Sorting Array Results

Question

I have an array which is produced on the success event of an ajax request. The array obtained from the ajax request looks like this:

Array:

            [{
                "locationID": "9",
                "locationName": "Employee Residence",
                "locationLatitude": "34.47189",
                "locationLongitude": "-111.9896046999",
            }, {
                "locationID": "40",
                "locationName": "Tron Utah",
                "locationLatitude": "33.964212",
                "locationLongitude": "-118.3783589999",

            }, {
                "locationID": "39",
                "locationName": "Tron Enterprises",
                "locationLatitude": "33.735187",
                "locationLongitude": "-111.9579499999",

            }]

Calculations are performed on this array which provides a list of locations and their distance from the users current location. I would like to sort the results by distance; my code is as follows:

Jquery:

// Success
success: function (data) {
    // Obtain Log/Lat
    navigator.geolocation.getCurrentPosition(function(position) {
        // Obtain Current Position Lat/Lon
        glbVar.latitude = position.coords.latitude;
        glbVar.longitude = position.coords.longitude;
        // Console Log
        //console.log('Lat: ' + glbVar.latitude + ' Lon: ' + glbVar.longitude);
        // Index Location Return Data
        for (var index = 0; index < data.length; index++) {
            // Items
            var item = data[index];
            // Obtain Location Details
            varLocationDetails[index] = {"Location Position": {"Longitude": item.locationLongitude, "Latitude": item.locationLatitude, "Location": item.locationName}};
            // Each Location Detail
            $.each(varLocationDetails[index], function (a,b) {
                // Each Locations Distance (From Users Current Location)
                varLocationsDistance = calculateDistance(glbVar.longitude, glbVar.latitude, b.Longitude, b.Latitude);
                // Determine Locations Radius
                if (varLocationsDistance <= varLocationRadius) {
                    // Determine Distance For Each Location
                    varDistanceObject[varInt] = {distance: varLocationsDistance, location: b.Location};
                    // Sort by Distance
                    //varDistanceObject[varInt].sort(function(a,b) {
                    //  return parseInt(a.distance) - parseInt(b.distance)
                    //});
                    // Console Log
                    //console.log(varDistanceObject[varInt]);
                    // Obtain Location Name/Distance
                    varLocation = b.Location;
                    varDistance = calculateDistance(glbVar.longitude, glbVar.latitude, b.Longitude, b.Latitude);
                    // Obtain Function Return
                    functionReturn = '<li>' + varLocation + ': ' + varDistance + 'm</li>';
                    // Console Log
                    //console.log(functionReturn);
                    // Function Return
                    $('#groups').append(functionReturn);// Append to HTML
                };
                // Increment
                ++varInt;
            });
        }
    });
}

Distance Calculation

            // Calculate Distance
            function calculateDistance(varLongitude, varLatitude, varLon, varLat) {
                // Assign Radius
                varRadius = 6371;
                // Obtain Lon/Lat Values
                varLongitude = varLongitude * (Math.PI / 180);
                varLatitude = varLatitude * (Math.PI / 180);
                varLon = varLon * (Math.PI / 180);
                varLat = varLat * (Math.PI / 180);
                // 1st  X/Y Axis
                x0 = varLongitude * varRadius * Math.cos(varLatitude);
                y0 = varLatitude * varRadius;
                // 2nd X/Y Axis
                x1 = varLon * varRadius * Math.cos(varLat);
                y1 = varLat * varRadius;
                // Calculate Values
                dx = x0 - x1;
                dy = y0 - y1;
                // Determine Distance
                d = Math.sqrt((dx * dx) + (dy * dy));
                // Function Return
                return Math.round(d * 1000);
            };

Current Results:

Residence: 0m
Tron Utah: 532559m
Tron Enterprises: 45358m

Desired Results:

Residence: 0m
Tron Enterprises: 45358m
Tron Utah: 532559m

The "Sort by Distance" portion of the code is commented out because it doesn't work. Any assistance to correct this code or provide an alternative method is appreciated. I am a self taught amateur web developer.

Thanks,

Have have added that portion of the code to the question. :) — notyou61
– notyou61, Commented Aug 18, 2014 at 14:56

dreamlab · Accepted Answer · 2014-08-18 15:05:50Z

3

first insert all your distance values into your data array. so you have the data like this:

    {
        "locationID": "9",
        "locationName": "Employee Residence",
        "locationLatitude": "34.47189",
        "locationLongitude": "-111.9896046999",
        "distance": 45456
    }

this is done by iterating over the given data like this:

for ( var i = 0; i < data.length; i++ ) {
    var entry = data[i];
    entry.distance = calculateDistance(entry.locationLongitude, entry.locationLatitude, LOCAL_LON, LOCAL_LAT);
}

sort your data by the distance property.

var sortedData = data.sort(function(a, b) {
    return a.distance - b.distance;
});

you will now have an array sorted by distance

iterate through the sorted array and create your html representation

edited Aug 18, 2014 at 15:05

answered Aug 18, 2014 at 14:50

dreamlab

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3 Comments

notyou61 Over a year ago

The distance is calculated based on the locations lat/lon which is produced from the ajax call. How to sort after this is obtained is where I am lost.

dreamlab Over a year ago

do you have the data prepared like in step 1?

notyou61 Over a year ago

The distance will be a dynamic value based on the users current location. The only data available is what is shown in the array portion of the question.

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