/// <summary>
/// Fetch the Image Tile from given Tile Server <see cref="TileServer" />
/// </summary>
/// <param name = "SourceTile">Source Tile <see cref="Tile"/></param>
/// <param name = "SourceTileServer">The source Tile Server where Tile Images would be grabbed from <see cref="TileServer"/></param>
/// <param name = "Subdomain">Subdomain of Source Tile Server to get the image from <see cref="TileServer" /></param>
/// <param name = "Zoom">Zoom Level <see href="http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Zoom_levels" /> </param>
/// <param name = "XOffset">(Optional) Image Offest in the X-Axis (e.g. Use 1 if you want to retrieve the tile image above the Source Tile <see cref="Tile"/></param>
/// <param name = "YOffset">(Optional) Image Offest in the Y-Axis (e.g. Use 1 if you want to retrieve the tile image to the right of the Source Tile <see cref="Tile"/> </param>
/// <param name = "Timeout">(Optional) Optional timeout in milliseconds /> </param>
/// <returns>Tile Image as a Byte Array</returns>
public static byte[] FetchTile(Tile SourceTile, TileServer SourceTileServer, char Subdomain,
int Zoom = 0, short XOffset = 0, short YOffset = 0, int Timeout = 10000)
{
var tileUri = GetTileUri(SourceTileServer, Subdomain, Zoom, (int)(SourceTile.X) + XOffset, (int)(SourceTile.Y) + YOffset);
var tileRequest = (HttpWebRequest)WebRequest.Create(tileUri);
tileRequest.UseDefaultCredentials = true;
System.Diagnostics.Debug.WriteLine(tileRequest.RequestUri.ToString());
try
{
using (var serverResponse = GetSyncResponse(tileRequest, Timeout))
{
if (serverResponse == null)
{
throw (new WebException("Error fetching tile from: " + tileUri.OriginalString, null));
}
else
{
if (serverResponse.ContentType.StartsWith("image", StringComparison.OrdinalIgnoreCase))
{
using (Stream responseStream = serverResponse.GetResponseStream())
{
return(ReadFully(responseStream));
}
}
else
{
throw (new WebException("Error fetching tile from: " + tileUri.OriginalString + Environment.NewLine
+ "Instead of an image tile, the following content type " + Environment.NewLine
+ "was returned instead: " + serverResponse.ContentType + Environment.NewLine
+ (serverResponse.ContentType.StartsWith("text", StringComparison.OrdinalIgnoreCase) ?
ReadAllText(serverResponse.GetResponseStream()) : "")
, null));
}
}
}
}
catch (Exception ex)
{
throw (new WebException("Error fetching tile from: " + tileUri.OriginalString + Environment.NewLine +
ex.Message, null));
}
}
/// <summary>
/// Creates a Tile Cache in MBTiles v1.1 Format <see href="https://github.com/mapbox/mbtiles-spec" />
/// from a given Bounding Box (SouthEast Lat/Lon, NorthWest Lat/Lon, Minimum Zoom and Maximum Zoom)
/// </summary>
/// <param name = "SourceTileServer">The source Tile Server where Tile Images would be grabbed from <see cref="TileServer"/></param>
/// <param name = "SqlConnection">A valid SQLiteConnection based on the SQLite PCL-Net</param>
/// <param name = "SELat">Latitude of SouthEast corner of map extent</param>
/// <param name = "SELon">Longitude of SouthEast corner of map extent</param>
/// <param name = "NWLat">Latitude of NorthWest corner of map extent</param>
/// <param name = "NWLon">Longitude of NorthWest corner of map extent</param>
/// <param name = "MinZoom">Minimum map Zoom Level</param>
/// <param name = "MaxZoom">(Optional) Maximum map Zoom Level</param>
/// <returns>Generates an MBTiles File in the specified SQLiteConnection</returns>
public static void CreateTileCache(TileServer SourceTileServer, SQLiteConnection SqlConnection,
float SELat, float SELon, float NWLat, float NWLon,
ushort MinZoom, ushort MaxZoom = 100)
{
// Calculate Maximum Zoom Level
if (MaxZoom > SourceTileServer.MaxZoom)
{
MaxZoom = SourceTileServer.MaxZoom;
}
// Check for valid Zoom Level
