public void Test_FileFormat_HGT()
{
string fileName = "N43E005.hgt";
string sourceFile = Path.Combine("TestData", fileName + ".zip");
bool fileOk = File.Exists(sourceFile);
Assert.True(fileOk, "TestData is missing");
if (!File.Exists(fileName))
{
ZipFile.ExtractToDirectory(sourceFile, ".");
}
Assert.True(File.Exists(fileName), "Unzip failed.");
// Pass the full file name
fileName = Path.GetFullPath(fileName);
using (IRasterFile raster = _rasterService.OpenFile(fileName, DEMFileType.SRTM_HGT))
{
FileMetadata metaData = raster.ParseMetaData(new DEMFileDefinition(DEMFileType.SRTM_HGT, DEMFileRegistrationMode.Grid));
Assert.NotNull(metaData);
float elevation = raster.GetElevationAtPoint(metaData, 300, 10);
Assert.Equal(751f, elevation);
elevation = raster.GetElevationAtPoint(metaData, 10, 300);
Assert.Equal(297f, elevation);
}
}
public void Test_FileFormat_GeoTIFF()
{
string fileName = "N043E005_AVE_DSM.tif";
string sourceFile = Path.Combine("TestData", fileName + ".zip");
bool fileOk = File.Exists(sourceFile);
Assert.True(fileOk, "TestData is missing");
if (!File.Exists(fileName))
{
ZipFile.ExtractToDirectory(sourceFile, ".");
}
Assert.True(File.Exists(fileName), "Unzip failed.");
// Pass the full file name
fileName = Path.GetFullPath(fileName);
using (IRasterFile raster = _rasterService.OpenFile(fileName, DEMFileType.GEOTIFF))
{
FileMetadata metaData = raster.ParseMetaData(new DEMFileDefinition(DEMFileType.GEOTIFF, DEMFileRegistrationMode.Cell));
Assert.NotNull(metaData);
float elevation = raster.GetElevationAtPoint(metaData, 1000, 200);
Assert.Equal(304f, elevation);
elevation = raster.GetElevationAtPoint(metaData, 200, 1000);
Assert.Equal(95f, elevation);
}
}
public void Test_FileFormat_HGT_OutOfRange()
{
string fileName = "N43E005.hgt";
string sourceFile = Path.Combine("TestData", fileName + ".zip");
bool fileOk = File.Exists(sourceFile);
Assert.True(fileOk, "TestData is missing");
if (!File.Exists(fileName))
{
ZipFile.ExtractToDirectory(sourceFile, ".", true);
}
Assert.True(File.Exists(fileName), "Unzip failed.");
// Pass the full file name
fileName = Path.GetFullPath(fileName);
using (IRasterFile raster = _rasterService.OpenFile(fileName, DEMFileFormat.SRTM_HGT))
{
FileMetadata metaData = raster.ParseMetaData();
Assert.NotNull(metaData);
Assert.Throws <IndexOutOfRangeException>(() =>
{
float elevation = raster.GetElevationAtPoint(metaData, 10000, 10000);
});
// Expect exception
}
}
private float GetElevationAtPoint(RasterFileDictionary adjacentTiles, FileMetadata metadata, double lat, double lon, float lastElevation, IInterpolator interpolator)
{
float heightValue = 0;
try
{
IRasterFile mainRaster = adjacentTiles[metadata];
//const double epsilon = (Double.Epsilon * 100);
float noData = metadata.NoDataValueFloat;
// precise position on the grid (with commas)
double ypos = (lat - metadata.StartLat) / metadata.pixelSizeY;
double xpos = (lon - metadata.StartLon) / metadata.pixelSizeX;
// If pure integers, then it's on the grid
float xInterpolationAmount = (float)xpos % 1;
float yInterpolationAmount = (float)ypos % 1;
bool xOnGrid = Math.Abs(xInterpolationAmount) < float.Epsilon;
bool yOnGrid = Math.Abs(yInterpolationAmount) < float.Epsilon;
// If xOnGrid and yOnGrid, we are on a grid intersection, and that's all
if (xOnGrid && yOnGrid)
{
int x = (int)Math.Round(xpos, 0);
int y = (int)Math.Round(ypos, 0);
var tile = FindTile(metadata, adjacentTiles, x, y, out x, out y);
heightValue = mainRaster.GetElevationAtPoint(tile, x, y);
}
else
{
int xCeiling = (int)Math.Ceiling(xpos);
int xFloor = (int)Math.Floor(xpos);
int yCeiling = (int)Math.Ceiling(ypos);
int yFloor = (int)Math.Floor(ypos);
// Get 4 grid nearest points (DEM grid corners)
// If not yOnGrid and not xOnGrid we are on grid horizontal line
// We need elevations for top, bottom, left and right grid points (along x axis and y axis)
float northWest = GetElevationAtPoint(metadata, adjacentTiles, xFloor, yFloor, NO_DATA_OUT);
