public HeightMap GetHeightMap(FileMetadata metadata)
{
HeightMap heightMap = new HeightMap(metadata.Width, metadata.Height);
heightMap.Count = heightMap.Width * heightMap.Height;
var coords = new List <GeoPoint>(heightMap.Count);
// metadata.BitsPerSample
// When 16 we have 2 bytes per sample
// When 32 we have 4 bytes per sample
int bytesPerSample = metadata.BitsPerSample / 8;
byte[] byteScanline = new byte[metadata.ScanlineSize];
for (int y = 0; y < metadata.Height; y++)
{
TiffFile.ReadScanline(byteScanline, y);
double latitude = metadata.StartLat + (metadata.pixelSizeY * y);
for (int x = 0; x < metadata.Width; x++)
{
double longitude = metadata.StartLon + (metadata.pixelSizeX * x);
float heightValue = 0;
switch (metadata.SampleFormat)
{
case RasterSampleFormat.FLOATING_POINT:
heightValue = BitConverter.ToSingle(byteScanline, x * metadata.BitsPerSample / 8);
break;
case RasterSampleFormat.INTEGER:
heightValue = BitConverter.ToInt16(byteScanline, x * metadata.BitsPerSample / 8);
break;
case RasterSampleFormat.UNSIGNED_INTEGER:
heightValue = BitConverter.ToUInt16(byteScanline, x * metadata.BitsPerSample / 8);
break;
default:
throw new Exception("Sample format unsupported.");
}
if (heightValue < 32768)
{
heightMap.Minimum = Math.Min(metadata.MinimumAltitude, heightValue);
heightMap.Maximum = Math.Max(metadata.MaximumAltitude, heightValue);
}
else
{
heightValue = 0;
}
coords.Add(new GeoPoint(latitude, longitude, heightValue));
}
}
heightMap.Coordinates = coords;
return(heightMap);
}
public float GetElevationAtPoint(FileMetadata metadata, int x, int y)
{
float heightValue = 0;
try
{
if (this.IsTiled)
{
// TODO store in metadata
int tileWidth = this.TileWidth;
int tileHeight = this.TileHeight;
int tileSize = this.TileSize;
byte[] buffer;
var tileX = (x / tileWidth) * tileWidth;
var tileY = (y / tileHeight) * tileHeight;
if (tilesCache == null)
{
tilesCache = new Dictionary <int, byte[]>();
}
var tileKey = (x / tileWidth) + (y / tileHeight) * (metadata.Width / tileWidth + 1);
if (!tilesCache.TryGetValue(tileKey, out buffer))
{
buffer = new byte[tileSize];
TiffFile.ReadTile(buffer, 0, tileX, tileY, 0, 0);
tilesCache.Add(tileKey, buffer);
}
var offset = x - tileX + (y - tileY) * tileHeight;
heightValue = GetElevationAtPoint(metadata, offset, buffer);
}
else
{
// metadata.BitsPerSample
// When 16 we have 2 bytes per sample
// When 32 we have 4 bytes per sample
int bytesPerSample = metadata.BitsPerSample / 8;
byte[] byteScanline = new byte[metadata.ScanlineSize];
TiffFile.ReadScanline(byteScanline, y);
heightValue = GetElevationAtPoint(metadata, x, byteScanline);
}
}
catch (Exception e)
{
throw new Exception($"Error in ParseGeoDataAtPoint: {e.Message}");
}
return(heightValue);
}
public float ParseGeoDataAtPoint(FileMetadata metadata, int x, int y)
{
float heightValue = 0;
try
{
byte[] scanline = new byte[metadata.ScanlineSize];
ushort[] scanline16Bit = new ushort[metadata.ScanlineSize / 2];
TiffFile.ReadScanline(scanline, y);
Buffer.BlockCopy(scanline, 0, scanline16Bit, 0, scanline.Length);
heightValue = ParseGeoDataAtPoint(metadata, x, scanline16Bit);
}
catch (Exception e)
{
throw new Exception($"Error in ParseGeoDataAtPoint: {e.Message}");
}
return(heightValue);
}
public float GetElevationAtPoint(FileMetadata metadata, int x, int y)
{
float heightValue = 0;
try
{
// metadata.BitsPerSample
// When 16 we have 2 bytes per sample
// When 32 we have 4 bytes per sample
int bytesPerSample = metadata.BitsPerSample / 8;
byte[] byteScanline = new byte[metadata.ScanlineSize];
TiffFile.ReadScanline(byteScanline, y);
heightValue = GetElevationAtPoint(metadata, x, byteScanline);
}
catch (Exception e)
{
throw new Exception($"Error in ParseGeoDataAtPoint: {e.Message}");
}
return(heightValue);
}
