Distance and Bearing: Difference between revisions

Content added Content deleted

Inline

Revision as of 06:24, 9 October 2022

It is very important in aviation to have knowledge of the nearby airports at any time in flight.

Task

Determine the distance and bearing from an Airplane to the 20 nearest Airports whenever requested. Use the non-commercial data from openflights.org airports.dat as reference.

A request comes from an airplane at position ( latitude, longitude ): ( 51.514669, 2.198581 ).

Your report should contain the following information from table airports.dat (column shown in brackets):

Name(2), Country(4), ICAO(6), Distance and Bearing calculated from Latitude(7) and Longitude(8).

Distance is measured in nautical miles (NM). Resolution is 0.1 NM.

Bearing is measured in degrees (°). 0° = 360° = north then clockwise 90° = east, 180° = south, 270° = west. Resolution is 1°.

See

openflights.org/data: Airport, airline and route data
Movable Type Scripts: Calculate distance, bearing and more between Latitude/Longitude points

Julia

using DataFrames
using CSV

const EARTH_RADIUS_KM = 6372.8
const TASK_CONVERT_NM = 0.0094174
const AIRPORT_DATA_FILE = "airports.dat.txt"

const QUERY = (latitude =  51.514669, longitude = 2.198581)

"""
Given two latitude, longitude pairs in degrees for two points on the Earth,
get distance (nautical miles) and initial direction of travel (degrees)
for travel from lat1, lon1 to lat2, lon2
"""
function haversine(lat1, lon1, lat2, lon2)
    dlat = lat2 - lat1
    dlon = lon2 - lon1
    a = sind(dlat / 2)^2 + cosd(lat1) * cosd(lat2) * sind(dlon / 2)^2
    c = 2.0 * asind(sqrt(a))
    theta = atand(sind(dlon) * cosd(lat2),
        cosd(lat1) * sind(lat2) - sind(lat1) * cosd(lat2) * cosd(dlon))
    theta = (theta + 360) % 360
    return EARTH_RADIUS_KM * c * TASK_CONVERT_NM, theta
end

""" Given latitude and longitude, find `wanted` closest airports in database file csv. """
function find_nearest_airports(latitude, longitude, wanted = 20, csv = AIRPORT_DATA_FILE)
    airports = DataFrame(CSV.File(csv))[:, [2, 4, 6, 7, 8]]
    airports[!, "d"] .= 0.0
    airports[!, "b"] .= 0
    rename!(airports, [:Name, :Country, :ICAO, :Latitude_deg, :Longitude_deg, :Distance, :Bearing])
    for r in eachrow(airports)
        distance, bearing = haversine(latitude, longitude, r.Latitude_deg, r.Longitude_deg)
        r.Distance, r.Bearing = round(distance, digits = 1), Int(round(bearing))
    end
    sort!(airports, :Distance)
    return airports[1:wanted, [:Name, :Country, :ICAO, :Distance, :Bearing]]
end

println(find_nearest_airports(QUERY.latitude, QUERY.longitude))

Output:

20×5 DataFrame
 Row │ Name                               Country         ICAO     Distance  Bearing 
     │ String                             String          String7  Float64   Int64   
─────┼───────────────────────────────────────────────────────────────────────────────
   1 │ Koksijde Air Base                  Belgium         EBFN         30.6      146 
   2 │ Ostend-Bruges International Airp…  Belgium         EBOS         31.3      127 
   3 │ Kent International Airport         United Kingdom  EGMH         33.5      252 
   4 │ Calais-Dunkerque Airport           France          LFAC         34.4      196 
   5 │ Westkapelle heliport               Belgium         EBKW         42.6      105 
   6 │ Lympne Airport                     United Kingdom  EGMK         51.6      240 
   7 │ Ursel Air Base                     Belgium         EBUL         52.8      114 
   8 │ Southend Airport                   United Kingdom  EGMC         56.2      274 
   9 │ Merville-Calonne Airport           France          LFQT         56.3      163 
  10 │ Wevelgem Airport                   Belgium         EBKT         56.4      137 
  11 │ Midden-Zeeland Airport             Netherlands     EHMZ         57.2       90 
  12 │ Lydd Airport                       United Kingdom  EGMD         58.0      235 
  13 │ RAF Wattisham                      United Kingdom  EGUW         59.0      309 
  14 │ Beccles Airport                    United Kingdom  EGSM         59.3      339 
  15 │ Lille/Marcq-en-Baroeul Airport     France          LFQO         59.7      146 
  16 │ Lashenden (Headcorn) Airfield      United Kingdom  EGKH         62.2      250 
  17 │ Le Touquet-Côte d'Opale Airport    France          LFAT         63.7      200
  18 │ Rochester Airport                  United Kingdom  EGTO         64.2      262
  19 │ Lille-Lesquin Airport              France          LFQQ         66.2      149
  20 │ Thurrock Airfield                  United Kingdom  EGMT         68.4      272

