MongoDB/Mongoose - Aggregation with geoNear & subdocuments

First a disclaimer: I am not a Node/Mongoose expert so I am hoping you can translate the general formats to Node/Mongoose.

For the error:

 errmsg: "exception: 'near' field must be point"

For a '2d' index this cannot be a GeoJson point and instead needs to be a "legacy coordinate pair". e.g.,

{  "$geoNear": {    "near": geo.ll,    "maxDistance": 40000,    "distanceField": "dist.calculated"  }}

If you want to use GeoJSON you will need to use a '2dsphere' index.

With that change the $geoNear query will work with the array of points in the query. An example in the shell:

> db.test.createIndex({ "locations": "2d" })> db.test.insert({ "locations": [ [1, 2], [10, 20] ] });> db.test.insert({ "locations": [ [100, 100], [180, 180] ] });> db.test.aggregate([{  "$geoNear": {    "near": [10, 10],    "maxDistance": 40000,    "distanceField": "dist.calculated",    num: 1  }}]);{  "result": [{    "_id": ObjectId("552aaf7478dd9c25a3472a2a"),    "locations": [      [        1,        2      ],      [        10,        20      ]    ],    "dist": {      "calculated": 10    }  }],  "ok": 1}

Note that you only get a single distance per document (the closest point) which is semantically not the same as doing the unwind and then determining the distance to every point. I cannot be sure if that is important for your use case.