When you use this function in a query, it takes the latitude and longitude values in a dataset and returns information such as ISO 3166-1 alpha-3 codes or a country name based on the shapes available in the layer referenced in the query rule.

For more information on ISO 3166-1 alpha-3, see http://www.iso.org/iso/home/standards/country_codes.htm.

For more information on determining which layers are available, see Layers.

For more information on using query functions and operators in a REST API request, see Queries. For an end-to-end description of how to create a query, see Creating a Query.

The example below assumes the following dataset is in the system (a311282f85904f2bb59d3d1c81eeb962 in this case, but the ID is different for different accounts).

Lat;Lon;City
52.516667;13.383333;Berlin
41.836944;-87.684722;Chicago
39.916667;116.383333;Beijing

In this case, the example query creates a response with ISO-3 country codes based on the Lat, Lon values in the dataset.

{
  "facets": [
    "iso3"
  ],
  "version": 0.3,
  "namespace": {
    "iso3": {
      "source": [
        "lat",
        "lon"
      ],
      "apply": [
      {
        "params": [
        "here_country",
        "iso3"
        ],
      "type": "transform",
      "fn": "reverse_geocoding"
      }
    ]
    },
  },
  "dataset": "a311282f85904f2bb59d3d1c81eeb962"
}

When you submit the above request, the response includes an HTTP status code and the following JSON response body.

{
  "query": "339f0660252345129379a6e8f1380cfb",
  "kind": "datalens#query_result",
  "rows": [
    ["CHN"],
    ["USA"],
    ["DEU"]
  ],
  "columns": ["iso3"],
  "dataset": "a311282f85904f2bb59d3d1c81eeb962"
}

In this case, the params values specify that the layer here_country is used to determine the owning administrative entity of the geocoordinates defined by the latitude and longitude values. This layer provides country names, HERE IDs, and ISO 3166-1 alpha-3 country codes. If you changed the query above to the following query rule, then the response contains the country names.

{
  "facets": ["name"],
  "version": 0.3,
  "namespace": {
    "name": {
      "source": [
        "lat",
        "lon"
      ],
      "apply": [{
        "params": [
          "here_country",
          "name"
        ],
        "type": "transform",
        "fn": "reverse_geocoding"
      }]
    },
  },
  "dataset": "a311282f85904f2bb59d3d1c81eeb962"
}

{
  "query": "3eeebdd41c084ed08d6de6024f3056cb",
  "kind": "datalens#query_result",
  "rows": [
    ["United States"],
    ["Germany"],
    ["China"]
  ],
  "columns": ["name"],
  "dataset": "a311282f85904f2bb59d3d1c81eeb962"
}

For more information on the HTTP status codes, see HTTP Status Codes.

For more information on the elements in the JSON structure in the response body, see Query.