float northEast = GetElevationAtPoint(metadata, adjacentTiles, xCeiling, yFloor, NO_DATA_OUT);
float southWest = GetElevationAtPoint(metadata, adjacentTiles, xFloor, yCeiling, NO_DATA_OUT);
float southEast = GetElevationAtPoint(metadata, adjacentTiles, xCeiling, yCeiling, NO_DATA_OUT);
float avgHeight = GetAverageExceptForNoDataValue(noData, NO_DATA_OUT, southWest, southEast, northWest, northEast);
if (northWest == noData)
{
northWest = avgHeight;
}
if (northEast == noData)
{
northEast = avgHeight;
}
if (southWest == noData)
{
southWest = avgHeight;
}
if (southEast == noData)
{
southEast = avgHeight;
}
heightValue = interpolator.Interpolate(southWest, southEast, northWest, northEast, xInterpolationAmount, yInterpolationAmount);
}
if (heightValue == NO_DATA_OUT)
{
heightValue = lastElevation;
}
}
catch (Exception e)
{
_logger?.LogError(e, $"Error while getting elevation data : {e.Message}{Environment.NewLine}{e.ToString()}");
}
return(heightValue);
}
public float GetPointsElevation(IRasterFile raster, FileMetadata metadata, IEnumerable <GeoPoint> points, IInterpolator interpolator = null)
{
float heightValue = 0;
try
{
if (interpolator == null)
{
interpolator = GetInterpolator(InterpolationMode.Bilinear);
}
float noData = metadata.NoDataValueFloat;
foreach (var pointsByLat in points.GroupBy(p => p.Latitude))
{
double lat = pointsByLat.Key;
double ypos = (lat - metadata.StartLat) / metadata.pixelSizeY;
foreach (GeoPoint point in pointsByLat)
{
// precise position on the grid (with commas)
double lon = point.Longitude;
double xpos = (lon - metadata.StartLon) / metadata.pixelSizeX;
// If pure integers, then it's on the grid
float xInterpolationAmount = (float)xpos % 1;
float yInterpolationAmount = (float)ypos % 1;
bool xOnGrid = Math.Abs(xInterpolationAmount) < float.Epsilon;
bool yOnGrid = Math.Abs(yInterpolationAmount) < float.Epsilon;
// If xOnGrid and yOnGrid, we are on a grid intersection, and that's all
if (xOnGrid && yOnGrid)
{
int x = (int)Math.Round(xpos, 0);
int y = (int)Math.Round(ypos, 0);
heightValue = raster.GetElevationAtPoint(metadata, x, y);
}
else
{
int xCeiling = (int)Math.Ceiling(xpos);
int xFloor = (int)Math.Floor(xpos);
int yCeiling = (int)Math.Ceiling(ypos);
int yFloor = (int)Math.Floor(ypos);
// Get 4 grid nearest points (DEM grid corners)
// If not yOnGrid and not xOnGrid we are on grid horizontal line
// We need elevations for top, bottom, left and right grid points (along x axis and y axis)
float northWest = raster.GetElevationAtPoint(metadata, xFloor, yFloor);
float northEast = raster.GetElevationAtPoint(metadata, xCeiling, yFloor);
float southWest = raster.GetElevationAtPoint(metadata, xFloor, yCeiling);
float southEast = raster.GetElevationAtPoint(metadata, xCeiling, yCeiling);
float avgHeight = GetAverageExceptForNoDataValue(noData, NO_DATA_OUT, southWest, southEast, northWest, northEast);
if (Math.Abs(northWest - noData) < float.Epsilon)
{
northWest = avgHeight;
}
if (Math.Abs(northEast - noData) < float.Epsilon)
{
northEast = avgHeight;
}
if (Math.Abs(southWest - noData) < float.Epsilon)
{
southWest = avgHeight;
}
if (Math.Abs(southEast - noData) < float.Epsilon)
{
southEast = avgHeight;
}
heightValue = interpolator.Interpolate(southWest, southEast, northWest, northEast, xInterpolationAmount, yInterpolationAmount);
}
point.Elevation = heightValue;
}
}
}
catch (Exception e)
{
_logger?.LogError(e, $"Error while getting elevation data : {e.Message}{Environment.NewLine}{e.ToString()}");
}
return(heightValue);
}
private float GetElevationAtPoint(IRasterFile mainRaster, RasterFileDictionary adjacentTiles, FileMetadata metadata, double lat, double lon, float lastElevation, IInterpolator interpolator)
{
float heightValue = 0;
try
{
//const double epsilon = (Double.Epsilon * 100);
float noData = metadata.NoDataValueFloat;
double yPixel, xPixel, xInterpolationAmount, yInterpolationAmount;
// pixel coordinates interpolated
if (metadata.FileFormat.Registration == DEMFileRegistrationMode.Grid)
{
yPixel = Math.Sign(metadata.pixelSizeY) == 1 ?