public HeightMap ParseGeoDataInBBox(BoundingBox bbox, FileMetadata metadata, float noDataValue = 0)
{
// metadata.BitsPerSample
// When 16 we have 2 bytes per sample
// When 32 we have 4 bytes per sample
int bytesPerSample = metadata.BitsPerSample / 8;
byte[] byteScanline = new byte[metadata.ScanlineSize];
int yStart = (int)Math.Floor((bbox.yMax - metadata.StartLat) / metadata.pixelSizeY);
int yEnd = (int)Math.Ceiling((bbox.yMin - metadata.StartLat) / metadata.pixelSizeY);
int xStart = (int)Math.Floor((bbox.xMin - metadata.StartLon) / metadata.pixelSizeX);
int xEnd = (int)Math.Ceiling((bbox.xMax - metadata.StartLon) / metadata.pixelSizeX);
xStart = Math.Max(0, xStart);
xEnd = Math.Min(metadata.Width - 1, xEnd);
yStart = Math.Max(0, yStart);
yEnd = Math.Min(metadata.Height - 1, yEnd);
HeightMap heightMap = new HeightMap(xEnd - xStart + 1, yEnd - yStart + 1);
heightMap.Count = heightMap.Width * heightMap.Height;
var coords = new List <GeoPoint>(heightMap.Count);
heightMap.BoundingBox = new BoundingBox(0, 0, 0, 0);
for (int y = yStart; y <= yEnd; y++)
{
TiffFile.ReadScanline(byteScanline, y);
double latitude = metadata.StartLat + (metadata.pixelSizeY * y);
// bounding box
if (y == yStart)
{
heightMap.BoundingBox.yMax = latitude;
heightMap.BoundingBox.xMin = metadata.StartLon + (metadata.pixelSizeX * xStart);
heightMap.BoundingBox.xMax = metadata.StartLon + (metadata.pixelSizeX * xEnd);
}
else if (y == yEnd)
{
heightMap.BoundingBox.yMin = latitude;
}
for (int x = xStart; x <= xEnd; x++)
{
double longitude = metadata.StartLon + (metadata.pixelSizeX * x);
float heightValue = 0;
switch (metadata.SampleFormat)
{
case "IEEEFP":
heightValue = BitConverter.ToSingle(byteScanline, x * bytesPerSample);
break;
case "INT":
heightValue = BitConverter.ToInt16(byteScanline, x * bytesPerSample);
break;
case "UINT":
heightValue = BitConverter.ToUInt16(byteScanline, x * bytesPerSample);
break;
default:
throw new Exception("Sample format unsupported.");
}
if (heightValue < 32768)
{
heightMap.Mininum = Math.Min(heightMap.Mininum, heightValue);
heightMap.Maximum = Math.Max(heightMap.Maximum, heightValue);
}
else
{
heightValue = (float)noDataValue;
}
coords.Add(new GeoPoint(latitude, longitude, heightValue, x, y));
}
}
Debug.Assert(heightMap.Width * heightMap.Height == coords.Count);
heightMap.Coordinates = coords;
return(heightMap);
}
public HeightMap GetHeightMapInBBox(BoundingBox bbox, FileMetadata metadata, float noDataValue = 0)
{
int yStart = 0;
int yEnd = 0;
int xStart = 0;
int xEnd = 0;
if (metadata.FileFormat.Registration == DEMFileRegistrationMode.Grid)
{
yStart = (int)Math.Floor((bbox.yMax - metadata.PhysicalEndLat) / metadata.pixelSizeY);
yEnd = (int)Math.Ceiling((bbox.yMin - metadata.PhysicalEndLat) / metadata.pixelSizeY);
xStart = (int)Math.Floor((bbox.xMin - metadata.PhysicalStartLon) / metadata.pixelSizeX);
xEnd = (int)Math.Ceiling((bbox.xMax - metadata.PhysicalStartLon) / metadata.pixelSizeX);
}
else
{
yStart = (int)Math.Floor((bbox.yMax - metadata.DataEndLat) / metadata.pixelSizeY);
yEnd = (int)Math.Ceiling((bbox.yMin - metadata.DataEndLat) / metadata.pixelSizeY);
xStart = (int)Math.Floor((bbox.xMin - metadata.DataStartLon) / metadata.pixelSizeX);
xEnd = (int)Math.Ceiling((bbox.xMax - metadata.DataStartLon) / metadata.pixelSizeX);
}
// Tiled geotiffs like aster have overlapping 1px borders
int overlappingPixel = this.IsTiled ? 1 : 0;
xStart = Math.Max(0, xStart);
xEnd = Math.Min(metadata.Width - 1, xEnd) - overlappingPixel;
yStart = Math.Max(0, yStart);
yEnd = Math.Min(metadata.Height - 1, yEnd) - overlappingPixel;
HeightMap heightMap = new HeightMap(xEnd - xStart + 1, yEnd - yStart + 1);
heightMap.Count = heightMap.Width * heightMap.Height;
var coords = new List <GeoPoint>(heightMap.Count);
