/// <summary>
/// Parses the first 100 bytes of a shapefile into the important values
/// </summary>
/// <param name="inFilename">The filename to read</param>
public void Open(string inFilename)
{
_filename = inFilename;
// Position Field Value Type ByteOrder
// --------------------------------------------------------------
// Byte 0 File Code 9994 Integer Big
// Byte 4 Unused 0 Integer Big
// Byte 8 Unused 0 Integer Big
// Byte 12 Unused 0 Integer Big
// Byte 16 Unused 0 Integer Big
// Byte 20 Unused 0 Integer Big
// Byte 24 File Length File Length Integer Big
// Byte 28 Version 1000 Integer Little
// Byte 32 Shape Type Shape Type Integer Little
// Byte 36 Bounding Box Xmin Double Little
// Byte 44 Bounding Box Ymin Double Little
// Byte 52 Bounding Box Xmax Double Little
// Byte 60 Bounding Box Ymax Double Little
// Byte 68 Bounding Box Zmin Double Little
// Byte 76 Bounding Box Zmax Double Little
// Byte 84 Bounding Box Mmin Double Little
// Byte 92 Bounding Box Mmax Double Little
BufferedBinaryReader bbReader = new BufferedBinaryReader(inFilename);
bbReader.FillBuffer(100); // we only need to read 100 bytes from the header.
bbReader.Close(); // Close the internal readers connected to the file, but don't close the file itself.
// Reading BigEndian simply requires us to reverse the byte order.
_fileCode = bbReader.ReadInt32(false);
// Skip the next 20 bytes because they are unused
bbReader.Seek(20, System.IO.SeekOrigin.Current);
// Read the file length in reverse sequence
_fileLength = bbReader.ReadInt32(false);
// From this point on, all the header values are in little endian
// Read the version
_version = bbReader.ReadInt32();
// Read in the shapetype that should be the shapetype for the whole shapefile
_shapeType = (ShapeTypes)bbReader.ReadInt32();
// Get the extents, each of which are double values.
_xMin = bbReader.ReadDouble();
_yMin = bbReader.ReadDouble();
_xMax = bbReader.ReadDouble();
_yMax = bbReader.ReadDouble();
_zMin = bbReader.ReadDouble();
_zMax = bbReader.ReadDouble();
_mMin = bbReader.ReadDouble();
_mMax = bbReader.ReadDouble();
bbReader.Dispose();
}
/// <summary>
/// Obtains a typed list of ShapefilePoint structures with double values associated with the various coordinates.
/// </summary>
/// <param name="filename">A string filename</param>
/// <param name="progressHandler">A progress indicator</param>
private void FillPoints(string filename, IProgressHandler progressHandler)
{
// Check to ensure the filename is not null
if (filename == null)
{
throw new NullReferenceException(MessageStrings.ArgumentNull_S.Replace("%S",filename));
}
if (File.Exists(filename) == false)
{
throw new FileNotFoundException(MessageStrings.FileNotFound_S.Replace("%S", filename));
}
// Reading the headers gives us an easier way to track the number of shapes and their overall length etc.
List<ShapeHeader> shapeHeaders = ReadIndexFile(filename);
// Get the basic header information.
ShapefileHeader header = new ShapefileHeader(filename);
Extent = new Extent(new[] { header.Xmin, header.Ymin, header.Xmax, header.Ymax });
Envelope = Extent.ToEnvelope();
// Check to ensure that the filename is the correct shape type
if (header.ShapeType != ShapeTypes.Point && header.ShapeType != ShapeTypes.PointM && header.ShapeType != ShapeTypes.PointZ)
{
throw new ApplicationException(MessageStrings.FileNotPoints_S.Replace("%S", filename));
}
// This will set up a reader so that we can read values in huge chunks, which is much faster than one value at a time.
IO.BufferedBinaryReader bbReader = new IO.BufferedBinaryReader(filename, progressHandler);
if (bbReader.FileLength == 100)
{
bbReader.Close();
// the file is empty so we are done reading
return;
}
// Skip the shapefile header by skipping the first 100 bytes in the shapefile
bbReader.Seek(100, SeekOrigin.Begin);
int numShapes = shapeHeaders.Count;
byte[] bigEndian = new byte[numShapes * 8];
byte[] allCoords = new byte[numShapes * 16];
bool isM = false;
bool isZ = false;
if(header.ShapeType == ShapeTypes.PointM || header.ShapeType == ShapeTypes.PointZ)
{
isM = true;
}
if (header.ShapeType == ShapeTypes.PointZ)
{
isZ = true;
}
byte[] allM = new byte[8];
if(isM) allM = new byte[numShapes * 8];
byte[] allZ = new byte[8];
if(isZ) allZ = new byte[numShapes * 8];
for (int shp = 0; shp < numShapes; shp++)
{
// Read from the index file because some deleted records
// might still exist in the .shp file.
