An extension to the MKMapView class with an function to determine whether a region is valid and won't cause a crash if placed on a map.

ValidRegionMapViewExtension.swift

// to solve the invalid region <center:##.###, ##.### span:##.###, ##.###> issue
extension MKMapView {
    // determines if the region provided is in fact a valid region that can be shown on the map
    // notes: latitude          -> [-90, 90], !nan, !inf
    //        longitude         -> [-180, 180], !nan, !inf
    //        latitudeDelta     -> [0, 180], !nan, !inf
    //        longitudeDelta    -> [0, 360], !nan, !inf
    func canShow(region: MKCoordinateRegion) -> Bool {
        //.....center latitude
        return region.center.latitude != Double.infinity && region.center.latitude != Double.nan
            && region.center.latitude >= -90 && region.center.latitude <= 90
            // center longitude
            && region.center.longitude != Double.infinity && region.center.longitude != Double.nan
            && region.center.longitude >= -180 && region.center.longitude <= 180
            // span latitude delta
            && region.span.latitudeDelta != Double.infinity && region.span.latitudeDelta != Double.nan
            && region.span.latitudeDelta >= 0 && region.span.latitudeDelta <= 180
            // span longitude delta
            && region.span.longitudeDelta != Double.infinity && region.span.longitudeDelta != Double.nan
            && region.span.longitudeDelta >= 0 && region.span.longitudeDelta <= 360
    }
}