heightMap.BoundingBox = new BoundingBox(0, 0, 0, 0);
if (this.IsTiled)
{
// Tiled rasters are composed of multiple "sub" images
// TODO store in metadata
int tileWidth = this.TileWidth;
int tileHeight = this.TileHeight;
int tileSize = this.TileSize;
byte[] buffer;
for (int y = yStart; y <= yEnd; y++)
{
double latitude = metadata.DataEndLat + (metadata.pixelSizeY * y);
// bounding box
if (y == yStart)
{
heightMap.BoundingBox.yMax = latitude;
heightMap.BoundingBox.xMin = metadata.DataStartLon + (metadata.pixelSizeX * xStart);
heightMap.BoundingBox.xMax = metadata.DataStartLon + (metadata.pixelSizeX * xEnd);
}
if (y == yEnd)
{
heightMap.BoundingBox.yMin = latitude;
}
for (int x = xStart; x <= xEnd; x++)
{
double longitude = metadata.DataStartLon + (metadata.pixelSizeX * x);
var tileX = (x / tileWidth) * tileWidth;
var tileY = (y / tileHeight) * tileHeight;
if (tilesCache == null)
{
tilesCache = new Dictionary <int, byte[]>();
}
var tileKey = (x / tileWidth) + (y / tileHeight) * (metadata.Width / tileWidth + 1);
if (!tilesCache.TryGetValue(tileKey, out buffer))
{
buffer = new byte[tileSize];
TiffFile.ReadTile(buffer, 0, tileX, tileY, 0, 0);
tilesCache.Add(tileKey, buffer);
}
var offset = x - tileX + (y - tileY) * tileHeight;
float heightValue = GetElevationAtPoint(metadata, offset, buffer);
if (heightValue <= 0)
{
heightMap.Minimum = Math.Min(heightMap.Minimum, heightValue);
heightMap.Maximum = Math.Max(heightMap.Maximum, heightValue);
}
else if (heightValue < 32768)
{
heightMap.Minimum = Math.Min(heightMap.Minimum, heightValue);
heightMap.Maximum = Math.Max(heightMap.Maximum, heightValue);
}
else
{
heightValue = (float)noDataValue;
}
coords.Add(new GeoPoint(latitude, longitude, heightValue));
}
}
}
else
{
// metadata.BitsPerSample
// When 16 we have 2 bytes per sample
// When 32 we have 4 bytes per sample
int bytesPerSample = metadata.BitsPerSample / 8;
byte[] byteScanline = new byte[metadata.ScanlineSize];
double endLat = metadata.DataEndLat + metadata.pixelSizeY / 2d;
double startLon = metadata.DataStartLon + metadata.pixelSizeX / 2d;
for (int y = yStart; y <= yEnd; y++)
{
TiffFile.ReadScanline(byteScanline, y);
// TODO: handle Cell registered DEMs: lat is 1/2 pixel off
double latitude = endLat + (metadata.pixelSizeY * y);
// bounding box
if (y == yStart)
{
heightMap.BoundingBox.yMax = latitude;
heightMap.BoundingBox.xMin = startLon + (metadata.pixelSizeX * xStart);
heightMap.BoundingBox.xMax = startLon + (metadata.pixelSizeX * xEnd);
}
else if (y == yEnd)
{
heightMap.BoundingBox.yMin = latitude;
}
for (int x = xStart; x <= xEnd; x++)
{
double longitude = startLon + (metadata.pixelSizeX * x);
float heightValue = 0;
switch (metadata.SampleFormat)
{
case RasterSampleFormat.FLOATING_POINT:
heightValue = BitConverter.ToSingle(byteScanline, x * bytesPerSample);
break;
case RasterSampleFormat.INTEGER:
heightValue = BitConverter.ToInt16(byteScanline, x * bytesPerSample);
break;
case RasterSampleFormat.UNSIGNED_INTEGER:
heightValue = BitConverter.ToUInt16(byteScanline, x * bytesPerSample);
break;
default:
throw new Exception("Sample format unsupported.");
}
if (heightValue <= 0)
{
heightMap.Minimum = Math.Min(heightMap.Minimum, heightValue);
heightMap.Maximum = Math.Max(heightMap.Maximum, heightValue);
}
else if (heightValue < 32768)
{
heightMap.Minimum = Math.Min(heightMap.Minimum, heightValue);
heightMap.Maximum = Math.Max(heightMap.Maximum, heightValue);
}
else
{
heightValue = (float)noDataValue;
}
coords.Add(new GeoPoint(latitude, longitude, heightValue));
}
}
}
heightMap.BoundingBox.zMin = heightMap.Minimum;
heightMap.BoundingBox.zMax = heightMap.Maximum;
Debug.Assert(heightMap.Width * heightMap.Height == coords.Count);
heightMap.Coordinates = coords;
return(heightMap);
}
