Sort by nested Geo distance properties - elasticsearch

Question

I'm trying to sort by geo distance an index with nested geo point mapping.
Here is my simplified mapping :
'organizations' => [
'_doc' => [
'properties' => [
'locations' => [
'type' => 'nested',
'properties' => [
'point' => [
'type' => 'geo_point',
'ignore_malformed' => true
]
]
]
]
]
]
Here, each organizations can have several locations point.
Documents :
PUT /organizations ,
[
{
name: "A",
locations: [
{
point: {
lat: 1.5,
lon: 2
}
},
{
point: {
lat: 1,
lon: 0
}
}
]
},
{
name: "B",
locations: [
{
point: {
lat: 4.2,
lon: 3
}
}
]
},
{
name: "C",
locations: [
{
point: {
lat: 0.4,
lon: 1
}
}
]
}
];
Here is my query (PHP array):
[
"query" => [
"query_string" => [
"query" => "*"
]
]
"sort" => [
0 => [
"_geo_distance" => [
"locations.point" => "1, 0.1"
"order" => "asc"
"unit" => "km"
"nested_path" => "locations"
]
]
]
]
expected result :
1 => name : A
2 => name : C
3 => bame : B
I'd like to get resources ordered by geo_point (check each location, and then check if a location is close to the given lat / lon )

Answer 1

You can meet your goal using function_score.
For example with the query like:
note: code is in js;
"_geo_distance": {
"place.location.geo.coordinates": [
this._geo.lon,
this._geo.lat
],
"order": "asc",
"unit": "km",
"distance_type": "plane"
}
Then in function_score add script_score
function_score["script_score"] = {
"script": {
"source": `1000/doc['place.location.geo.coordinates'].planeDistance(${this._geo.lat},${this._geo.lon}) `
}
The original function_score is like:
'function_score': {
"score_mode": "multiply",
'query': {
"dis_max": {
"tie_breaker": 0.7,
"boost": 1.9,
"queries": this._query
},
},
'boost': 0.06,
'boost_mode': 'sum',
}