Phix

without js -- file i/o
enum Airport_ID, Name, City, Country, IATA, ICAO, Latitude, Longitude, Altitude, Timezone, DST, Tz_Olson, Type, Source
function tabulate(sequence s)
    s = split(trim(s),"\n")
    for i,ri in s do
        ri = split(ri,',')
        if length(ri)!=14 then
            ri[2] &= ","&ri[3]
            ri[3..3] = {}
        end if
        for j in {Airport_ID, Latitude, Longitude, Altitude} do
            ri[j] = to_number(ri[j])
        end for
        for j in {Name,City,Country,ICAO} do
            ri[j] = trim(ri[j],`"`)
        end for
        s[i] = ri
    end for
    return s    
end function

constant airports = tabulate(get_text("airports.dat"))

function distance(atom lat1, lon1, lat2, lon2, integer units)
    atom dist = 0
    if lat1!=lat2 or lon1!=lon2 then
        atom radlat1 = lat1*PI/180,
             radlat2 = lat2*PI/180,
             radtheta = (lon1-lon2)*PI/180
        dist = sin(radlat1)*sin(radlat2) + cos(radlat1)*cos(radlat2)*cos(radtheta)
        dist = arccos(min(dist,1))*180/PI * 60*1.1515576 -- in Statute Miles
        if units = 'K' then dist *= 1.609344 end if     -- in Kilometres
        if units = 'N' then dist *= 0.868976 end if    -- in Nautical Miles
    end if
    return dist
end function

function bearing(atom lat1, lon1, lat2, lon2)
    atom bear = NULL
    if lat1!=lat2 or lon1!=lon2 then
        atom radlat1 = lat1*PI/180,
             radlat2 = lat2*PI/180,
             raddlon = (lon2-lon1)*PI/180,
             y = sin(raddlon)*cos(radlat2),
             x = cos(radlat1)*sin(radlat2) - sin(radlat1)*cos(radlat2)*cos(raddlon)
        bear = remainder(atan2(y, x)*180/PI+360,360)
    end if
    return bear;
end function

procedure query(atom lat,lon, integer rows=20)
    sequence r = {}
    for a in airports do
        atom lat2 = a[Latitude],
             lon2 = a[Longitude],
             dist = round(distance(lat,lon,lat2,lon2,'N'),10),
             bear = round(bearing(lat,lon,lat2,lon2))
        r = append(r,{a[Name],a[Country],a[ICAO],dist,bear})
    end for
    r = sort_columns(r,{4})[1..rows]
    printf(1,"                Name                 |    Country     | ICAO | Distance in NM | Bearing in ° \n")
    printf(1,"-------------------------------------+----------------+------+----------------+--------------\n")
    printf(1,"%s\n",{join(r,"\n",fmt:=" %-36s| %-15s| %4s |           %4.1f |          %3d")})
    printf(1,"(%d rows)\n",rows)
end procedure

query(51.514669, 2.198581)

Output:

