Elasticsearch geo search debug

gistfile1.as

// Create index with mapping
curl -XPUT http://192.168.0.10:9200/geotest/ -d '{
    "settings" : {
        "number_of_shards" : 1
    },
    "mappings" : {
        "places" : {
            "properties" : {
                "name" : { "type" : "string" },
                "location" : { "type" : "geo_point", "lat_lon": true }
            }
        }
    }
}'

// Insert test data
curl -XPUT http://192.168.0.10:9200/geotest/places/1 -d '{
    "name" : "closest",
    "location": "56.958344835,24.110908139"
}'
curl -XPUT http://192.168.0.10:9200/geotest/places/2 -d '{
    "name" : "average",
    "location": "56.9624382022,24.1378033877"
}'
curl -XPUT http://192.168.0.10:9200/geotest/places/3 -d '{
    "name" : "far",
    "location": "56.9440017845,24.117343883"
}'
curl -XPUT http://192.168.0.10:9200/geotest/places/4 -d '{
    "name" : "farthest",
    "location": "56.9428606076,24.077425299"
}'

// Do search
curl -XGET http://192.168.0.10:9200/geotest/places/_search?pretty=true -d '{
  "query": {
    "match_all": {}
  },
  "filter": {
    "geo_distance": {
      "distance": "3km",
      "distance_type": "arc",
      "location": {
        "lat": 56.959942,
        "lon": 24.113656
      }
    }
  },
  "sort": [
    {
      "_geo_distance": {
        "location": [
          56.959942,
          24.113656
        ],
        "order": "asc",
        "unit": "km"
      }
    }
  ],
  "fields": [
    "_source"
  ],
  "script_fields": {
    "distance": {
      "params": {
        "lat": 56.959942,
        "lon": 24.113656
      },
      "script": "doc[\u0027location\u0027].arcDistanceInKm(lat, lon)"
    }
  }
}'

How is it possible that sorting by _geo_distance ASC results shows in following order:

Pos	Name		Location			Distance
------|---------------|-------------------------------|-------------------
1	far		56.9440017845,24.117343883	1.7865229796151898
2	average		56.9624382022,24.1378033877	1.4899987260417218
3	closest		56.958344835,24.110908139	0.243505338088285
4	farthest	56.9428606076,24.077425299	2.9042299224497112



----------------
// Raw output
----------------

{ "hits" : { "hits" : [ { "_id" : "3",
        "_index" : "geotest",
        "_score" : null,
        "_source" : { "location" : "56.9440017845,24.117343883",
            "name" : "far"
          },
        "_type" : "places",
        "fields" : { "distance" : 1.7865229796151898 },
        "sort" : [ 4500.475587902285 ]
      },
      { "_id" : "2",
        "_index" : "geotest",
        "_score" : null,
        "_source" : { "location" : "56.9624382022,24.1378033877",
            "name" : "average"
          },
        "_type" : "places",
        "fields" : { "distance" : 1.4899987260417218 },
        "sort" : [ 4500.856454735725 ]
      },
      { "_id" : "1",
        "_index" : "geotest",
        "_score" : null,
        "_source" : { "location" : "56.958344835,24.110908139",
            "name" : "closest"
          },
        "_type" : "places",
        "fields" : { "distance" : 0.243505338088285 },
        "sort" : [ 4501.804913492201 ]
      },
      { "_id" : "4",
        "_index" : "geotest",
        "_score" : null,
        "_source" : { "location" : "56.9428606076,24.077425299",
            "name" : "farthest"
          },
        "_type" : "places",
        "fields" : { "distance" : 2.9042299224497112 },
        "sort" : [ 4502.240657295593 ]
      }
    ],
  "max_score" : null,
  "total" : 4
} }