long offset = (shapeHeaders[shp].ByteOffset);
bbReader.Seek(offset, SeekOrigin.Begin);
bbReader.Read(bigEndian, shp * 8, 8);
ShapeTypes type = (ShapeTypes)bbReader.ReadInt32();
//bbReader.Seek(4, SeekOrigin.Current);
bbReader.Read(allCoords, shp * 16, 16);
if(isZ)
{
bbReader.Read(allZ, shp*8, 8);
}
if (isM)
{
bbReader.Read(allM, shp*8, 8);
}
ShapeRange shape = new ShapeRange(FeatureTypes.Point);
shape.StartIndex = shp;
shape.ContentLength = 8;
shape.NumPoints = 1;
shape.NumParts = 1;
ShapeIndices.Add(shape);
}
double[] vert = new double[2 * numShapes];
Buffer.BlockCopy(allCoords, 0, vert, 0, numShapes*16);
Vertex = vert;
if(isM)
{
double[] m = new double[numShapes];
Buffer.BlockCopy(allM, 0, m, 0, numShapes * 8);
M = m;
}
if(isZ)
{
double[] z = new double[numShapes];
Buffer.BlockCopy(allZ, 0, z, 0, numShapes * 8);
Z = z;
}
for (int shp = 0; shp < numShapes; shp++)
{
PartRange part = new PartRange(vert, shp, 0, FeatureTypes.Point);
part.NumVertices = 1;
ShapeRange shape = ShapeIndices[shp];
shape.Parts.Add(part);
shape.Extent = new Extent(new[] {vert[shp*2], vert[shp*2 + 1], vert[shp*2], vert[shp*2 + 1]});
}
bbReader.Dispose();
}
// X Y MultiPoints: Total Length = 28 Bytes
// ---------------------------------------------------------
// Position Value Type Number Byte Order
// ---------------------------------------------------------
// Byte 0 Record Number Integer 1 Big
// Byte 4 Content Length Integer 1 Big
// Byte 8 Shape Type 8 Integer 1 Little
// Byte 12 Xmin Double 1 Little
// Byte 20 Ymin Double 1 Little
// Byte 28 Xmax Double 1 Little
// Byte 36 Ymax Double 1 Little
// Byte 48 NumPoints Integer 1 Little
// Byte X Points Point NumPoints Little
// X Y M MultiPoints: Total Length = 34 Bytes
// ---------------------------------------------------------
// Position Value Type Number Byte Order
// ---------------------------------------------------------
// Byte 0 Record Number Integer 1 Big
// Byte 4 Content Length Integer 1 Big
// Byte 8 Shape Type 28 Integer 1 Little
// Byte 12 Box Double 4 Little
// Byte 44 NumPoints Integer 1 Little
// Byte X Points Point NumPoints Little
// Byte Y* Mmin Double 1 Little
// Byte Y + 8* Mmax Double 1 Little
// Byte Y + 16* Marray Double NumPoints Little
// X Y Z M MultiPoints: Total Length = 44 Bytes
// ---------------------------------------------------------
// Position Value Type Number Byte Order
// ---------------------------------------------------------
// Byte 0 Record Number Integer 1 Big
// Byte 4 Content Length Integer 1 Big
// Byte 8 Shape Type 18 Integer 1 Little
// Byte 12 Box Double 4 Little
// Byte 44 NumPoints Integer 1 Little
// Byte X Points Point NumPoints Little
// Byte Y Zmin Double 1 Little
// Byte Y + 8 Zmax Double 1 Little
// Byte Y + 16 Zarray Double NumPoints Little
// Byte Z* Mmin Double 1 Little
// Byte Z+8* Mmax Double 1 Little
// Byte Z+16* Marray Double NumPoints Little
private void FillPoints(string filename, IProgressHandler progressHandler)
{
// Check to ensure the filename is not null
if (filename == null)
{
throw new NullReferenceException(MessageStrings.ArgumentNull_S.Replace("%S", filename));
}
if (File.Exists(filename) == false)
{
throw new FileNotFoundException(MessageStrings.FileNotFound_S.Replace("%S", filename));
}
// Get the basic header information.
ShapefileHeader header = new ShapefileHeader(filename);
Extent = new Extent(new[] { header.Xmin, header.Ymin, header.Xmax, header.Ymax });
// Check to ensure that the filename is the correct shape type
if (header.ShapeType != ShapeTypes.MultiPoint &&
header.ShapeType != ShapeTypes.MultiPointM &&
header.ShapeType != ShapeTypes.MultiPointZ)
{
throw new ArgumentException(MessageStrings.FileNotLines_S.Replace("%S", filename));
}
// Reading the headers gives us an easier way to track the number of shapes and their overall length etc.