                Name                 |    Country     | ICAO | Distance in NM | Bearing in ° 
-------------------------------------+----------------+------+----------------+--------------
 Koksijde Air Base                   | Belgium        | EBFN |           30.7 |          146
 Ostend-Bruges International Airport | Belgium        | EBOS |           31.3 |          127
 Kent International Airport          | United Kingdom | EGMH |           33.5 |          252
 Calais-Dunkerque Airport            | France         | LFAC |           34.4 |          196
 Westkapelle heliport                | Belgium        | EBKW |           42.6 |          105
 Lympne Airport                      | United Kingdom | EGMK |           51.6 |          240
 Ursel Air Base                      | Belgium        | EBUL |           52.8 |          114
 Southend Airport                    | United Kingdom | EGMC |           56.2 |          274
 Merville-Calonne Airport            | France         | LFQT |           56.4 |          163
 Wevelgem Airport                    | Belgium        | EBKT |           56.5 |          137
 Midden-Zeeland Airport              | Netherlands    | EHMZ |           57.3 |           90
 Lydd Airport                        | United Kingdom | EGMD |           58.0 |          235
 RAF Wattisham                       | United Kingdom | EGUW |           59.0 |          309
 Beccles Airport                     | United Kingdom | EGSM |           59.3 |          339
 Lille/Marcq-en-Baroeul Airport      | France         | LFQO |           59.7 |          146
 Lashenden (Headcorn) Airfield       | United Kingdom | EGKH |           62.2 |          250
 Le Touquet-Côte d'Opale Airport     | France         | LFAT |           63.7 |          200
 Rochester Airport                   | United Kingdom | EGTO |           64.2 |          262
 Lille-Lesquin Airport               | France         | LFQQ |           66.2 |          149
 Thurrock Airfield                   | United Kingdom | EGMT |           68.4 |          272
(20 rows)

SQL/PostgreSQL

Create table and copy from URL.

-- create table airports with 14 columns
CREATE TABLE airports (
    Airport_ID serial PRIMARY KEY,
    Name VARCHAR NOT NULL,
    City VARCHAR,
    Country VARCHAR NOT NULL,
    IATA VARCHAR,
    ICAO VARCHAR,
    Latitude double precision NOT NULL,
    Longitude double precision NOT NULL,
    Altitude SMALLINT,
    Timezone VARCHAR,
    DST VARCHAR,
    Tz_Olson VARCHAR,
    Type VARCHAR,
    Source VARCHAR
);   

-- copy CSV airports.dat from URL 
COPY airports FROM 
PROGRAM 'curl "https://raw.githubusercontent.com/jpatokal/openflights/master/data/airports.dat"' 
WITH (FORMAT csv);

Functions for distance and bearing.

-- calculate distance
CREATE OR REPLACE FUNCTION calculate_distance(lat1 float, lon1 float, lat2 float, lon2 float, units varchar)
RETURNS numeric AS $dist$
    DECLARE
        dist float = 0;
        radlat1 float;
        radlat2 float;
        theta float;
        radtheta float;
    BEGIN
        IF lat1 = lat2 AND lon1 = lon2
            THEN RETURN dist;
        ELSE
            radlat1 = pi() * lat1 / 180;
            radlat2 = pi() * lat2 / 180;
            theta = lon1 - lon2;
            radtheta = pi() * theta / 180;
            dist = sin(radlat1) * sin(radlat2) + cos(radlat1) * cos(radlat2) * cos(radtheta);

            IF dist > 1 THEN dist = 1; END IF;

            dist = acos(dist);
            dist = dist * 180 / pi();

            -- Distance in Statute Miles
            dist = dist * 60 * 1.1515576; 
            
            -- Distance in Kilometres
            IF units = 'K' THEN dist = dist * 1.609344; END IF;

            -- Distance in Nautical Miles
            IF units = 'N' THEN dist = dist * 0.868976; END IF;

            dist = dist::numeric;
            RETURN dist;
        END IF;
    END;
$dist$ LANGUAGE plpgsql;


-- calculate bearing
CREATE OR REPLACE FUNCTION calculate_bearing(lat1 float, lon1 float, lat2 float, lon2 float)
RETURNS numeric AS $bear$
    DECLARE
        bear float = NULL;
        radlat1 float;
        radlat2 float;
        raddlon float;
        y float;
        x float;
        
    BEGIN
        IF lat1 = lat2 AND lon1 = lon2
            THEN RETURN bear;
        ELSE
            radlat1 = pi() * lat1 / 180;
            radlat2 = pi() * lat2 / 180;
            raddlon = pi() * (lon2 - lon1) / 180;

            y = sin(raddlon) * cos(radlat2);
            x = cos(radlat1) * sin(radlat2) - sin(radlat1) * cos(radlat2) * cos(raddlon);
            
            bear = atan2(y, x) * 180 / pi();
            bear = (bear::numeric + 360) % 360;
       
            RETURN bear;
        END IF;
    END;
$bear$ LANGUAGE plpgsql;

Request from airplane at position ( 51.514669, 2.198581 ).

