/// <summary>
/// Read GeoTiff data info
/// </summary>
/// <param name="aFile">file path</param>
public override void ReadDataInfo(string aFile)
{
this.FileName = aFile;
FileStream sr = new FileStream(aFile, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(sr);
//Image file header (IFH)
_byteOrder = ASCIIEncoding.ASCII.GetString(br.ReadBytes(2));
int version = BitConverter.ToUInt16(br.ReadBytes(2), 0);
long offset = BitConverter.ToUInt32(br.ReadBytes(4), 0);
//Read IFDs
ReadIFD(br, offset);
br.Close();
sr.Close();
IFDEntry widthIFD = this.FindTag(Tag.ImageWidth);
IFDEntry heightIFD = this.FindTag(Tag.ImageLength);
int width = (int)widthIFD.ValueOffset;
int height = (int)heightIFD.ValueOffset;
double[] X = new double[width];
double[] Y = new double[height];
IFDEntry modelTiePointTag = FindTag(Tag.ModelTiepointTag);
IFDEntry modelPixelScaleTag = FindTag(Tag.ModelPixelScaleTag);
double minLon = modelTiePointTag.ValueD[3];
double maxLat = modelTiePointTag.ValueD[4];
double xdelt = modelPixelScaleTag.ValueD[0];
double ydelt = modelPixelScaleTag.ValueD[1];
for (int i = 0; i < width; i++)
{
X[i] = minLon + xdelt * i;
}
for (int i = 0; i < height; i++)
{
Y[height - i - 1] = maxLat - ydelt * i;
}
Dimension xdim = new Dimension(DimensionType.X);
xdim.SetValues(X);
Dimension ydim = new Dimension(DimensionType.Y);
ydim.SetValues(Y);
Variable var = new Variable();
var.Name = "var";
var.SetDimension(ydim);
var.SetDimension(xdim);
List <Variable> vars = new List <Variable>();
vars.Add(var);
this.Variables = vars;
}
private int readIntValue(BinaryReader br, IFDEntry ifd)
{
switch (ifd.Type.Code)
{
case 1:
case 2:
return(br.ReadByte());
case 3:
return(br.ReadUInt16());
case 4:
case 5:
return(br.ReadInt32());
}
return(0);
}
private void readValues(BinaryReader br, IFDEntry ifd)
{
if (ifd.Type == FieldType.ASCII)
{
ifd.ValueS = readSValue(br, ifd);
}
else if (ifd.Type == FieldType.RATIONAL)
{
ifd.Value = new int[ifd.Length * 2];
for (int i = 0; i < ifd.Length * 2; i++)
{
ifd.Value[i] = readIntValue(br, ifd);
}
}
else if (ifd.Type == FieldType.FLOAT)
{
ifd.ValueD = new double[ifd.Length];
for (int i = 0; i < ifd.Length; i++)
{
ifd.ValueD[i] = br.ReadSingle();
}
}
else if (ifd.Type == FieldType.DOUBLE)
{
ifd.ValueD = new double[ifd.Length];
for (int i = 0; i < ifd.Length; i++)
{
ifd.ValueD[i] = br.ReadDouble();
}
}
else
{
ifd.Value = new int[ifd.Length];
for (int i = 0; i < ifd.Length; i++)
{
ifd.Value[i] = readIntValue(br, ifd);
}
}
}
private double[] ReadData(BinaryReader br, int width, int height)
{
double[] values = new double[width * height];
IFDEntry tileOffsetTag = FindTag(Tag.TileOffsets);
if (tileOffsetTag != null)
{
int tileOffset = tileOffsetTag.Value[0];
IFDEntry tileSizeTag = FindTag(Tag.TileByteCounts);
int tileSize = tileSizeTag.Value[0];
}
else
{
IFDEntry stripOffsetTag = FindTag(Tag.StripOffsets);
if (stripOffsetTag != null)
{
int stripNum = stripOffsetTag.Length;
int stripOffset;
IFDEntry stripSizeTag = FindTag(Tag.StripByteCounts);
int stripSize = stripSizeTag.Value[0];
IFDEntry rowsPerStripTag = FindTag(Tag.RowsPerStrip);
int rowNum = rowsPerStripTag.Value[0];
int n = 0;
for (int i = 0; i < stripNum; i++)
{
stripOffset = stripOffsetTag.Value[i];
br.BaseStream.Seek(stripOffset, SeekOrigin.Begin);
for (int j = 0; j < width * rowNum; j++)
{
values[n] = br.ReadUInt16();
n += 1;
}
}
}
}
return(values);
}
private String readSValue(BinaryReader br, IFDEntry ifd)
{
byte[] dst = br.ReadBytes(ifd.Length);
return(ASCIIEncoding.ASCII.GetString(dst));
}
private void ReadIFD(BinaryReader br, long offset)
{
br.BaseStream.Seek(offset, SeekOrigin.Begin);
int tagNum = BitConverter.ToUInt16(br.ReadBytes(2), 0);
_tags = new List <IFDEntry>();
int i;
bool isGeoTiff = false;
IFDEntry geoTiffTag = new IFDEntry();
long position;
for (i = 0; i < tagNum; i++)
{
IFDEntry aIFD = new IFDEntry();
aIFD.Tag = new Tag(BitConverter.ToUInt16(br.ReadBytes(2), 0));
aIFD.Type = FieldType.Get(BitConverter.ToUInt16(br.ReadBytes(2), 0));
aIFD.Length = BitConverter.ToInt32(br.ReadBytes(4), 0);
byte[] bytes = br.ReadBytes(4);
aIFD.ValueOffset = BitConverter.ToUInt32(bytes, 0);
position = br.BaseStream.Position;
if (aIFD.Length * aIFD.Type.Size <= 4)
{
br.BaseStream.Seek(-4, SeekOrigin.Current);
readValues(br, aIFD);
}
else
{
br.BaseStream.Seek(aIFD.ValueOffset, SeekOrigin.Begin);
readValues(br, aIFD);
}
br.BaseStream.Position = position;
_tags.Add(aIFD);
if (!isGeoTiff)
{
if (aIFD.Tag.Code == 34735)
{
isGeoTiff = true;
geoTiffTag = aIFD;
}
}
}
offset = BitConverter.ToUInt16(br.ReadBytes(2), 0);
if (isGeoTiff)
{
offset = geoTiffTag.ValueOffset;
br.BaseStream.Seek(offset, SeekOrigin.Begin);
GeoHeader geoHeader = new GeoHeader();
geoHeader.KeyDirectoryVersion = BitConverter.ToUInt16(br.ReadBytes(2), 0);
geoHeader.KeyRevision = BitConverter.ToUInt16(br.ReadBytes(2), 0);
geoHeader.MinorRevision = BitConverter.ToUInt16(br.ReadBytes(2), 0);
geoHeader.NumberOfKeys = BitConverter.ToUInt16(br.ReadBytes(2), 0);
List <KeyEntry> keyEntries = new List <KeyEntry>();
for (i = 0; i < geoHeader.NumberOfKeys; i++)
{
KeyEntry keyEntry = new KeyEntry();
keyEntry.KeyID = BitConverter.ToUInt16(br.ReadBytes(2), 0);
keyEntry.TIFFTagLocation = BitConverter.ToUInt16(br.ReadBytes(2), 0);
keyEntry.Count = BitConverter.ToUInt16(br.ReadBytes(2), 0);
keyEntry.Value_Offset = BitConverter.ToUInt16(br.ReadBytes(2), 0);
keyEntries.Add(keyEntry);
}
}
}
