I would like to know a Swift library or method that I can use to convert from 4326 to 3857. I have referred some libraries such as Proj4Swift and Proj.4, but to no avail. The first link does not has a workable download and the second does not has a documentation. Would anyone suggest a library or method that I can use to achieve this in Swift?

I have also referred other similar questions but could not find a proper solution.


1 Answer 1


Well, since I couldn't find a clear and direct answer, I wrote the code in Swift, by referring the following and this. It's as follows.

func getCoordinatesInEPSG3857(longitudeInEPSG4326: Double, latitudeInEPSG4326: Double) -> (Double, Double) {
    let longitudeInEPSG3857 = (longitudeInEPSG4326 * 20037508.34 / 180)
    let latitudeInEPSG3857 = (log(tan((90 + latitudeInEPSG4326) * Double.pi / 360)) / (Double.pi / 180)) * (20037508.34 / 180)

    return (longitudeInEPSG3857, latitudeInEPSG3857)

Here, you can pass the coordinates which are in EPSG:4326 and the function returns the coordinates in EPSG:3857.

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