Select 
   Name "Name",
   Country "Country",
   ICAO "ICAO",
   ROUND(calculate_distance(51.514669, 2.198581, Latitude, Longitude, 'N'), 1) "Distance in NM",
   ROUND(calculate_bearing(51.514669, 2.198581, Latitude, Longitude), 0) "Bearing in °"
From 
    airports
ORDER BY "Distance in NM"
LIMIT 20;

Output:

                Name                 |    Country     | ICAO | Distance in NM | Bearing in ° 
-------------------------------------+----------------+------+----------------+--------------
 Koksijde Air Base                   | Belgium        | EBFN |           30.7 |          146
 Ostend-Bruges International Airport | Belgium        | EBOS |           31.3 |          127
 Kent International Airport          | United Kingdom | EGMH |           33.5 |          252
 Calais-Dunkerque Airport            | France         | LFAC |           34.4 |          196
 Westkapelle heliport                | Belgium        | EBKW |           42.6 |          105
 Lympne Airport                      | United Kingdom | EGMK |           51.6 |          240
 Ursel Air Base                      | Belgium        | EBUL |           52.8 |          114
 Southend Airport                    | United Kingdom | EGMC |           56.2 |          274
 Merville-Calonne Airport            | France         | LFQT |           56.4 |          163
 Wevelgem Airport                    | Belgium        | EBKT |           56.5 |          137
 Midden-Zeeland Airport              | Netherlands    | EHMZ |           57.3 |           90
 Lydd Airport                        | United Kingdom | EGMD |           58.0 |          235
 RAF Wattisham                       | United Kingdom | EGUW |           59.0 |          309
 Beccles Airport                     | United Kingdom | EGSM |           59.3 |          339
 Lille/Marcq-en-Baroeul Airport      | France         | LFQO |           59.7 |          146
 Lashenden (Headcorn) Airfield       | United Kingdom | EGKH |           62.2 |          250
 Le Touquet-Côte d'Opale Airport     | France         | LFAT |           63.7 |          200
 Rochester Airport                   | United Kingdom | EGTO |           64.2 |          262
 Lille-Lesquin Airport               | France         | LFQQ |           66.2 |          149
 Thurrock Airfield                   | United Kingdom | EGMT |           68.4 |          272
(20 rows)

Wren

Translation of: SQL

Library: Wren-dynamic

Library: Wren-fmt

However, rather than use Wren-sql, we program it so that it can be run from Wren-CLI. Runtime is about 0.24 seconds.

import "io" for File
import "./dynamic" for Tuple
import "./fmt" for Fmt

var airportFields = [
    "airportID",
    "name",
    "city",
    "country",
    "iata",
    "icao",
    "latitude",
    "longitude",
    "altitude",
    "timezone",
    "dst",
    "tzOlson",
    "type",
    "source"
]
var Airport = Tuple.create("Airport", airportFields)

var fileName = "airports.dat" // local copy
var lines = File.read(fileName).trimEnd().split("\n")
var lc = lines.count
var airports = List.filled(lc, null)
for (i in 0...lc) {
    var fields    = lines[i].split(",").map { |f| f.replace("\"", "") }.toList
    if (fields.count == 15) {  // airport name has an embedded comma
        fields[1] = fields[1] + "," + fields[2]
        for (i in 2..13) fields[i] = fields[i+1]
    }
    var airportID = Num.fromString(fields[0])
    var name      = fields[1]
    var city      = fields[2]
    var country   = fields[3]
    var iata      = fields[4]
    var icao      = fields[5]
    var latitude  = Num.fromString(fields[6])
    var longitude = Num.fromString(fields[7])
    var altitude  = Num.fromString(fields[8])
    var timezone  = fields[9]
    var dst       = fields[10]
    var tzOlson   = fields[11]
    var type      = fields[12]
    var source    = fields[13]
    airports[i]   = Airport.new(airportID, name, city, country, iata, icao, latitude, longitude,
                                altitude, timezone, dst, tzOlson, type, source)
}

