//Indexing
public static async Task CreateIndex(string shpFileName)
{
ShxReader shxFile = new ShxReader(Shapefile.GetShxFileName(shpFileName));
var shapes = await ReadAsync(shpFileName);
int numberOfRecords = shxFile.NumberOfRecords;
List <Indexing.ShpIndex> indexes = new List <Indexing.ShpIndex>(numberOfRecords);
for (int i = 0; i < numberOfRecords; i++)
{
int offset, contentLength;
shxFile.GetRecord(i, out offset, out contentLength);
if (contentLength == 2)
{
continue;
}
indexes.Add(new Indexing.ShpIndex()
{
RecordNumber = i,
MinimumBoundingBox = shapes[indexes.Count].MinimumBoundingBox
});
}
Indexing.IndexIO.Write(GetIndexFileName(shpFileName), indexes);
}
private static IShapeCollection ExtractPolygons(System.IO.BinaryReader shpReader, ShxReader shxReader, List <Indexing.ShpIndex> indexes)
{
List <Polygon> geometries = new List <Polygon>(indexes.Count);
for (int i = 0; i < indexes.Count; i++)
{
int offset, contentLength;
shxReader.GetRecord(indexes[i].RecordNumber, out offset, out contentLength);
geometries[i] = PolygonReader.Read(shpReader, offset, contentLength);
}
return(new ShapeCollection <Polygon>(geometries));
}
private static IEsriShapeCollection ExtractPolyLines(System.IO.BinaryReader shpReader, ShxReader shxReader, List <Indexing.ShpIndex> indexes, int srid)
{
List <EsriPolyline> geometries = new List <EsriPolyline>(indexes.Count);
for (int i = 0; i < indexes.Count; i++)
{
int offset, contentLength;
shxReader.GetRecord(indexes[i].RecordNumber, out offset, out contentLength);
geometries[i] = PolyLineReader.Read(shpReader, offset, contentLength, srid);
}
return(new EsriShapeCollection <EsriPolyline>(geometries));
}