if (MinZoom > MaxZoom)
{
throw new Exception("Minimum Zoom should be less than Maximum Zoom");
}
// Get number of subdomains for given Tile Server
int s = 0; // Define starting subdomain
int sMax = SourceTileServer.Subdomains.Count() - 1;
// Setup SQLite Connection
SQLiteCommand sqlCommand;
string sql;
// Create Metadata Table
sql = "CREATE TABLE metadata (name text, value text)";
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
// Create Tiles Table
sql = "CREATE TABLE tiles (zoom_level integer, tile_column integer, tile_row integer, tile_data blob)";
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
// Insert Required Metadata
sql = "INSERT INTO metadata VALUES ('name','Test')";
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
sql = "INSERT INTO metadata VALUES ('type','baselayer')";
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
sql = "INSERT INTO metadata VALUES ('version','1')";
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
sql = "INSERT INTO metadata VALUES ('description','Test Tileset')";
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
sql = string.Format("INSERT INTO metadata VALUES ('format','{0}')", SourceTileServer.imgFormat);
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
sql = string.Format("INSERT INTO metadata VALUES ('bounds','{0},{1},{2},{3}')", float.Parse(SELon.ToString(), CultureInfo.InvariantCulture),
float.Parse(SELat.ToString(), CultureInfo.InvariantCulture),
float.Parse(NWLon.ToString(), CultureInfo.InvariantCulture),
float.Parse(NWLat.ToString(), CultureInfo.InvariantCulture));
sqlCommand = SqlConnection.CreateCommand(sql);
sqlCommand.ExecuteNonQuery();
// Iteration Sequence: Bottom-Left (SE) to Top-Right (NW), from lowest Zoom Level to Highest Zoom Level
// Iterate through all Zoom Levels (from lowest/zoomed-out to highest/zoomed-in)
int zoomLevels = MaxZoom - MinZoom;
int zoomLevel = MinZoom;
for (int z = 0; z <= zoomLevels; z++)
{
// Set Zoom
zoomLevel = MinZoom + z;
System.Diagnostics.Debug.WriteLine("Zoom: " + zoomLevel.ToString());
// Get minimum Tile X, Y values
OSMCoordinate MinTMS = GetOSMCoordinates(SELat, SELon, zoomLevel);
// Get maximum Tile X, Y values
OSMCoordinate MaxTMS = GetOSMCoordinates(NWLat, NWLon, zoomLevel);
// Iterate through all Rows (Y-Axis)
int numOfRows = MinTMS.Y - MaxTMS.Y;
for (int y = 0; y <= numOfRows; y++)
{
System.Diagnostics.Debug.WriteLine("Row: " + (MinTMS.Y - y).ToString());
// Retrieve tiles from Left to Right (X-Axis)
int numOfTiles = MaxTMS.X - MinTMS.X;
for (int x = 0; x <= numOfTiles; x++)
{
// Fetch Tile
System.Diagnostics.Debug.WriteLine("X: {0} Y: {1} Zoom: {2}",
(MinTMS.X + x).ToString(), (MinTMS.Y - y).ToString(), zoomLevel.ToString());
// Check subdomain to retrieve from
if (s > sMax)
{
s = 0;
}
Tile tile = new Tile(MinTMS.X + x, MinTMS.Y - y);
byte[] tileBytes = FetchTile(tile, SourceTileServer, SourceTileServer.Subdomains[s], zoomLevel);
s++;
// Insert into database
sqlCommand.CommandText = "INSERT INTO tiles (zoom_level, tile_column, tile_row, tile_data) VALUES (@zoom,@x,@y,@image)";
sqlCommand.Bind("@zoom", zoomLevel);
sqlCommand.Bind("@x", MinTMS.X + x);
sqlCommand.Bind("@y", ((1 << zoomLevel) - (MinTMS.Y - y) - 1));
sqlCommand.Bind("@image", tileBytes);
sqlCommand.ExecuteNonQuery();
}
}
}
// Close SQL Connection
SqlConnection.Close();
}
/// <summary>
/// Creates the URI for a requested Tile
/// </summary>
/// <param name="Tile">The Slippy Map Tile<see cref="Tile"/></param>
/// <returns>The URI that will be used for the web request.</returns>
public static Uri GetTileUri(TileServer tileServer, char subdomain, int zoom, int x, int y)
{
string url = string.Format(tileServer.UriFormat, subdomain, zoom.ToString(), x.ToString(), y.ToString(), tileServer.imgFormat);
return(new Uri(url.ToString()));
}
