/// <summary>
/// Load in all the SRTM files to create a virtual map
/// </summary>
private void BuildVirtualMap()
{
int start_lat = (int)Math.Floor(settings.StartLatitude);
int end_lat = (int)(settings.StartLatitude + ((settings.ImageHeight * settings.PixelWidthInMetres) / 111320.0) + 0.5);
int start_lon = (int)Math.Floor(settings.StartLongitude);
double width_in_metres = settings.PixelWidthInMetres * settings.ImageWidth;
double met = SRTM.GetMetresPerDegreeLongitude(start_lat);
int width1 = (int)(width_in_metres / met);
met = SRTM.GetMetresPerDegreeLongitude(end_lat);
int width2 = (int)(width_in_metres / met);
width1 = Math.Max(width1, width2);
int LonWidth = width1 + 2;
double height_in_metres = settings.PixelWidthInMetres * settings.ImageHeight;
int LatHeight = (int)(height_in_metres / 111320.0) + 1;
Map = new SRTM[LonWidth, LatHeight];
for (int i = 0; i < LatHeight; i++)
{
for (int j = 0; j < LonWidth; j++)
{
Map[j, i] = new SRTM(start_lat - i, start_lon + j, SRTMdirectory);
}
}
}
/// <summary>
/// Work out the needed SRTM files and download them
/// </summary>
private void GetSRTMFiles()
{
int start_lat = (int)Math.Floor(settings.StartLatitude);
int start_lon = (int)Math.Floor(settings.StartLongitude);
double met = SRTM.GetMetresPerDegreeLongitude(start_lat);
double width_in_metres = settings.PixelWidthInMetres * settings.ImageWidth;
int LonWidth = (int)(width_in_metres / met) + 2;
double height_in_metres = settings.PixelWidthInMetres * settings.ImageHeight;
int LatHeight = (int)(height_in_metres / 111320.0) + 1;
for (int i = 0; i < LatHeight; i++)
{
for (int j = 0; j < LonWidth; j++)
{
RequiredFiles.Add(SRTM.GetFileName(start_lat - i, start_lon + j));
}
}
UpdateMainDisplay(1);
// Remove any files we already have
downloadstatus = "Removing existing files";
for (int i = RequiredFiles.Count - 1; i >= 0; i--)
{
String fn = System.IO.Path.Combine(SRTMdirectory, RequiredFiles[i]);
fn += ".hgt";
if (File.Exists(fn))
{
RequiredFiles.RemoveAt(i);
UpdateMainDisplay(1);
}
}
downloadstatus = "Downloading files";
UpdateMainDisplay(1);
ThreadStart childref = new ThreadStart(DownloadFiles);
Thread childThread = new Thread(childref);
childThread.IsBackground = true;
childThread.Start();
}