CODEWITHSUNDEEP
c#wpfbing-mapsbezier
David Soler
David Soler

Reputation: 190

How can I draw a bezier curve polyline on a bing map wpf c#?

Bing maps library for wpf seems not to include any helper to draw a bezier curve. It has MapPolyLine which can be used to draw straight lines between n points. Any solution?

Thanks

Upvotes: 0

Views: 656

Answers (3)

Graeme Baillie
Graeme Baillie

Reputation: 11

I was stuck using WPF and VS Basic and no available Google API or Microsoft Maps API to allow me to draw a geodesic curve representing a flight from A to B. Found reference [1] which provided the maths for the answer.

    Public Function GetGeodesicPath(startLocation As Location, endLocation As Location, segments As Integer) As LocationCollection
    Dim lc As New LocationCollection
    lc.Add(startLocation)

    ' Convert coordinates from degrees to Radians
    Dim lat1 = startLocation.Latitude * Math.PI / 180
    Dim lon1 = startLocation.Longitude * Math.PI / 180
    Dim lat2 = endLocation.Latitude * Math.PI / 180
    Dim lon2 = endLocation.Longitude * Math.PI / 180

    ' Calculate the length of the route
    Dim length = 2 * Math.Asin(Math.Sqrt(Math.Pow((Math.Sin((lat1 - lat2) / 2)), 2) + Math.Cos(lat1) * Math.Cos(lat2) * Math.Pow((Math.Sin((lon1 - lon2) / 2)), 2)))

    ' Calculate positions at fixed intervals along the route - 32 segments to provide a smooth curve

    For counter = 1 To segments

        Dim segmentlength = (counter / segments)
        Dim A = Math.Sin((1 - segmentlength) * length) / Math.Sin(length)
        Dim B = Math.Sin(segmentlength * length) / Math.Sin(length)

        ' Obtain 3D cartesian co-ordinates of each point

        Dim x = A * Math.Cos(lat1) * Math.Cos(lon1) + B * Math.Cos(lat2) * Math.Cos(lon2)
        Dim y = A * Math.Cos(lat1) * Math.Sin(lon1) + B * Math.Cos(lat2) * Math.Sin(lon2)
        Dim z = A * Math.Sin(lat1) + B * Math.Sin(lat2)

        Dim segmentLat = Math.Atan2(z, Math.Sqrt(Math.Pow(x, 2) + Math.Pow(y, 2)))
        Dim segmentLon = Math.Atan2(y, x)

        ' Create a Location by converting lat lon to degrees
        Dim location As New Location
        location.Latitude = segmentLat / (Math.PI / 180)
        location.Longitude = segmentLon / (Math.PI / 180)

        ' Add location to Location Collection
        lc.Add(location)

    Next

    Return lc

End Function

This returns a locationCollection which can be added to your mapPolyline

Upvotes: 0

rbrundritt
rbrundritt

Reputation: 17954

Alternatively to using geodesic, if you don't care about being spatially accurate you can take your coordinates, convert them to pixel coordinates at zoom level 19 using the code here: https://msdn.microsoft.com/en-us/library/bb259689.aspx

Then pass the pixel coordinates through a standard Bezier curve algorithm. Take the resulting values and convert them back to locations.

Upvotes: 0

George Dzhgarkava
George Dzhgarkava

Reputation: 56

Bing Maps does not support curved geometries directly, so instead can approximate the shape of a curved line by creating a polyline containing several small segments.

Hope this article will help https://alastaira.wordpress.com/2011/06/27/geodesics-on-bing-maps-v7/

Upvotes: 0

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