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# \$1geometry
<a name="geometry"></a>

Amazon DocumentDB 中的`$geometry`運算子用於指定 GeoJSON 幾何物件做為地理空間查詢的一部分。此運算子會與其他地理空間查詢運算子搭配使用，例如 `$geoWithin`和 `$geoIntersects`，以對您的資料執行空間查詢。

在 Amazon DocumentDB 中，`$geometry`運算子支援下列 GeoJSON 幾何類型：
+ 點 (Point)
+ LineString
+ 多邊形
+ MultiPoint
+ MultiLineString
+ MultiPolygon
+ GeometryCollection

**參數**
+ `type`：GeoJSON 幾何物件的類型，例如 、 `Point``Polygon`等。
+ `coordinates`：代表幾何的座標陣列。座標陣列的結構取決於幾何類型。

## 範例 (MongoDB Shell)
<a name="geometry-examples"></a>

下列範例示範如何使用 `$geometry`運算子在 Amazon DocumentDB 中執行`$geoIntersects`查詢。

**建立範例文件**

```
db.locations.insertMany([
  { 
    "_id": 1,
    "name": "Location 1",
    "location": { 
      "type": "Point",
      "coordinates": [-73.983253, 40.753941]
    }
  },
  { 
    "_id": 2,
    "name": "Location 2", 
    "location": {
      "type": "Polygon",
      "coordinates": [[
        [-73.998427, 40.730309],
        [-73.954348, 40.730309],
        [-73.954348, 40.780816],
        [-73.998427, 40.780816],
        [-73.998427, 40.730309]
      ]]
    }
  }
]);
```

**查詢範例**

```
db.locations.find({
  "location": {
    "$geoIntersects": {
      "$geometry": {
        "type": "Polygon",
        "coordinates": [[
          [-73.998, 40.730],
          [-73.954, 40.730],
          [-73.954, 40.781],
          [-73.998, 40.781],
          [-73.998, 40.730]
        ]]
      }
    }
  }
})
```

**輸出**

```
[
  {
    "_id": 2,
    "name": "Location 2",
    "location": {
      "type": "Polygon",
      "coordinates": [
        [
          [-73.998427, 40.730309],
          [-73.954348, 40.730309],
          [-73.954348, 40.780816],
          [-73.998427, 40.780816],
          [-73.998427, 40.730309]
        ]
      ]
    }
  }
]
```

## 程式碼範例
<a name="geometry-code"></a>

若要檢視使用 `$geometry`命令的程式碼範例，請選擇您要使用的語言標籤：

------
#### [ Node.js ]

```
const { MongoClient } = require('mongodb');

async function example() {
  const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  const db = client.db('test');
  const collection = db.collection('locations');

  const query = {
    "location": {
      "$geoIntersects": {
        "$geometry": {
          "type": "Polygon",
          "coordinates": [[
            [-73.998, 40.730],
            [-73.954, 40.730],
            [-73.954, 40.781],
            [-73.998, 40.781],
            [-73.998, 40.730]
          ]]
        }
      }
    }
  };

  const result = await collection.find(query).toArray();
  console.log(result);

  await client.close();
}

example();
```

------
#### [ Python ]

```
from pymongo import MongoClient

def example():
    client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
    db = client['test']
    collection = db['locations']

    query = {
        "location": {
            "$geoIntersects": {
                "$geometry": {
                    "type": "Polygon",
                    "coordinates": [[
                        [-73.998, 40.730],
                        [-73.954, 40.730],
                        [-73.954, 40.781],
                        [-73.998, 40.781],
                        [-73.998, 40.730]
                    ]]
                }
            }
        }
    }

    result = list(collection.find(query))
    print(result)

    client.close()

example()
```

------