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BlueSky's avatar
BlueSky
Helper I
5 years ago
Solved

Can I use this Python function for each row of a tabe ?

I have a table called Activity, there is a coloum called Polyline.
For each polyline I want to return it's corresponding longatude and lattitude cordinates.

 

A polyline is a way of encoding a series of cordinates as a string. There algorithm to do this is described here:
https://developers.google.com/maps/documentation/utilities/polylinealgorithm

 

I have found a Python script and function which converts a polyline into a list of longatude and lattitude cordinates:

 

 

# This function is free of any dependencies.
def decode_polyline(polyline_str):
    '''Pass a Google Maps encoded polyline string; returns list of lat/lon pairs'''
    index, lat, lng = 0, 0, 0
    coordinates = []
    changes = {'latitude': 0, 'longitude': 0}

    # Coordinates have variable length when encoded, so just keep
    # track of whether we've hit the end of the string. In each
    # while loop iteration, a single coordinate is decoded.
    while index < len(polyline_str):
        # Gather lat/lon changes, store them in a dictionary to apply them later
        for unit in ['latitude', 'longitude']: 
            shift, result = 0, 0

            while True:
                byte = ord(polyline_str[index]) - 63
                index += 1
                result |= (byte & 0x1f) << shift
                shift += 5
                if not byte >= 0x20:
                    break

            if (result & 1):
                changes[unit] = ~(result >> 1)
            else:
                changes[unit] = (result >> 1)

        lat += changes['latitude']
        lng += changes['longitude']

        coordinates.append((lat / 100000.0, lng / 100000.0))

    return coordinates

 

 

Borrowed from here https://github.com/geodav-tech/decode-google-maps-polyline


Is it possible to use this Python funciton in PowerBI and pass the polyline for each Activity and return it's coordinates?

  • Hi BlueSky ,

     

    Try to transform the data in Power Query with Python script, then create visuals.

     

    Best regards,
    Lionel Chen

    If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

     

     

     

     

1 Reply

  • v-lionel-msft's avatar
    v-lionel-msft
    Community Support

    Hi BlueSky ,

     

    Try to transform the data in Power Query with Python script, then create visuals.

     

    Best regards,
    Lionel Chen

    If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.