(metadata.DataEndLat - lat) / metadata.pixelSizeY
: (lat - metadata.DataEndLat) / metadata.pixelSizeY;
xPixel = (lon - metadata.DataStartLon) / metadata.pixelSizeX;
// If at pixel center (ending by .5, .5), we are on the data point, so no need for adjacent raster checks
xInterpolationAmount = (double)(xPixel) % 1d;
yInterpolationAmount = (double)(yPixel) % 1d;
}
else
{
// In cell registration mode, the actual data point is at pixel center
// If at pixel center (ending by .5, .5), we are on the data point, so no need for adjacent raster checks
yPixel = Math.Sign(metadata.pixelSizeY) == 1 ?
((metadata.PhysicalEndLat + metadata.pixelSizeY / 2) - lat) / metadata.pixelSizeY
: (lat - (metadata.PhysicalEndLat + metadata.pixelSizeY / 2)) / metadata.pixelSizeY;
xPixel = (lon - (metadata.PhysicalStartLon + metadata.pixelSizeX / 2)) / metadata.pixelSizeX;
xInterpolationAmount = Math.Abs((double)(xPixel) % 1d);
yInterpolationAmount = Math.Abs((double)(yPixel) % 1d);
}
bool xOnDataPoint = Math.Abs(xInterpolationAmount) < EPSILON;
bool yOnDataPoint = Math.Abs(yInterpolationAmount) < EPSILON;
// If xOnGrid and yOnGrid, we are on a grid intersection, and that's all
// TODO fix that
// When cell registered, this true when interpolation is 0.5 / 0.5
// When grid registered, this is true
if (xOnDataPoint && yOnDataPoint)
{
int x = (int)Math.Round(xPixel, 0);
int y = (int)Math.Round(yPixel, 0);
var tile = FindTile(metadata, adjacentTiles, x, y, out x, out y);
heightValue = mainRaster.GetElevationAtPoint(tile, x, y);
}
else
{
int xCeiling = (int)Math.Ceiling(xPixel);
int xFloor = (int)Math.Floor(xPixel);
int yCeiling = (int)Math.Ceiling(yPixel);
int yFloor = (int)Math.Floor(yPixel);
// Get 4 grid nearest points (DEM grid corners)
// If not yOnGrid and not xOnGrid we are on grid horizontal line
// We need elevations for top, bottom, left and right grid points (along x axis and y axis)
float northWest = GetElevationAtPoint(metadata, adjacentTiles, xFloor, yFloor, noData);
float northEast = GetElevationAtPoint(metadata, adjacentTiles, xCeiling, yFloor, noData);
float southWest = GetElevationAtPoint(metadata, adjacentTiles, xFloor, yCeiling, noData);
float southEast = GetElevationAtPoint(metadata, adjacentTiles, xCeiling, yCeiling, noData);
float avgHeight = GetAverageExceptForNoDataValue(noData, NO_DATA_OUT, southWest, southEast, northWest, northEast);
if (northWest == noData)
{
northWest = avgHeight;
}
if (northEast == noData)
{
northEast = avgHeight;
}
if (southWest == noData)
{
southWest = avgHeight;
}
if (southEast == noData)
{
southEast = avgHeight;
}
heightValue = (float)interpolator.Interpolate(southWest, southEast, northWest, northEast, xInterpolationAmount, yInterpolationAmount);
}
if (heightValue == NO_DATA_OUT)
{
heightValue = lastElevation;
}
}
catch (Exception e)
{
_logger?.LogError(e, $"Error while getting elevation data : {e.Message}{Environment.NewLine}{e.ToString()}");
throw;
}
return(heightValue);
}