$center

该 $center 运算符使用要用于查询的 $geoWithin 旧坐标对指定圆圈。 它为平面、欧克里丹平面上的地理空间查询定义圆圈。

语法

{
  $geoWithin: {
    $center: [ [ <x>, <y> ], <radius> ]
  }
}

参数

例子

让我们了解 stores 数据集中的示例 json 的用法。

{
  "_id": "a715ab0f-4c6e-4e9d-a812-f2fab11ce0b6",
  "name": "Lakeshore Retail | Holiday Supply Hub - Marvinfort",
  "location": { "lat": -74.0427, "lon": 160.8154 },
  "staff": { "employeeCount": { "fullTime": 9, "partTime": 18 } },
  "sales": {
    "salesByCategory": [ { "categoryName": "Stockings", "totalSales": 25731 } ],
    "revenue": 25731
  },
  "promotionEvents": [
    {
      "eventName": "Mega Savings Extravaganza",
      "promotionalDates": {
        "startDate": { "Year": 2023, "Month": 6, "Day": 29 },
        "endDate": { "Year": 2023, "Month": 7, "Day": 7 }
      },
      "discounts": [
        { "categoryName": "Stockings", "discountPercentage": 16 },
        { "categoryName": "Tree Ornaments", "discountPercentage": 8 }
      ]
    },
    {
      "eventName": "Incredible Discount Days",
      "promotionalDates": {
        "startDate": { "Year": 2023, "Month": 9, "Day": 27 },
        "endDate": { "Year": 2023, "Month": 10, "Day": 4 }
      },
      "discounts": [
        { "categoryName": "Stockings", "discountPercentage": 11 },
        { "categoryName": "Holiday Cards", "discountPercentage": 9 }
      ]
    },
    {
      "eventName": "Massive Deal Mania",
      "promotionalDates": {
        "startDate": { "Year": 2023, "Month": 12, "Day": 26 },
        "endDate": { "Year": 2024, "Month": 1, "Day": 2 }
      },
      "discounts": [
        { "categoryName": "Gift Bags", "discountPercentage": 21 },
        { "categoryName": "Bows", "discountPercentage": 19 }
      ]
    },
    {
      "eventName": "Super Saver Soiree",
      "promotionalDates": {
        "startDate": { "Year": 2024, "Month": 3, "Day": 25 },
        "endDate": { "Year": 2024, "Month": 4, "Day": 1 }
      },
      "discounts": [
        { "categoryName": "Tree Ornaments", "discountPercentage": 15 },
        { "categoryName": "Stockings", "discountPercentage": 14 }
      ]
    },
    {
      "eventName": "Fantastic Savings Fiesta",
      "promotionalDates": {
        "startDate": { "Year": 2024, "Month": 6, "Day": 23 },
        "endDate": { "Year": 2024, "Month": 6, "Day": 30 }
      },
      "discounts": [
        { "categoryName": "Stockings", "discountPercentage": 24 },
        { "categoryName": "Gift Wrap", "discountPercentage": 16 }
      ]
    },
    {
      "eventName": "Price Plunge Party",
      "promotionalDates": {
        "startDate": { "Year": 2024, "Month": 9, "Day": 21 },
        "endDate": { "Year": 2024, "Month": 9, "Day": 28 }
      },
      "discounts": [
        { "categoryName": "Holiday Tableware", "discountPercentage": 13 },
        { "categoryName": "Holiday Cards", "discountPercentage": 11 }
      ]
    }
  ],
  "company": "Lakeshore Retail",
  "city": "Marvinfort",
  "storeOpeningDate": { "$date": "2024-10-01T18:24:02.586Z" },
  "lastUpdated": { "$timestamp": { "t": 1730485442, "i": 1 } },
  "storeFeatures": 38
}

示例 1 - 查找圆形区域内的存储

让我们使用数据集 stores 在“第一次向上顾问麦克风集市”的 50 度半径内查找所有商店。 此查询检索第一个 Up 顾问麦克风集市位置的 50 度半径内的存储。

db.stores.find(
  {
    location: {
      $geoWithin: {
        $center: [[-112.7858, -29.1866], 50]
      }
    }
  },
  {
    name: 1,
    city: 1,
    location: 1,
    _id: 0
  }
).limit(2)

查询返回 50 度半径内的存储，这对于分析市场覆盖范围或规划交付路线很有用。

[
  {
    "name": "Contoso, Ltd. | Baby Products Corner - Port Jerrold",
    "location": { "lat": -72.7709, "lon": -24.3031 },
    "city": "Port Jerrold"
  },
  {
    "name": "VanArsdel, Ltd. | Smart Home Closet - Trystanport",
    "location": { "lat": -64.5509, "lon": -28.7144 },
    "city": "Trystanport"
  }
]

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