Creating a filter for distance from a postal code using latitude and longitude fields, a postal code filter and a slider for distance

[ammarahw]

Hi, I am trying to create a slider for distance that would go from 1 to 100 miles. To set this up I have two variables, a filter, a measure for distance and a dimension to create the filter.

latitude variable:

=First({<postal_code = {"$(=GetFieldSelections(postal_code))"}>} lat)

longitude variable:

=First({<postal_code = {"$(=GetFieldSelections(postal_code))"}>} lon)

A filter called Postal Code that is just a drop down that lets you choose a postal code from the field postal_code.

The measure for distance is called Distance Between Zips and I wrote it like this:

sqrt(
(
(69.1 * (lat - (v_selected_lat))) * (69.1 * (lat - (v_selected_lat)))
) +
(
(69.1 * cos((v_selected_lat)) * (lon - (v_selected_lon))) * (69.1 * cos((v_selected_lat)) * (lon - (v_selected_lon)))
)
)

After that I created a dimension called Distance Filter which is this:

=if([Distance Between Zips] <= 5 , '5 Miles', 

if([Distance Between Zips] <= 10 , '10 Miles',

    if([Distance Between Zips] <=15 , '15 Miles',

        if([Distance Between Zips] <=20, '20 Miles', 

            if([Distance Between Zips] = 25, '25 Miles',

                if ([Distance Between Zips] <= 50, '50 Miles')

                  )

                 )

                )

               )

              )

At first I put the Distance Field into a drop down to see if it would work when I chose a zip code from the postal_code filter but it didn't work. The filter actually needs to be a slider.

Is there a better way to do what I am trying to do? I have been trying to piece together a process off of previous tickets like these:

https://community.qlik.com/t5/New-to-Qlik-Analytics/50-km-radius-in-qliksense-maps/td-p/1735868

https://community.qlik.com/t5/App-Development/Selecting-field-value-based-on-other-selection-field/t...

https://community.qlik.com/t5/QlikView-App-Dev/Show-distance-between-two-points/td-p/561286

[F_B]

Hi @ammarahw ,

there’s a more accurate way to calculate the distance between two points on the Earth using the Haversine formula, which is commonly used for this purpose:

=ACOS(
SIN(RADIANS(lat)) * SIN(RADIANS($(v_selected_lat))) +
COS(RADIANS(lat)) * COS(RADIANS($(v_selected_lat))) *
COS(RADIANS(lon) - RADIANS($(v_selected_lon)))
) * 3959

This formula calculates the great-circle distance between two points on a sphere given their longitudes and latitudes, and 3959 is the Earth's radius in miles.

Anyway, nice job! Hope this can help you improve your app.