latlong-pair-dist.json

{
    "name": "Lat/Long Distance between a pair of points",
    "description": "Extends a dataset with the distance in meters between pairs of lat/long fields.",
    "inputs": [
        {
            "name": "dataset-in",
            "type": "dataset-id",
            "description": "Dataset for extending with distance calculation."
        },
        {
            "name": "latA-field",
            "type": "string",
            "description": "The name/id of the latitude A field."
        },
        {
            "name": "longA-field",
            "type": "string",
            "description": "The name/id of the longitude A field."
        },
        {
            "name": "latB-field",
            "type": "string",
            "description": "The name/id of the latitude B field."
        },
        {
            "name": "longB-field",
            "type": "string",
            "description": "The name/id of the longitude B field."
        }
    ],
    "outputs": [
        {
            "name": "dataset-out",
            "type": "dataset-id",
            "description": "The ID of the extended dataset"
        }
    ]
}

latlong-pair-dist.whizzml

; Computes the distance between pairs of lat/long coordinates.
; All lat/long coordinates must be in signed degrees (no N/W/S/E etc)
(define (latlong-pair-dist dataset-in latA-field longA-field latB-field longB-field) 
  (create-and-wait-dataset {
    "origin_dataset" dataset-in 
    "new_fields" [ 
       {
        "field" ( flatline "( let ("
          "R 6371000 "
          "latA (to-radians ( field {{latA-field}}) )"
          "latB (to-radians ( field {{latB-field}}) )"          
          "latD ( - latB latA ) "
          "longD ( to-radians ( - ( field {{longA-field}} ) ( field {{longB-field}} ) ) )"
          "a ( + ( square ( sin ( / latD 2 ) ) ) ( * (cos latA) (cos latB) (square ( sin ( / longD 2))) ) ) "
          "c ( * 2 ( asin ( min (list 1 (sqrt a)) ) ) ) ) " 
          "( * R c ) )" )
        "name" "Distance (m)"
       }
      ]
    }
  )
)

(define dataset-out (latlong-pair-dist dataset-in latA-field longA-field latB-field longB-field))