    [\n        -3.05311332e-16,\n        0.794103464,\n        0.6077826,\n        3855164.76\n    ],\n    [\n        0.0,\n        0.0,\n        0.0,\n        1.0\n    ]\n],\n\"ecef_to_aerial\": [\n    [\n        -7.17416495e-01,\n        -1.14606296e+00,\n        -1.62854453e+00,\n        -5.72869824e+05\n    ],\n    [\n        1.80065798e+00,\n        -1.08914046e+00,\n        -2.87877303e-02,\n        3.00171963e+05\n    ],\n    [\n        0.00000000e+00,\n        0.00000000e+00,\n        0.00000000e+00,\n        0.00000000e+00\n    ],\n    [\n        0.00000000e+00,\n        0.00000000e+00,\n        0.00000000e+00,\n        1.00000000e+00\n    ]\n]\n</code></pre>\n<p>}</p>",
  "messages": [
    {
      "id": "1041272",
      "postDate": "10/07/2020 16:58:16",
      "content": "<p>Kindly someone explains about following numbers, please. Why we need them? </p>\n<pre><code>\"world_to_ecef\": [\n    [\n        0.846617444,\n        0.323463078,\n        -0.422623402,\n        -2698767.44\n    ],\n    [\n        -0.532201938,\n        0.514559352,\n        -0.672301845,\n        -4293151.58\n    ],\n    [\n        -3.05311332e-16,\n        0.794103464,\n        0.6077826,\n        3855164.76\n    ],\n    [\n        0.0,\n        0.0,\n        0.0,\n        1.0\n    ]\n],\n\"ecef_to_aerial\": [\n    [\n        -7.17416495e-01,\n        -1.14606296e+00,\n        -1.62854453e+00,\n        -5.72869824e+05\n    ],\n    [\n        1.80065798e+00,\n        -1.08914046e+00,\n        -2.87877303e-02,\n        3.00171963e+05\n    ],\n    [\n        0.00000000e+00,\n        0.00000000e+00,\n        0.00000000e+00,\n        0.00000000e+00\n    ],\n    [\n        0.00000000e+00,\n        0.00000000e+00,\n        0.00000000e+00,\n        1.00000000e+00\n    ]\n]\n</code></pre>\n<p>}</p>",
      "rawMarkdown": "Kindly someone explains about following numbers, please. Why we need them? \n\n    \"world_to_ecef\": [\n        [\n            0.846617444,\n            0.323463078,\n            -0.422623402,\n            -2698767.44\n        ],\n        [\n            -0.532201938,\n            0.514559352,\n            -0.672301845,\n            -4293151.58\n        ],\n        [\n            -3.05311332e-16,\n            0.794103464,\n            0.6077826,\n            3855164.76\n        ],\n        [\n            0.0,\n            0.0,\n            0.0,\n            1.0\n        ]\n    ],\n    \"ecef_to_aerial\": [\n        [\n            -7.17416495e-01,\n            -1.14606296e+00,\n            -1.62854453e+00,\n            -5.72869824e+05\n        ],\n        [\n            1.80065798e+00,\n            -1.08914046e+00,\n            -2.87877303e-02,\n            3.00171963e+05\n        ],\n        [\n            0.00000000e+00,\n            0.00000000e+00,\n            0.00000000e+00,\n            0.00000000e+00\n        ],\n        [\n            0.00000000e+00,\n            0.00000000e+00,\n            0.00000000e+00,\n            1.00000000e+00\n        ]\n    ]\n}",
      "votes": null
    },
    {
      "id": "1041884",
      "postDate": "10/08/2020 00:40:26",
      "content": "<p>Some parts of the dataset are from different sources, and happen to use different coordinate systems. So we need to be able to transform some coordinates into different systems, to have them all available in a same one. And that's where the transform matrices and matrix multiplication come in.</p>",
      "rawMarkdown": "Some parts of the dataset are from different sources, and happen to use different coordinate systems. So we need to be able to transform some coordinates into different systems, to have them all available in a same one. And that's where the transform matrices and matrix multiplication come in.",
      "votes": null
    },
    {
      "id": "1042503",
      "postDate": "10/08/2020 09:06:44",
