Filter Results Inside a Rectangle

In this tutorial, we’ll see how we can filter results inside a rectangle area. This location can either be set manually or taken from the current user position.

Dataset

The dataset contains 3000+ of the biggest airports in the world.

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[
 {
    "objectID": "3797",
    "name": "John F Kennedy Intl",
    "city": "New York",
    "country": "United States",
    "iata_code": "JFK",
    "_geoloc": {
      "lat": 40.639751,
      "lng": -73.778925
    },
    "links_count": 911
  }
]

To tell Algolia where each record is located, we need to have the latitude and longitude stored in the _geoloc attribute.

You can download the dataset here. Have look at how to import it in Algolia here

Initialize the client

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// composer autoload
require __DIR__ . '/vendor/autoload.php';

// if you are not using composer
// require_once 'path/to/algoliasearch.php';

$client = \Algolia\AlgoliaSearch\SearchClient::create(
  'YourApplicationID',
  'YourAdminAPIKey'
);

$index = $client->initIndex('your_index_name');

Configure Index Settings

Even if we want to sort by distance to a location we need the textual relevance to be good in case refine the search with a query.

First, let’s configure the index.

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$index->setSettings({
  'searchableAttributes' => [
    'name',
    'city',
    'country',
    'iata_code'
  ],
  'customRanking': [
    'desc(links_count)'
  ]
});

Searchable attributes

We’re going to search in our 4 textual attributes: name, city, country and iata_code.

Custom Ranking

We’ll use the number of other connected airports to any airport as a ranking metric. The more connection the better.

Filtering inside a rectangle area

Let’s filter inside the United State of America. The USA can be considered as a rectangle:

To filter inside this rectangle we need the upper-left and bottom-right latitude and longitude:

  • 49.067996905313834, 65.73828125
  • 25.905859247243498, 128.8046875

We are going to use the insideBoundingBox parameter:

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$boundingBox = [
  49.067996905313834, // p1Lat
  65.73828125, // p1Lng
  25.905859247243498, // p2Lat
  128.8046875 // p2Lng
];

$results = $index->search('', [
  'insideBoundingBox' => [$boundingBox]
]);

We are using the empty query ('') to tell that we want all airports.

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