/// <summary>
/// 读取shx索引信息
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
private static List <ShxRecord> GetAllIndexRecords(Stream stream)
{
List <ShxRecord> records = new List <ShxRecord>();
try
{
stream.Position = 100;
byte[] streamBuffer;
do
{
streamBuffer = ShpUtil.ReadBytesFromStream(stream, 8);
if (streamBuffer.Length < 8)
{
break;
}
else
{
ShxRecord myRecord = new ShxRecord(streamBuffer);
records.Add(myRecord);
}
} while (streamBuffer.Length > 0);
}
catch
{
records.Clear();
}
return(records);
}
/// <summary>
/// 从shapefile生成FeatureSet
/// </summary>
/// <param name="shpFilePath"></param>
/// <returns></returns>
public static FeatureSet CreateFeatureSet(string shpFilePath)
{
if (!ShpUtil.VerificationShp(shpFilePath, out var subFiles))
{
throw new IOException("该shapefile文件不存在或者主文件缺失！");
}
//else
using var dbfReader = new DbfReader(subFiles.Item2);
var shxIndexs = new ShxReader().ReadShx(subFiles.Item1);
var recordNum = shxIndexs.Count;
using var shpReader = new ShpReader(shpFilePath, shxIndexs);
var fs = CreateFeatureSet(shpReader, dbfReader, recordNum);
if (File.Exists(subFiles.Item3))
{
string prjWkt = "";
using (var sr = new StreamReader(subFiles.Item3, Encoding.UTF8))
{
prjWkt = sr.ReadToEnd();
}
var proj = Crs.CreateFromWkt(prjWkt);
fs.Crs = proj;
}
return(fs);
}
public ShpReader(string shpFilePath)
{
string shxFilePath = shpFilePath.Substring(0, shpFilePath.Length - 3) + ".shx";
_shxRecords = new ShxReader().ReadShx(shxFilePath);
_readStream = new FileStream(shpFilePath, FileMode.Open, FileAccess.Read, FileShare.Read);
this.ShpHeader = ShpUtil.GetHeader(_readStream);
}
/// <summary>
/// 根据ShpReader和DbfReader创建FeatureSet
/// </summary>
/// <param name="shpReader"></param>
/// <param name="dbfReader"></param>
/// <param name="recordNum"></param>
/// <returns></returns>
private static FeatureSet CreateFeatureSet(ShpReader shpReader, DbfReader dbfReader, int recordNum)
{
GeometryType geometryType = (GeometryType)shpReader.ShpHeader.ShapeType;
var featureType = ShpUtil
.GeometryType2FeatureType(geometryType);
FeatureSet fs = new FeatureSet(featureType);
IFeatureList features = new FeatureList(fs);
for (int i = 0; i < recordNum; i++)
{
var spatialBytes = shpReader.GetNextRecord();
dbfReader.GetNextRow();
IGeometry geometry;
switch (geometryType)
{
case GeometryType.Point:
geometry = BytesToGeometry.CreatePoint(spatialBytes);
break;
case GeometryType.MultiPoint:
geometry = BytesToGeometry.CreateMultipoint(spatialBytes);
break;
case GeometryType.PolyLine:
geometry = BytesToGeometry.CreatePolyLine(spatialBytes);
break;
case GeometryType.Polygon:
geometry = BytesToGeometry.CreatePolygon(spatialBytes);
break;
default:
geometry = null;
break;
}
IFeature feature = new Feature(geometry);
features.Add(feature);
}
fs.Features.Set(features);
fs.AttrTable = dbfReader.DbfTable;
var header = shpReader.ShpHeader;
//fs.Envelope = new Envelope(header.XMin, header.YMin,
// header.XMax, header.YMax,
// header.ZMin, header.ZMax);
return(fs);
}
/// <summary>
/// 将FeatureSet保存为shapefile
/// </summary>
/// <param name="iFeatureSet"></param>
/// <param name="shpFilePath"></param>
public static void SaveFeatureSet(IFeatureSet iFeatureSet,
string shpFilePath)
{
var dir = Path.GetDirectoryName(shpFilePath);
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir ?? throw new InvalidOperationException(nameof(shpFilePath)));
}
ShpUtil.DeleteShp(shpFilePath);
var(shxFilePath, dbfFilePath, prjFilePath) = ShpUtil.GetSubFileName(shpFilePath);
using var dbfWriter = new DbfWriter(iFeatureSet.AttrTable,
dbfFilePath, DbfEncodingUtil.DefaultEncoding);
dbfWriter.Write();
var featureSet = (FeatureSet)iFeatureSet;
var header = featureSet.GetHeader();
using ShpWriter shpWriter = new ShpWriter(shpFilePath);
using ShxWriter shxWriter = new ShxWriter(shxFilePath);
shpWriter.WriterHeader(header);
shxWriter.WriterHeader(header);
int offset = 100;
foreach (var feature in featureSet.Features)
{
var contentByteLength = shpWriter.WriterRecord(feature);
shxWriter.WriterRecord(offset, contentByteLength);
offset += contentByteLength;
}
shpWriter.WriteFileLength();;
shxWriter.WriteFileLength();
if (featureSet.Crs != null)
{
using var fsStream = new FileStream(prjFilePath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.Read);
using var sw = new StreamWriter(fsStream);
sw.Write(featureSet.Crs.Wkt);
}
}
/// <summary>
/// 当前feature set对应的文件头
/// </summary>
/// <returns></returns>
internal byte[] GetHeader()
{
return(_header ??= ShpUtil.BuildHeader(this));
}
public ShpReader(Stream shpFileStream, List <ShxRecord> shxRecords)
{
_shxRecords = shxRecords;
_readStream = shpFileStream;
this.ShpHeader = ShpUtil.GetHeader(_readStream);
}
