// 找捷運台北車站附近距離2公里內的捷運站
db.lbs_test.aggregate(
    {
        $geoNear : {
            near : [25.046084,121.517542],
            distanceField : "dist",
            maxDistance : 2 / 111.12
        }
    }
);

// 查詢結果
{
        "result" : [
                {
                        "_id" : ObjectId("5238179cdfba7ac818bb5fcd"),
                        "name" : "捷運臺大醫院站",
                        "loc" : {
                                "lat" : 25.041535,
                                "long" : 121.516029
                        },
                        "time" : 11,
                        "dist" : 0.004794013975784349
                },
                {
                        "_id" : ObjectId("5238179cdfba7ac818bb5fd2"),
                        "name" : "捷運中山站",
                        "loc" : {
                                "lat" : 25.052596,
                                "long" : 121.520327
                        },
                        "time" : 16,
                        "dist" : 0.0070825397280881355
                },
                {
                        "_id" : ObjectId("5238179cdfba7ac818bb5fd3"),
                        "name" : "捷運雙連站",
                        "loc" : {
                                "lat" : 25.057961,
                                "long" : 121.520842
                        },
                        "time" : 17,
                        "dist" : 0.012326926989316265
                },
                {
                        "_id" : ObjectId("5238179cdfba7ac818bb5fce"),
                        "name" : "捷運中正紀念堂站",
                        "loc" : {
                                "lat" : 25.032922,
                                "long" : 121.518481
                        },
                        "time" : 12,
                        "dist" : 0.01319545243635133
                },
                {
                        "_id" : ObjectId("523817b1dfba7ac818bb5fdd"),
                        "name" : "捷運東門站",
                        "loc" : {
                                "lat" : 25.033972,
                                "long" : 121.528695
                        },
                        "time" : 27,
                        "dist" : 0.01646480953427314
                },
                {
                        "_id" : ObjectId("523817b1dfba7ac818bb5fdc"),
                        "name" : "捷運松江南京站",
                        "loc" : {
                                "lat" : 25.051974,
                                "long" : 121.53303
                        },
                        "time" : 26,
                        "dist" : 0.016570161254487518
                },
                {
                        "_id" : ObjectId("5238179ddfba7ac818bb5fd4"),
                        "name" : "捷運民權西路站",
                        "loc" : {
                                "lat" : 25.063093,
                                "long" : 121.519425
                        },
                        "time" : 18,
                        "dist" : 0.017112912376328723
                }
        ],
        "ok" : 1
}