public async Task <IEnumerable <Place> > GetNearbyPlacesAsync(Geocode g, string keyword)
{
// from: https://developers.google.com/places/documentation/search
// e.g. https://maps.googleapis.com/maps/api/place/nearbysearch/xml?location=46,-122&rankby=distance&keyword=coffee&key=AddYourOwnKeyHere
string request = string.Format("https://maps.googleapis.com/maps/api/place/nearbysearch/xml?location={0},{1}&rankby=distance&keyword={2}&key={3}", g.Latitude, g.Longitude, keyword, GetGoogleApiKey());
var xml = await(new HttpClient()).GetStringAsync(request);
var results = XDocument.Parse(xml).Element("PlaceSearchResponse").Elements("result");
var places = new List <Place>();
foreach (var result in results)
{
var loc = result.Element("geometry").Element("location");
var icon = result.Element("icon").Value;
places.Add(new Place {
Name = result.Element("name").Value,
Icon = !string.IsNullOrWhiteSpace(icon) ? new Uri(icon) : null,
Vicinity = result.Element("vicinity").Value,
Location = new Geocode {
Latitude = double.Parse(loc.Element("lat").Value),
Longitude = double.Parse(loc.Element("lng").Value),
},
});
}
return(places);
}
public async Task <string> GetAddressForLocationAsync(Geocode loc)
{
// from https://developers.google.com/maps/documentation/geocoding/#ReverseGeocoding
// e.g. https://maps.googleapis.com/maps/api/geocode/xml?latlng=40.714224,-73.961452
string request = string.Format("https://maps.googleapis.com/maps/api/geocode/xml?latlng={0},{1}", loc.Latitude, loc.Longitude);
var xml = await(new HttpClient()).GetStringAsync(request);
var address = XDocument.Parse(xml).Element("GeocodeResponse").Element("result").Element("formatted_address").Value;
return(address);
}
public Geocode GetGreatCircleMidpoint(Geocode g1, Geocode g2)
{
// from http://stackoverflow.com/questions/6830959/c-sharp-find-midpoint-of-two-latitude-longitudes
// convert to radians
var dLon = deg2rad(g2.Longitude - g1.Longitude);
var lat1 = deg2rad(g1.Latitude);
var lat2 = deg2rad(g2.Latitude);
var lon1 = deg2rad(g1.Longitude);
// calculate the great circle midpoint
var Bx = Math.Cos(lat2) * Math.Cos(dLon);
var By = Math.Cos(lat2) * Math.Sin(dLon);
var lat3 = Math.Atan2(Math.Sin(lat1) + Math.Sin(lat2), Math.Sqrt((Math.Cos(lat1) + Bx) * (Math.Cos(lat1) + Bx) + By * By));
var lon3 = lon1 + Math.Atan2(By, Math.Cos(lat1) + Bx);
// convert to degrees
return(new Geocode {
Latitude = rad2deg(lat3),
Longitude = rad2deg(lon3),
});
}