> For the complete documentation index, see [llms.txt](https://tritueviet.gitbook.io/server/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tritueviet.gitbook.io/server/master.md).

# Mongo

## Find Nearest Locations With MongoDB — How To? <a href="#id-89e1" id="id-89e1"></a>

![](/files/-MJwIcU323sEax-S4_Y7)

There are many ways to implement finding nearest locations by given **latitude and longitude** .

Some of the **implementations** can be achieved through a **backend logic**,

and the other ways can be done by **utilizing** some features(**Spatial Indexes**) provided by **DBMSs**’(Mysql, SQL, MongoDB,….etc).

**In this post I will explain by example how we can do it with MongoDB.**

> **What are Latitude and Longitude?** , You can find more from here <https://www.latlong.net/>

## How To ? <a href="#id-802d" id="id-802d"></a>

Let’s create a collection in MongoDb and we call it `locations` .

> To Achieve the query of **finding nearest locations by given latitude and longitude**, we do the following **Steps**:
>
> **First Step** : Each stored document must follow a structure called **GeoJSON .**
>
> **Second Step** : We have to create **2dsphere** Index in that collection .
>
> **Third Step** : We run the **Find query**! .

## First Step: GeoJSON <a href="#id-6efd" id="id-6efd"></a>

The `locations` collection will store a list of documents, each one of them represents a location(or an address) on the map.&#x20;

Each document will **follow** this example/structure:

```
{
  "country": "UAE",
  "city": "Dubai",
  "address": "Dubai Mall",
  "loc": {
    "type": "Point",
    "coordinates": [
      25.1973,//latitude
      55.2793 //longitude
    ]
  }
}
```

This Structure is following **GeoJSON Structure!**

— What’s **GeoJSON Structure?**

It is a JSON document that must have an object inside it , as follows :

```
<field>: { type: <GeoJSON type> , coordinates: <coordinates> }
```

Projection on the previous (Dubai Mall) document :

```
"loc" : {"type" : "Point" , "coordinates" : [25.1973,55.2793]}
```

> Read more about : **GeoJSON** Object <https://docs.mongodb.com/manual/reference/geojson/>

Ok, Great!, till now we’ve created `locations` collection that has a list of documents that follow **GeoJSON** structure, so let’s suppose we have those documents inside `locations`:

## **Second Step : Index Creation** <a href="#id-4b0e" id="id-4b0e"></a>

We need to run **createIndex** Command to tell MongoDb that this collection is following the **GeoJSON** structure, so we can achieve the query of finding nearest locations successfully.

Command syntax:

```
db.collection.createIndex( { <location field> : "2dsphere" } )
```

Projection:

```
db.locations.createIndex( { "loc" : "2dsphere" } )
```

## **Third Step :** Find Query <a href="#dad9" id="dad9"></a>

As Per MongoDb documentation, here is the syntax of finding nearest locations by given latitude/longitude:

```
db.collection.find(
{
   <location field>: {
     $near: {
       $geometry: {
          type: "Point" ,
          coordinates: [ <longitude> , <latitude> ]
       },
     }
   }
})
```

If I want to get the nearest locations to my current location, I should provide my current latitude/longitude, so let’s suppose

My Current Latitude: **25.087626** / Longitude: **55.151134 . (Dubai Marina)**

So when I query the collection, we do:

```
db.locations.find(
{
   "loc": {
     $near: {
       $geometry: {
          type: "Point" ,
          coordinates: [ 25.087626 , 55.151134 ]
       },
     }
   }
})
```

**Query Result: (ordered by nearest, according to my Latitude :25.087626/Longitude : 55.151134)**

This is it!, Hope you find this information useful!

```
db.collectionname.find({
    "location": {
        $near: {
            $geometry:
                { type: "Point", coordinates: [50.0, -0.1330] }, $maxDistance: 500
        }
    }
})

db.address.find ({
  location: {
     $near: {
       $geometry: {
          type: "Point" ,
          coordinates: [ -72.7738706,41.6332836 ]
       },
       $maxDistance: 4,
       $minDistance: 0
     }
   }
})
```