var calculateDistance = Fn.new { |lat1, lon1, lat2, lon2, units|
    if (lat1 == lat2 && lon1 == lon2) return 0
    var radlat1 = Num.pi * lat1 / 180
    var radlat2 = Num.pi * lat2 / 180
    var theta = lon1 - lon2
    var radtheta = Num.pi * theta / 180
    var dist = radlat1.sin * radlat2.sin + radlat1.cos * radlat2.cos * radtheta.cos
    if (dist > 1) dist = 1
    dist = dist.acos * 180 / Num.pi * 60 * 1.1515576  // distance in statute miles
    if (units == "K") dist = dist * 1.609344          // distance in kilometers
    if (units == "N") dist = dist * 0.868976          // distance in nautical miles
    return dist
}

var calculateBearing = Fn.new { |lat1, lon1, lat2, lon2|
    if (lat1 == lat2 && lon1 == lon2) return 0
    var radlat1 = Num.pi * lat1 / 180
    var radlat2 = Num.pi * lat2 / 180
    var raddlon = Num.pi * (lon2 - lon1) / 180
    var y = raddlon.sin * radlat2.cos
    var x = radlat1.cos * radlat2.sin - radlat1.sin * radlat2.cos * raddlon.cos
    var bear = y.atan(x) * 180 / Num.pi
    return (bear + 360) % 360
}

// request from airplane at position (51.514669, 2.198581)
var query = List.filled(airports.count, null)
for (i in 0...airports.count) {
    var a = airports[i]    
    var dist = calculateDistance.call(51.514669, 2.198581, a.latitude, a.longitude, "N")
    dist = (dist * 10).round / 10
    var bear = calculateBearing.call(51.514669, 2.198581, a.latitude, a.longitude).round
    query[i] = [a.name, a.country, a.icao, dist, bear]
}
query.sort { |q1, q2| q1[3] < q2[3] }
System.print("                Name                 |    Country     | ICAO | Distance in NM | Bearing in ° ")
System.print("-------------------------------------+----------------+------+----------------+--------------")
var fmt = " $-36s| $-15s| $4s |           $4.1f |          $3d"
for (i in 0..19) Fmt.lprint(fmt, query[i])
System.print("(20 rows)")

Output:

                Name                 |    Country     | ICAO | Distance in NM | Bearing in ° 
-------------------------------------+----------------+------+----------------+--------------
 Koksijde Air Base                   | Belgium        | EBFN |           30.7 |          146
 Ostend-Bruges International Airport | Belgium        | EBOS |           31.3 |          127
 Kent International Airport          | United Kingdom | EGMH |           33.5 |          252
 Calais-Dunkerque Airport            | France         | LFAC |           34.4 |          196
 Westkapelle heliport                | Belgium        | EBKW |           42.6 |          105
 Lympne Airport                      | United Kingdom | EGMK |           51.6 |          240
 Ursel Air Base                      | Belgium        | EBUL |           52.8 |          114
 Southend Airport                    | United Kingdom | EGMC |           56.2 |          274
 Merville-Calonne Airport            | France         | LFQT |           56.4 |          163
 Wevelgem Airport                    | Belgium        | EBKT |           56.5 |          137
 Midden-Zeeland Airport              | Netherlands    | EHMZ |           57.3 |           90
 Lydd Airport                        | United Kingdom | EGMD |           58.0 |          235
 RAF Wattisham                       | United Kingdom | EGUW |           59.0 |          309
 Beccles Airport                     | United Kingdom | EGSM |           59.3 |          339
 Lille/Marcq-en-Baroeul Airport      | France         | LFQO |           59.7 |          146
 Lashenden (Headcorn) Airfield       | United Kingdom | EGKH |           62.2 |          250
 Le Touquet-Côte d'Opale Airport     | France         | LFAT |           63.7 |          200
 Rochester Airport                   | United Kingdom | EGTO |           64.2 |          262
 Lille-Lesquin Airport               | France         | LFQQ |           66.2 |          149
 Thurrock Airfield                   | United Kingdom | EGMT |           68.4 |          272