List<ShapeHeader> shapeHeaders = ReadIndexFile(filename);
// This will set up a reader so that we can read values in huge chunks, which is much faster than one value at a time.
IO.BufferedBinaryReader bbReader = new IO.BufferedBinaryReader(filename, progressHandler);
if (bbReader.FileLength == 100)
{
// The shapefile is empty so we can simply return here
bbReader.Close();
return;
}
// Skip the shapefile header by skipping the first 100 bytes in the shapefile
bbReader.Seek(100, SeekOrigin.Begin);
int numShapes = shapeHeaders.Count;
byte[] bigEndians = new byte[numShapes * 8];
byte[] allBounds = new byte[numShapes * 32];
ByteBlock allCoords = new ByteBlock(BLOCKSIZE);
bool isM = (header.ShapeType == ShapeTypes.MultiPointZ || header.ShapeType == ShapeTypes.MultiPointM);
bool isZ = (header.ShapeType == ShapeTypes.PolyLineZ);
ByteBlock allZ = null;
ByteBlock allM = null;
if (isZ)
{
allZ = new ByteBlock(BLOCKSIZE);
}
if (isM)
{
allM = new ByteBlock(BLOCKSIZE);
}
int pointOffset = 0;
for (int shp = 0; shp < numShapes; shp++)
{
// Read from the index file because some deleted records
// might still exist in the .shp file.
long offset = (shapeHeaders[shp].ByteOffset);
bbReader.Seek(offset, SeekOrigin.Begin);
// time: 200 ms
ShapeRange shape = new ShapeRange(FeatureTypes.MultiPoint);
shape.RecordNumber = bbReader.ReadInt32(false); // Byte 0 Record Number Integer 1 Big
shape.ContentLength = bbReader.ReadInt32(false); // Byte 4 Content Length Integer 1 Big
//bbReader.Read(bigEndians, shp * 8, 8);
shape.ShapeType = (ShapeTypes)bbReader.ReadInt32();
shape.StartIndex = pointOffset;
if (shape.ShapeType == ShapeTypes.NullShape)
{
continue;
}
bbReader.Read(allBounds, shp * 32, 32);
shape.NumParts = 1;
shape.NumPoints = bbReader.ReadInt32();
allCoords.Read(shape.NumPoints * 16, bbReader);
pointOffset += shape.NumPoints;
if (header.ShapeType == ShapeTypes.MultiPointM)
{
// These are listed as "optional" but there isn't a good indicator of how to determine if they were added.
// To handle the "optional" M values, check the contentLength for the feature.
// The content length does not include the 8-byte record header and is listed in 16-bit words.
if (shape.ContentLength * 2 > 44 + 4 * shape.NumParts + 16 * shape.NumPoints)
{
double mMin = bbReader.ReadDouble();
double mMax = bbReader.ReadDouble();
//bbReader.Seek(16, SeekOrigin.Current);
if (allM != null) allM.Read(shape.NumPoints * 8, bbReader);
}
}
if (header.ShapeType == ShapeTypes.MultiPointZ)
{
bool hasM = shape.ContentLength * 2 > 60 + 4 * shape.NumParts + 24 * shape.NumPoints;
double zMin = bbReader.ReadDouble();
double zMax = bbReader.ReadDouble();
// For Z shapefiles, the Z part is not optional.
if (allZ != null) allZ.Read(shape.NumPoints * 8, bbReader);
// These are listed as "optional" but there isn't a good indicator of how to determine if they were added.
// To handle the "optional" M values, check the contentLength for the feature.
// The content length does not include the 8-byte record header and is listed in 16-bit words.
if (hasM)
{
double mMin = bbReader.ReadDouble();
double mMax = bbReader.ReadDouble();
if (allM != null) allM.Read(shape.NumPoints * 8, bbReader);
}
}
// Now that we have read all the values, create the geometries from the points and parts arrays.
ShapeIndices.Add(shape);
}
double[] vert = allCoords.ToDoubleArray();
Vertex = vert;
if (isM) M = allM.ToDoubleArray();
if (isZ) Z = allZ.ToDoubleArray();
Array.Reverse(bigEndians);
List<ShapeRange> shapes = ShapeIndices;
double[] bounds = new double[numShapes * 4];
Buffer.BlockCopy(allBounds, 0, bounds, 0, allBounds.Length);
for (int shp = 0; shp < numShapes; shp++)
{
ShapeRange shape = shapes[shp];
shape.Extent = new Extent(bounds, shp * 4);
int endIndex = shape.NumPoints + shape.StartIndex;
int startIndex = shape.StartIndex;
int count = endIndex - startIndex;
PartRange partR = new PartRange(vert, shape.StartIndex, 0, FeatureTypes.MultiPoint);
partR.NumVertices = count;
shape.Parts.Add(partR);
}
GC.Collect();
bbReader.Dispose();
}