using System;
using System.Collections;
using System.Collections.Generic;
using System.Data.OleDb;
using System.IO;
using System.Text;
namespace Catfood.Shapefile
{
/// <summary>
///
/// </summary>
public class ShpParser : IDisposable, IEnumerator<Shape>, IEnumerable<Shape>
{
private bool _disposed;
private bool _opened;
private int _currentIndex;
private int _count;
private RectangleD _boundingBox;
private ShapeType _type;
private int _currentPosition;
private FileStream _mainStream;
private Header _mainHeader;
/// <summary>
///
/// </summary>
public ShpParser()
{
_currentIndex = -1;
_currentPosition = 0;
}
/// <summary>
///
/// </summary>
/// <param name="path"></param>
public ShpParser(string path)
: this()
{
Open(path);
}
/// <summary>
///
/// </summary>
/// <param name="path"></param>
private void Open(string path)
{
if (_disposed)
{
throw new ObjectDisposedException("ShpParser");
}
if (string.IsNullOrEmpty(path))
{
throw new ArgumentNullException("path");
}
if (!File.Exists(path))
{
throw new FileNotFoundException("shp file not found", path);
}
_mainStream = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read);
if (_mainStream.Length < Header.HeaderLength)
{
throw new InvalidOperationException("Shapefile main file does not contain a valid header");
}
// read in and parse the headers
var headerBytes = new byte[Header.HeaderLength];
_mainStream.Read(headerBytes, 0, Header.HeaderLength);
_mainHeader = new Header(headerBytes);
_type = _mainHeader.ShapeType;
_boundingBox = new RectangleD(_mainHeader.XMin, _mainHeader.YMin, _mainHeader.XMax, _mainHeader.YMax);
_currentPosition = Header.HeaderLength;
_count = _mainHeader.FileLength * 2; // FileLength return the size of file in words (16 bytes)
_opened = true;
}
#region IDisposable Members
/// <summary>
/// Close the Shapefile. Equivalent to calling Dispose().
/// </summary>
public void Close()
{
Dispose();
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
private void Dispose(bool canDisposeManagedResources)
{
if (!_disposed)
{
if (canDisposeManagedResources)
{
if (_mainStream != null)
{
_mainStream.Close();
_mainStream = null;
}
}
_disposed = true;
_opened = false;
}
}
#endregion
public bool MoveNext()
{
if (_disposed) throw new ObjectDisposedException("ShpParser");
if (!_opened) throw new InvalidOperationException("ShpParser not open.");
if (_currentPosition < (_count - 1))
{
// try to read the next database record
return true;
}
else
{
// reached the last shape
return false;
}
}
public void Reset()
{
if (_disposed) throw new ObjectDisposedException("ShpParser");
if (!_opened) throw new InvalidOperationException("ShpParser not open.");
_currentIndex = -1;
}
public Shape Current
{
get
{
if (_disposed) throw new ObjectDisposedException("ShpParser");
if (!_opened) throw new InvalidOperationException("ShpParser not open.");
//get recordheader;
var recordheader = new byte[8];
_mainStream.Read(recordheader, 0, recordheader.Length);
int contentOffsetInWords = EndianBitConverter.ToInt32(recordheader, 0, ProvidedOrder.Big);
int contentLengthInWords = EndianBitConverter.ToInt32(recordheader, 4, ProvidedOrder.Big);
_mainStream.Seek(_currentPosition , SeekOrigin.Begin); // back to header of record
int bytesToRead = (contentLengthInWords * 2) + 8;
byte[] shapeData = new byte[bytesToRead];
_currentPosition += bytesToRead;
_mainStream.Read(shapeData, 0, bytesToRead);
return ShapeFactory.ParseShape(shapeData , null);
// return null;
}
}
object IEnumerator.Current
{
get
{
if (_disposed) throw new ObjectDisposedException("ShpParser");
if (!_opened) throw new InvalidOperationException("ShpParser not open.");
return this.Current;
}
}
public IEnumerator<Shape> GetEnumerator()
{
return (IEnumerator<Shape>)this;
}
IEnumerator IEnumerable.GetEnumerator()
{
return (System.Collections.IEnumerator)this;
}
}
}
如何使用ShpParser
using (var shapefile = new ShpParser("my.shp")
{
foreach (Shape shape in shapefile)
{
Console.WriteLine("ShapeType: {0}", shape.Type);
}
}
1 回答
好的,Shp文件是一个很好的设计文件,你可以看到描述here . shx和dbf只添加一些帮助来解析shp文件 . 我在Catfood.Shapefile中添加了一个类,它的名字是ShpParser . 此类的输入仅为Shp文件 . 它不需要shx和dbf文件来提取文件中的形状 .
如果元数据为null,则抛出两个类异常,请确保从以下方法中删除元数据异常:
1-形状构造函数2- ShapeFactory.ParseShape
这里是ShpParser的代码
}
如何使用ShpParser