/// <summary>
/// Reads and parses the geometry with ID 'oid' from the ShapeFile
/// </summary>
/// <remarks><see cref="FilterDelegate">Filtering</see> is not applied to this method</remarks>
/// <param name="oid">Object ID</param>
/// <returns>geometry</returns>
private unsafe IGeometry ReadGeometry(int oid)
{
if (_ShapeType == ShapeType.Polygon || _ShapeType == ShapeType.PolygonM || _ShapeType == ShapeType.PolygonZ)
{
return(ReadPolygon(oid));
}
var dataPtr = zeroPtr + recordHeaders[oid].Offset + 8;
var type = *((ShapeType *)dataPtr);
if (type == ShapeType.Null)
{
return(null);
}
dataPtr += 4;
if (IsPoint)
{
var x = *((double *)dataPtr); dataPtr += 8;
var y = *((double *)dataPtr);
return(GeometryFactory.CreatePoint(x, y));
}
if (_ShapeType == ShapeType.Multipoint || _ShapeType == ShapeType.MultiPointM || _ShapeType == ShapeType.MultiPointZ)
{
dataPtr += 32; // min/max box
var points = new List <IPoint>();
var nPoints = *(int *)dataPtr; // get the number of points
dataPtr += 4;
if (nPoints == 0)
{
return(null);
}
for (var i = 0; i < nPoints; i++)
{
var x = *((double *)dataPtr); dataPtr += 8;
var y = *((double *)dataPtr); dataPtr += 8;
points.Add(GeometryFactory.CreatePoint(x, y));
}
return(GeometryFactory.CreateMultiPoint(points.ToArray()));
}
if (_ShapeType == ShapeType.PolyLine || _ShapeType == ShapeType.Polygon ||
_ShapeType == ShapeType.PolyLineM || _ShapeType == ShapeType.PolygonM ||
_ShapeType == ShapeType.PolyLineZ || _ShapeType == ShapeType.PolygonZ)
{
dataPtr += 32; // min/max
int nParts = *(int *)dataPtr; // get number of parts (segments)
dataPtr += 4;
if (nParts == 0)
{
return(null);
}
int nPoints = *((int *)dataPtr); // get number of points
dataPtr += 4;
var segments = new int[nParts + 1];
//Read in the segment indexes
for (int b = 0; b < nParts; b++)
{
segments[b] = *((int *)dataPtr);
dataPtr += 4;
}
//add end point
segments[nParts] = nPoints;
if ((int)_ShapeType % 10 == 3)
{
var mline = new List <ILineString>();
for (var lineId = 0; lineId < nParts; lineId++)
{
var line = new List <Coordinate>();
for (var i = segments[lineId]; i < segments[lineId + 1]; i++)
{
var x = *((double *)dataPtr); dataPtr += 8;
var y = *((double *)dataPtr); dataPtr += 8;
line.Add(GeometryFactoryEx.CreateCoordinate(x, y));
}
//line.Vertices.Add(new SharpMap.Geometries.Point(
mline.Add(GeometryFactory.CreateLineString(line.ToArray()));
}
if (mline.Count == 1)
{
return(mline[0]);
}
return(GeometryFactory.CreateMultiLineString(mline.ToArray()));
}
// TODO: check it!
//(_ShapeType == ShapeType.Polygon etc...)
{
//First read all the rings
//List<SharpMap.Geometries.LinearRing> rings = new List<SharpMap.Geometries.LinearRing>();
var rings = new List <ILinearRing>();
for (int RingID = 0; RingID < nParts; RingID++)
{
//SharpMap.Geometries.LinearRing ring = new SharpMap.Geometries.LinearRing();
var ring = new List <Coordinate>();
for (int i = segments[RingID]; i < segments[RingID + 1]; i++)
{
ring.Add(GeometryFactoryEx.CreateCoordinate(brShapeFile.ReadDouble(), brShapeFile.ReadDouble()));
}
// polygon should be closed, try to fix
if (!ring[ring.Count - 1].Equals2D(ring[0]))
{
ring.Add(GeometryFactoryEx.CreateCoordinate(ring[0].X, ring[0].Y));
}
//ring.Vertices.Add(new SharpMap.Geometries.Point
rings.Add(GeometryFactory.CreateLinearRing(ring.ToArray()));
}
var IsCounterClockWise = new bool[rings.Count];
int PolygonCount = 0;
for (int i = 0; i < rings.Count; i++)
{
IsCounterClockWise[i] = GeometryFactory.IsCCW(rings[i].Coordinates);
if (!IsCounterClockWise[i])
{
PolygonCount++;
}
}
if (PolygonCount == 1) //We only have one polygon
{
ILinearRing shell = rings[0];
var holes = new List <ILinearRing>();
if (rings.Count > 1)
{
for (int i = 1; i < rings.Count; i++)
{
holes.Add(rings[i]);
}
}
return(GeometryFactory.CreatePolygon(shell, holes.ToArray()));
}
else
{
var polys = new List <IPolygon>();
ILinearRing shell = rings[0];
var holes = new List <ILinearRing>();
for (int i = 1; i < rings.Count; i++)
{
if (!IsCounterClockWise[i])
{
polys.Add(GeometryFactory.CreatePolygon(shell, null));
shell = rings[i];
}
else
{
holes.Add(rings[i]);
}
}
polys.Add(GeometryFactory.CreatePolygon(shell, holes.ToArray()));
return(GeometryFactory.CreateMultiPolygon(polys.ToArray()));
}
}
}
else
{
throw (new ApplicationException("Shapefile type " + _ShapeType.ToString() + " not supported"));
}
}