/// <summary>
/// <para>Decodes a polyline from string into points as GPS Position as latitude (X) longitude (Y)</para>
/// <para>Source: https://github.com/mapbox/polyline/blob/master/src/polyline.js</para>
/// </summary>
/// <param name="encodedPolyline">Encoded polyline</param>
/// <param name="precisionFactor">Precision factor of the encoded polyline. Same as the one you encoded with if you encoded yourself.</param>
/// <returns>Points of the polyline as latitude, longitude</returns>
private static List <ProjVector2> DecodePoints(string encodedPolyline, double precisionFactor)
{
List <ProjVector2> points = new List <ProjVector2>();
int latitude = 0;
int longitude = 0;
for (int i = 0; i < encodedPolyline.Length;)
{
int b;
int shift = 0;
int result = 0;
do
{
b = encodedPolyline[i++] - 63;
result |= (b & 31) << shift;
shift += 5;
}while (32 <= b);
latitude += (result & 1) > 0 ? ~(result >> 1) : result >> 1;
result = shift = 0;
do
{
b = encodedPolyline[i++] - 63;
result |= (b & 31) << shift;
shift += 5;
}while (32 <= b);
longitude += (result & 1) > 0 ? ~(result >> 1) : result >> 1;
ProjVector2 p = new ProjVector2(latitude / precisionFactor, longitude / precisionFactor, Projection.LatitudeLongitude);
points.Add(p);
}
return(points);
}
public double?ProjectedDistance(ProjVector2 point, double distanceLimit)
{
point = point.ToProjection(Points.First().Projection);
int bestIndex = -1;
double bestProj = 0;
double bestDist = 0;
for (int i = 1; i < Points.Count; i++)
{
ProjVector2 a = Points[i] - Points[i - 1];
ProjVector2 b = point - Points[i - 1];
double proj = a.Dot(b) / a.LengthSquared;
if (proj < 0)
{
proj = 0;
}
else if (proj > 1)
{
proj = 1;
}
double dist = (point - (Points[i] + a * proj)).MeterLength / 1000;
if ((bestIndex == -1 || dist < bestDist) && dist < distanceLimit)
{
bestIndex = i;
bestProj = proj;
bestDist = dist;
}
}
// The point could not be projected
if (bestIndex == -1)
{
return(null);
}
double km = 0;
for (int i = 1; i <= bestIndex; i++)
{
km += (Points[i] - Points[i - 1]).MeterLength / 1000;
}
km += bestProj * (Points[bestIndex + 1] - Points[bestIndex]).MeterLength / 1000;
return(km);
}
private static List <PlacesAPIData> Scan(ProjVector2 position, double radius)
{
List <PlacesAPIData> ret = new List <PlacesAPIData>();
HttpWebRequest request = WebRequest.CreateHttp("https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=" + position.Vec.ToString() + "&radius=" + radius + "&type=train_station&key=" + APIKey);
request.Method = "GET";
try
{
using (WebResponse response = request.GetResponse())
{
using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
{
string json = reader.ReadToEnd();
JObject whole = JObject.Parse(json);
string status = whole["status"].ToString();
if (status == "OK" || status == "ZERO_RESULTS")
{
if (whole["results"] is JArray results)
{
foreach (JObject place in results)
{
ret.Add(new PlacesAPIData(
place["name"].ToString(),
new ProjVector2(double.Parse(place["geometry"]["location"]["lat"].ToString()), double.Parse(place["geometry"]["location"]["lng"].ToString()), Projection.LatitudeLongitude)));
}
}
}
else
{
throw new PlacesAPIException("Places API is unavailable. Status code: " + status);
}
}
}
}
catch (WebException)
{
// TODO: Log
throw new PlacesAPIException("Places API is unavailable.");
}
return(ret);
}
public static ProjVector2?Search(Station station, ProjVector2 position, double radius, int maxLevenshtein)
{
int minDist = 0;
PlacesAPIData?minRes = null;
var results = Scan(position.ToProjection(Projection.LatitudeLongitude), radius);
foreach (var result in results)
{
int dist = LevenshteinDistance(station.NormalizedName, Station.NormalizeName(result.StationName));
if (dist == 0)
{
return(result.Position);
}
if (dist <= maxLevenshtein && (minRes == null || dist < minDist))
{
minRes = result;
minDist = dist;
}
}
return(minRes?.Position);
}
public PlacesAPIData(string stationName, ProjVector2 position)
{
StationName = stationName;
Position = position;
}
