Hi @jhwang ,



You can use Math operation to do this.

---

Hi @Shashi,



I tried to calculate the distance between two coordinates, but I failed.



Here is my code:



Qualtrics.SurveyEngine.addOnReady(function()

{



var R = 6371;

var t1_dx = parseFloat("${e://Field/t1_dx}");

var t1_ox = parseFloat("${e://Field/t1_ox}");

var t1_dy = parseFloat("${e://Field/t1_dy}");

var t1_oy = parseFloat("${e://Field/t1_oy}");





var latDistance = Math.toRadians(t1_dx - t1_ox);

var lonDistance = Math.toRadians(t1_dy - t1_oy);

var a = Math.sin(latDistance / 2) * Math.sin(latDistance / 2)

+ Math.cos(Math.toRadians(t1_ox)) * Math.cos(Math.toRadians(t1_dx))

* Math.sin(lonDistance / 2) * Math.sin(lonDistance / 2);

var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

var distance = (R * c * 1000) / 1609.344; // convert to miles



var height = 0.00;



var distance2 = Math.pow(distance, 2) + Math.pow(height, 2);



var dist1 = Math.sqrt(distance2);



Qualtrics.SurveyEngine.setEmbeddedData("dist1", dist1);

});





Could you or anyone please correct my code?



Thank you very much.

---

Hi @jhwang



Please use the below code:



function getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) {

var R = 6371; // Radius of the earth in km

var dLat = deg2rad(lat2-lat1); // deg2rad below

var dLon = deg2rad(lon2-lon1);

var a =

Math.sin(dLat/2) * Math.sin(dLat/2) +

Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *

Math.sin(dLon/2) * Math.sin(dLon/2)

;

var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

var d = R * c; // Distance in km

return d;

}



function deg2rad(deg) {

return deg * (Math.PI/180)

}

---

@Shashi,



Thank you for your suggestion. But I still cannot see the embedded data value of the distance.



Here is my code:



Qualtrics.SurveyEngine.addOnReady(function()

{

var R = 6371;

var lat2 = Number("${e://Field/t1_dx}");

var lat1 = Number("${e://Field/t1_ox}");

var lon2 = Number("${e://Field/t1_dy}");

var lon1 = Number("${e://Field/t1_oy}");



function getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) {

var R = 6371; // Radius of the earth in km

var dLat = deg2rad(lat2-lat1); // deg2rad below

var dLon = deg2rad(lon2-lon1);

var a =

Math.sin(dLat/2) * Math.sin(dLat/2) +

Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *

Math.sin(dLon/2) * Math.sin(dLon/2)

;

var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

var d = R * c; // Distance in km

return d;

}



function deg2rad(deg) {

return deg * (Math.PI/180)

}



Qualtrics.SurveyEngine.setEmbeddedData("dist1", d);



});



Here is more detailed information of variables:

* Coordinates of origin: (`t1_ox`, `t1_oy`)

* Coordinates of destination: (`t1_dx`, `t1_dy`)



I checked if the embedded data of `t1_ox` ~ `t1_dy` work, and confirmed that they have no issues.



However, I cannot see the embedded data of `dist1`.



Thank you.

---

> @jhwang said:

> @Shashi,

>

> Thank you for your suggestion. But I still cannot see the embedded data value of the distance.

>

> Here is my code:

>

> Qualtrics.SurveyEngine.addOnReady(function()

> {

> var R = 6371;

> var lat2 = Number("${e://Field/t1_dx}");

> var lat1 = Number("${e://Field/t1_ox}");

> var lon2 = Number("${e://Field/t1_dy}");

> var lon1 = Number("${e://Field/t1_oy}");

>

> function getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) {

> var R = 6371; // Radius of the earth in km

> var dLat = deg2rad(lat2-lat1); // deg2rad below

> var dLon = deg2rad(lon2-lon1);

> var a =

> Math.sin(dLat/2) * Math.sin(dLat/2) +

> Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *

> Math.sin(dLon/2) * Math.sin(dLon/2)

> ;

> var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

> var d = R * c; // Distance in km

> return d;

> }

>

> function deg2rad(deg) {

> return deg * (Math.PI/180)

> }

>

> Qualtrics.SurveyEngine.setEmbeddedData("dist1", getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) );

>

> });

>

> Here is more detailed information of variables:

> * Coordinates of origin: (`t1_ox`, `t1_oy`)

> * Coordinates of destination: (`t1_dx`, `t1_dy`)

>

> I checked if the embedded data of `t1_ox` ~ `t1_dy` work, and confirmed that they have no issues.

>

> However, I cannot see the embedded data of `dist1`.

>

> Thank you.



Change the last line to:



`Qualtrics.SurveyEngine.setEmbeddedData("dist1", getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) ); `



Hope you have created an embedded data dist1 in the survey flow before this question

---