Filter results inside a polygon

In this tutorial, you’ll learn how to filter results around a polygonal location. This location can either be set manually or taken from the current user position. To run the code examples on this page, install the latest API client.

Dataset

The guide uses a dataset of the 3,000+ biggest airports in the world.

JSON

[
 {
    "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, the latitude and longitude must be stored in the _geoloc attribute.

Initialize the client

Configure index settings

Even if you just want to sort by distance to a location, your textual relevance should also be good so that users can refine the search with a query. To do that, you must configure the . The searchable attributes are: name, city, country, and iata_code.

var response = await client.SetSettingsAsync(
  "INDEX_NAME",
  new IndexSettings
  {
    SearchableAttributes = new List<string> { "name", "country", "city", "iata_code" },
    CustomRanking = new List<string> { "desc(links_count)" },
  }
);

final response = await client.setSettings(
  indexName: "INDEX_NAME",
  indexSettings: IndexSettings(
    searchableAttributes: [
      "name",
      "country",
      "city",
      "iata_code",
    ],
    customRanking: [
      "desc(links_count)",
    ],
  ),
);

response, err := client.SetSettings(client.NewApiSetSettingsRequest(
  "INDEX_NAME",
  search.NewEmptyIndexSettings().SetSearchableAttributes(
    []string{"name", "country", "city", "iata_code"}).SetCustomRanking(
    []string{"desc(links_count)"})))
if err != nil {
  // handle the eventual error
  panic(err)
}

UpdatedAtResponse response = client.setSettings(
  "INDEX_NAME",
  new IndexSettings()
    .setSearchableAttributes(Arrays.asList("name", "country", "city", "iata_code"))
    .setCustomRanking(Arrays.asList("desc(links_count)"))
);

const response = await client.setSettings({
  indexName: 'theIndexName',
  indexSettings: {
    searchableAttributes: ['name', 'country', 'city', 'iata_code'],
    customRanking: ['desc(links_count)'],
  },
});

var response =
  client.setSettings(
    indexName = "INDEX_NAME",
    indexSettings =
      IndexSettings(
        searchableAttributes = listOf("name", "country", "city", "iata_code"),
        customRanking = listOf("desc(links_count)"),
      ),
  )

$response = $client->setSettings(
    'INDEX_NAME',
    ['searchableAttributes' => [
        'name',

        'country',

        'city',

        'iata_code',
    ],
        'customRanking' => [
            'desc(links_count)',
        ],
    ],
);

response = client.set_settings(
    index_name="INDEX_NAME",
    index_settings={
        "searchableAttributes": [
            "name",
            "country",
            "city",
            "iata_code",
        ],
        "customRanking": [
            "desc(links_count)",
        ],
    },
)

response = client.set_settings(
  "INDEX_NAME",
  Algolia::Search::IndexSettings.new(
    searchable_attributes: ["name", "country", "city", "iata_code"],
    custom_ranking: ["desc(links_count)"]
  )
)

val response = Await.result(
  client.setSettings(
    indexName = "INDEX_NAME",
    indexSettings = IndexSettings(
      searchableAttributes = Some(Seq("name", "country", "city", "iata_code")),
      customRanking = Some(Seq("desc(links_count)"))
    )
  ),
  Duration(100, "sec")
)

let response = try await client.setSettings(
    indexName: "INDEX_NAME",
    indexSettings: IndexSettings(
        searchableAttributes: ["name", "country", "city", "iata_code"],
        customRanking: ["desc(links_count)"]
    )
)

Filtering inside a polygonal area

The USA can be considered as a polygon:

Screenshot of a map showing the United States with a polygonal filter drawn over it, highlighting a specific region.

To filter inside this rectangle, you need to pass the latitude and longitude of all the points to the insidePolygon parameter:

42.01,-124.31,
48.835509470063045,-124.40453125000005
45.01082951668149,-65.95726562500005
31.247243545293433,-81.06578125000004
25.924152577235226,-97.68234374999997
32.300311895879545,-117.54828125

The empty query ('') returns all matching airports.

var response = await client.SearchSingleIndexAsync<Hit>(
  "INDEX_NAME",
  new SearchParams(
    new SearchParamsObject
    {
      InsidePolygon = new List<List<Double>>
      {
        new List<Double>
        {
          42.01,
          -124.31,
          48.835509470063045,
          -124.40453125000005,
          45.01082951668149,
          -65.95726562500005,
          31.247243545293433,
          -81.06578125000004,
          25.924152577235226,
          -97.68234374999997,
          32.300311895879545,
          -117.54828125,
        },
      },
    }
  )
);

final response = await client.searchSingleIndex(
  indexName: "INDEX_NAME",
  searchParams: SearchParamsObject(
    insidePolygon: [
      [
        42.01,
        -124.31,
        48.835509470063045,
        -124.40453125000005,
        45.01082951668149,
        -65.95726562500005,
        31.247243545293433,
        -81.06578125000004,
        25.924152577235226,
        -97.68234374999997,
        32.300311895879545,
        -117.54828125,
      ],
    ],
  ),
);

