CakePHP query closest latitude longitude from database

Question

In a CakePHP (v3) application, how can I retrieve the closest results based on passed lat lng values?

I'd like to have them back as native CakePHP entities, so something like this:

public function closest($lat, $lng) {

    $sightings = //records within given lat lng 

    $this->set(compact('sightings'));
    $this->set('_serialize', ['sightings']);
}

I know this SQL works:

SELECT *,
       ( 3959 * acos( cos( radians(50.7) ) * cos( radians( latitude ) ) * cos( radians( longitude ) - radians(-1.8) ) + sin( radians(50.7) ) * sin( radians( latitude ) ) ) ) AS distance
  FROM sightings
HAVING distance < 10
 ORDER BY distance
 LIMIT 0 , 20

Struggling to combine the two.

UPDATE

I've added

class Sighting extends Entity {
    public $_virtual = ['distance'];
    //rest of class...
}

So now the distance is showing up in my json output (with the value of null as would be expected right now, but I feel it's a step at lease).

I've taken a look here: http://www.mrthun.com/2014/11/26/search-distance-cakephp/ which seems to be what I'm trying to achieve so assumed something like this:

$latitude = 51.145;
$longitude = -1.45;
$distance = 100;

$this->Sightings->virtualFields
    = array('Sightings.distance'
     => '(3959 * acos (cos ( radians('.$latitude.') )
    * cos( radians( Sightings.latitude ) )
    * cos( radians( Sightings.longitude )
    - radians('.$longitude.') )
    + sin ( radians('.$latitude.') )
    * sin( radians( Sightings.latitude ) )))');

$sightings = $this->Sightings->find('all', [
    'conditions' => ['Sightings.distance <' => $distance]
]);

$this->set(compact('sightings'));
$this->set('_serialize', ['sightings']);

Results in: Column not found: 1054 Unknown column 'Sightings.distance' in 'where clause'

Not sure if it's possible CakePHP v2 as opposed to v3?

Answer 1

there are no more virtualFields in cake 3 but you still can create an alias for your calculated field

As suggested by @ndm you'd better bind $latitude and $longitude to prevent SQL injections

$distanceField = '(3959 * acos (cos ( radians(:latitude) )
    * cos( radians( Sightings.latitude ) )
    * cos( radians( Sightings.longitude )
    - radians(:longitude) )
    + sin ( radians(:latitude) )
    * sin( radians( Sightings.latitude ) )))';

using where

$sightings = $this->Sightings->find()
    ->select([
        'distance' => $distanceField
    ])
    ->where(["$distanceField < " => $distance])
    ->bind(':latitude', $latitude, 'float')
    ->bind(':longitude', $longitude, 'float')
    ->contain(['Photos', 'Tags']);

using having

$sightings = $this->Sightings->find()
    ->select([
        'distance' => $distanceField
    ])
    ->having(['distance < ' => $distance])
    ->bind(':latitude', $latitude, 'float')
    ->bind(':longitude', $longitude, 'float')
    ->contain(['Photos', 'Tags']);

Answer 2

You need to use ConnectionManager here.

For example:

use Cake\Datasource\ConnectionManager;  // Mention this first, preferably on top of the page.

$connection = ConnectionManager::get('default');

$results = $connection
  ->execute('SELECT * FROM articles WHERE id = :id', ['id' => 1])
  ->fetchAll('assoc');

You could try and set up your query in this fashion. It will definitely work.

Use this as a reference:

SELECT Statements with CakePHP 3

Answer 3

There are several approaches to achieve your result.

1. Raw Query

Instead of struggling with the ORM, you could perform a raw query?

$conn = ConnectionManager::get('my_connection');

And then you can run a custom query like:

$results = $conn->execute('MY RAW SQL HERE');

2. Raw Query w/Eager loading

If you want to run a query and eager load the relations, you will need to use the contains method like:

$query = $articles->find('all', ['contain' => ['Authors', 'Comments']]);

3. Using Virtual Fields

If you want to use virtual fields like in your example above, you need to add it in your entity model class like:

protected function _getDistance()
{
    //access model members using $this->_properties e.g.
    //return $this->_properties['latitude'] . '  ' .
    //    $this->_properties['longitude'];
}

This should ensure your distance is no longer null in your json.

And you could use with the distance method from CakephpGeo library to construct a query

public function distance(array $pointX, array $pointY) {
    $res = $this->calculateDistance($pointX, $pointY);
    return ceil($res);
}

public static function calculateDistance($pointX, $pointY) {
    $res = 69.09 * rad2deg(acos(sin(deg2rad($pointX['lat'])) * sin(deg2rad($pointY['lat']))
        + cos(deg2rad($pointX['lat'])) * cos(deg2rad($pointY['lat'])) * cos(deg2rad($pointX['lng']
        - $pointY['lng']))));
    return $res;
}

4. Raw PHP

Lastly, and not recommended, you could retrieve all the info you need and use PHP to narrow down your results. Painful, slow and not recommended.

Answer 4

finally i got the solution for this. below is the working example

$distance = 25;
$start_latitude = 12.920479;
$start_longitude = 77.670547;

$contents = $this->Sightings->find()->select(['latitude', 'longitude', 'distance' => 'SQRT(
    POW(69.1 * (latitude - '.$start_latitude.'), 2) +
    POW(69.1 * ('.$start_longitude.' - longitude) * COS(latitude / 57.3), 2))'])->having(["distance < " => $distance]);

output

   {"lat": xx.920479,
    "lng": xx.670547,
    "distance": "0"
   }

Answer 5

People might want to look at the CakePHP GeoDistance Plugin:

CakePHP-GeoDistance is a CakePHP 3 behavior for querying geocoded data based on cartographic distance using the spherical cosine law. It is great for 'find my nearest X' or 'find Y near me' type queries.

https://github.com/chris48s/cakephp-geodistance

Did the job.