How to calculate distance between two geolocation points?

Working with Data
,
1

If we know longitude and latitude of the geolocation points, how we can calculate the distance between them?

For example, image this input document:

[
  {
    "location_1": {
      "type": "Point",
      "coordinates": [
        10,
        20
      ]
    },
    "location_2": {
      "type": "Point",
      "coordinates": [
        10,
        30
      ]
    }
  }
]

How can we calculate the distance between location_1 and location_2?

2

Hi @NeNaD,

Would the distance calculated with distance = √ ((x2-x1)² + (y2-y1)²) work for you?

> db.coll.findOne()
{
  _id: ObjectId("62c43a4128c8b27fda436536"),
  location_1: { type: 'Point', coordinates: [ 10, 20 ] },
  location_2: { type: 'Point', coordinates: [ 10, 30 ] }
}

Aggregation:

[
  {
    '$addFields': {
      'distance': {
        '$sqrt': {
          '$add': [
            {
              '$pow': [
                {
                  '$subtract': [
                    {
                      '$arrayElemAt': [
                        '$location_2.coordinates', 0
                      ]
                    }, {
                      '$arrayElemAt': [
                        '$location_1.coordinates', 0
                      ]
                    }
                  ]
                }, 2
              ]
            }, {
              '$pow': [
                {
                  '$subtract': [
                    {
                      '$arrayElemAt': [
                        '$location_2.coordinates', 1
                      ]
                    }, {
                      '$arrayElemAt': [
                        '$location_1.coordinates', 1
                      ]
                    }
                  ]
                }, 2
              ]
            }
          ]
        }
      }
    }
  }
]

Result:

[
  {
    _id: ObjectId("62c43a4128c8b27fda436536"),
    location_1: { type: 'Point', coordinates: [ 10, 20 ] },
    location_2: { type: 'Point', coordinates: [ 10, 30 ] },
    distance: 10
  }
]

Cheers,
Maxime.

1 Like
3

Hi @MaBeuLux88,

Thanks for the response! :smiley:

Actually, it should be calculated like in this SO answer here.

I just though that maybe I can use some built-in operator for that. Can you tell me where I can submit a proposal for new operators?

4

I was actually afraid you would say something like that! :sweat_smile:

Well this calculation can also be done as their is also $cos, $sin, etc in the trigonometry operators. But my formula is probably good enough if you have all your points within the same city for example.

If this operator exists, I never heard of it.

Feedback & improvements are in this direction though and I like the idea! I would have also liked to find the “$distance” one that I had to “implement” in here…

https://feedback.mongodb.com/

Cheers,
Maxime.

5

Yeah, it would be great to have both of these built-in with some operator. Let me submit both suggestions! :smiley:

6

Submitted. :smiley:

Here is the suggestion, so everyone that would love to see these operators built-in can go and upvote the suggestion.

2 Likes
7

Looks like it’s already in the backlog actually:

https://jira.mongodb.org/browse/SERVER-2990

I added my vote on it!

1 Like
8

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