      "content": "<p>The <code>world_to_ecef</code> matrix transforms dataset coordinates into Earth-Centred Earth-Fixed coordinates. This is used for satellite rasterisation.<br>\nThe <code>ecef_to_aerial</code> is the second piece you need to go from the previous (ECEF) system to the satellite image (pixels) stored in the dataset.</p>\n<p>More detailed information <a href=\"https://github.com/lyft/l5kit/blob/master/coords_systems.md\" target=\"_blank\">here</a>  :) </p>",
      "rawMarkdown": "The `world_to_ecef` matrix transforms dataset coordinates into Earth-Centred Earth-Fixed coordinates. This is used for satellite rasterisation.\nThe `ecef_to_aerial` is the second piece you need to go from the previous (ECEF) system to the satellite image (pixels) stored in the dataset.\n\nMore detailed information [here](https://github.com/lyft/l5kit/blob/master/coords_systems.md)  :)",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 1041884,
      "author_name": "n3n77i",
      "author_url": "",
      "post_date": "10/08/2020 00:40:26",
      "content": "<p>Some parts of the dataset are from different sources, and happen to use different coordinate systems. So we need to be able to transform some coordinates into different systems, to have them all available in a same one. And that's where the transform matrices and matrix multiplication come in.</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 1042503,
      "author_name": "lucabergamini",
      "author_url": "",
      "post_date": "10/08/2020 09:06:44",
      "content": "<p>The <code>world_to_ecef</code> matrix transforms dataset coordinates into Earth-Centred Earth-Fixed coordinates. This is used for satellite rasterisation.<br>\nThe <code>ecef_to_aerial</code> is the second piece you need to go from the previous (ECEF) system to the satellite image (pixels) stored in the dataset.</p>\n<p>More detailed information <a href=\"https://github.com/lyft/l5kit/blob/master/coords_systems.md\" target=\"_blank\">here</a>  :) </p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "1041272": "Kindly someone explains about following numbers, please. Why we need them? \n\n    \"world_to_ecef\": [\n        [\n            0.846617444,\n            0.323463078,\n            -0.422623402,\n            -2698767.44\n        ],\n        [\n            -0.532201938,\n            0.514559352,\n            -0.672301845,\n            -4293151.58\n        ],\n        [\n            -3.05311332e-16,\n            0.794103464,\n            0.6077826,\n            3855164.76\n        ],\n        [\n            0.0,\n            0.0,\n            0.0,\n            1.0\n        ]\n    ],\n    \"ecef_to_aerial\": [\n        [\n            -7.17416495e-01,\n            -1.14606296e+00,\n            -1.62854453e+00,\n            -5.72869824e+05\n        ],\n        [\n            1.80065798e+00,\n            -1.08914046e+00,\n            -2.87877303e-02,\n            3.00171963e+05\n        ],\n        [\n            0.00000000e+00,\n            0.00000000e+00,\n            0.00000000e+00,\n            0.00000000e+00\n        ],\n        [\n            0.00000000e+00,\n            0.00000000e+00,\n            0.00000000e+00,\n            1.00000000e+00\n        ]\n    ]\n}",
    "1041884": "Some parts of the dataset are from different sources, and happen to use different coordinate systems. So we need to be able to transform some coordinates into different systems, to have them all available in a same one. And that's where the transform matrices and matrix multiplication come in.",
    "1042503": "The `world_to_ecef` matrix transforms dataset coordinates into Earth-Centred Earth-Fixed coordinates. This is used for satellite rasterisation.\nThe `ecef_to_aerial` is the second piece you need to go from the previous (ECEF) system to the satellite image (pixels) stored in the dataset.\n\nMore detailed information [here](https://github.com/lyft/l5kit/blob/master/coords_systems.md)  :)"
  },
  "source": "meta"
}