response, err := client.SearchSingleIndex(client.NewApiSearchSingleIndexRequest(
  "INDEX_NAME").WithSearchParams(search.SearchParamsObjectAsSearchParams(
  search.NewEmptySearchParamsObject().SetInsidePolygon(
    [][]float64{
      {
        42.01,
        -124.31,
        48.835509470063045,
        -124.40453125000005,
        45.01082951668149,
        -65.95726562500005,
        31.247243545293433,
        -81.06578125000004,
        25.924152577235226,
        -97.68234374999997,
        32.300311895879545,
        -117.54828125,
      },
    }))))
if err != nil {
  // handle the eventual error
  panic(err)
}

SearchResponse response = client.searchSingleIndex(
  "INDEX_NAME",
  new SearchParamsObject().setInsidePolygon(
    Arrays.asList(
      Arrays.asList(
        42.01,
        -124.31,
        48.835509470063045,
        -124.40453125000005,
        45.01082951668149,
        -65.95726562500005,
        31.247243545293433,
        -81.06578125000004,
        25.924152577235226,
        -97.68234374999997,
        32.300311895879545,
        -117.54828125
      )
    )
  ),
  Hit.class
);

const response = await client.searchSingleIndex({
  indexName: 'indexName',
  searchParams: {
    insidePolygon: [
      [
        42.01, -124.31, 48.835509470063045, -124.40453125000005, 45.01082951668149, -65.95726562500005,
        31.247243545293433, -81.06578125000004, 25.924152577235226, -97.68234374999997, 32.300311895879545,
        -117.54828125,
      ],
    ],
  },
});

var response =
  client.searchSingleIndex(
    indexName = "INDEX_NAME",
    searchParams =
      SearchParamsObject(
        insidePolygon =
          listOf(
            listOf(
              42.01,
              -124.31,
              48.835509470063045,
              -124.40453125000005,
              45.01082951668149,
              -65.95726562500005,
              31.247243545293433,
              -81.06578125000004,
              25.924152577235226,
              -97.68234374999997,
              32.300311895879545,
              -117.54828125,
            )
          )
      ),
  )

$response = $client->searchSingleIndex(
    'INDEX_NAME',
    ['insidePolygon' => [
        [
            42.01,

            -124.31,

            48.835509470063045,

            -124.40453125000005,

            45.01082951668149,

            -65.95726562500005,

            31.247243545293433,

            -81.06578125000004,

            25.924152577235226,

            -97.68234374999997,

            32.300311895879545,

            -117.54828125,
        ],
    ],
    ],
);

response = client.search_single_index(
    index_name="INDEX_NAME",
    search_params={
        "insidePolygon": [
            [
                42.01,
                -124.31,
                48.835509470063045,
                -124.40453125000005,
                45.01082951668149,
                -65.95726562500005,
                31.247243545293433,
                -81.06578125000004,
                25.924152577235226,
                -97.68234374999997,
                32.300311895879545,
                -117.54828125,
            ],
        ],
    },
)

response = client.search_single_index(
  "INDEX_NAME",
  Algolia::Search::SearchParamsObject.new(
    inside_polygon: [
      [
        42.01,
        -124.31,
        48.835509470063045,
        -124.40453125000005,
        45.01082951668149,
        -65.95726562500005,
        31.247243545293433,
        -81.06578125000004,
        25.924152577235226,
        -97.68234374999997,
        32.300311895879545,
        -117.54828125
      ]
    ]
  )
)

val response = Await.result(
  client.searchSingleIndex(
    indexName = "INDEX_NAME",
    searchParams = Some(
      SearchParamsObject(
        insidePolygon = Some(
          Seq(
            Seq(42.01, -124.31, 48.835509470063045, -124.40453125000005, 45.01082951668149, -65.95726562500005,
              31.247243545293433, -81.06578125000004, 25.924152577235226, -97.68234374999997, 32.300311895879545,
              -117.54828125)
          )
        )
      )
    )
  ),
  Duration(100, "sec")
)

let response: SearchResponse<Hit> = try await client.searchSingleIndex(
    indexName: "INDEX_NAME",
    searchParams: SearchSearchParams.searchSearchParamsObject(SearchSearchParamsObject(insidePolygon: [[
        42.01,
        -124.31,
        48.835509470063045,
        -124.40453125000005,
        45.01082951668149,
        -65.95726562500005,
        31.247243545293433,
        -81.06578125000004,
        25.924152577235226,
        -97.68234374999997,
        32.300311895879545,
        -117.54828125,
    ]]))
)

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Filter results inside a polygon

Dataset

Initialize the client

Configure index settings

Filtering inside a polygonal area

​Dataset

​Initialize the client

​Configure index settings

​Filtering inside a polygonal area

Dataset

Initialize the client

Configure index settings

Filtering inside a polygonal area