Geonear Node.js Mongdb无法正常工作

Question

我使用geonear的nodejs应用程序出现错误，如果有人可以帮助我，我将不理解输出错误：

{
"error": {
    "name": "MongoError",
    "message": "geoNear command failed: { ok: 0.0, errmsg: \"error processing query: ns=Lab.userprofiles limit=100Tree: GEONEAR  field=loc maxdist=2000 isNearSphere=1\nSort: {}\nProj: { $pt: { $meta: \"geoNearPoint...\", code: 2, codeName: \"BadValue\" }",
    "ok": 0,
    "errmsg": "geoNear command failed: { ok: 0.0, errmsg: \"error processing query: ns=Lab.userprofiles limit=100Tree: GEONEAR  field=loc maxdist=2000 isNearSphere=1\nSort: {}\nProj: { $pt: { $meta: \"geoNearPoint...\", code: 2, codeName: \"BadValue\" }",
    "code": 16604,
    "codeName": "Location16604"
}
}

下面是集合的架构：

const mongoose = require("mongoose");
var Schema = mongoose.Schema;

var UserSchema = new mongoose.Schema({
   userId:{ type: mongoose.Schema.Types.ObjectId, ref: "User"},
   picture : String,
   telephone: {
      type: String,
      unique: false
   },
   adresse:String,
   loc: {
      type: [Number], // [<longitude>, <latitude>]
      index: "2d" // create the geospatial index
   },
   sexe:String,
   metier:String,
   age:{ type : Array , "default" : [] },
   centreInterets:{ type : Array , "default" : [] },
   pays:String,
   ville:String,
   code_postal:Number,
   nom: String,
   prenom:String,
   status:String
});

var UserProfile = mongoose.model('UserProfile', UserSchema);
module.exports = UserProfile;

最后是查询：

exports.findVolontaires = (req, res, next) => {

  UserProfile.aggregate (
     [{
         $geoNear: {
           near : {
             type: "Point",
             coordinates: [-95.9953, 41.2000]
           },
           distanceField: "dist",
           maxDistance: 2000,
           spherical :true
         }
     }]
     , (err, results) => {
        if( err ) {
           return res.status(200).json({
              error : err
           })
        }

        return res.status(200).json({
           results : results
        })

     }
  )
}

感谢您的帮助，我已经尝试在mongodb文档中搜索解决方案，并在错误中使用Google搜索成功。