public GISFeature SelectPointByVertex(GISVertex vertex, double mindist)
{
Double distance = Double.MaxValue;
int id = -1;
for (int i = 0; i < Features.Count; i++)
{
if (Features[i].spatialpart.extent.WithInDistance(vertex, mindist) == false)
{
continue;
}
GISPoint point = (GISPoint)(Features[i].spatialpart);
double dist = point.Distance(vertex);
if (dist < distance)
{
distance = dist;
id = i;
}
}
return((distance < mindist) ? Features[id] : null);
}
public static GISLayer ReadShapeFile(string shpfilename)
{
FileStream fsr = new FileStream(shpfilename, FileMode.Open);
BinaryReader br = new BinaryReader(fsr);
ShapeFileHeader sfh = ReadFileHeader(br);
SHAPETYPE ShapeType = SHAPETYPE.POINT;
if (sfh.ShapeType == 1)
{
ShapeType = SHAPETYPE.POINT;
}
else if (sfh.ShapeType == 3)
{
ShapeType = SHAPETYPE.LINE;
}
else if (sfh.ShapeType == 5)
{
ShapeType = SHAPETYPE.POLYGON;
}
else
{
return(null);
}
GISExtent extent = new GISExtent(new GISVertex(sfh.Xmin, sfh.Ymin), new GISVertex(sfh.Xmax, sfh.Ymax));
string dbffilename = shpfilename.Replace(".shp", ".dbf");
DataTable table = ReadDBF(dbffilename);
GISLayer layer = new GISLayer(shpfilename, ShapeType, extent, ReadFields(table));
int rowindex = 0;
while (br.PeekChar() != -1)
{
RecordHeader rh = ReadRecordHeader(br);
int RecordLength = FromBigToLittle(rh.RecordLength);
byte[] RecordContent = br.ReadBytes(RecordLength * 2 - 4);
if (ShapeType == SHAPETYPE.POINT)
{
GISPoint onepoint = ReadPoint(RecordContent);
GISFeature onefeature = new GISFeature(onepoint, ReadAttribute(table, rowindex));
layer.Features.Add(onefeature);
}
if (ShapeType == SHAPETYPE.LINE)
{
List <GISLine> lines = ReadLines(RecordContent);
for (int i = 0; i < lines.Count; i++)
{
GISFeature onefeature = new GISFeature(lines[i], ReadAttribute(table, rowindex));
layer.Features.Add(onefeature);
}
}
if (ShapeType == SHAPETYPE.POLYGON)
{
List <GISPolygon> polygons = ReadPolygons(RecordContent);
for (int i = 0; i < polygons.Count; i++)
{
GISFeature onefeature = new GISFeature(polygons[i], ReadAttribute(table, rowindex));
layer.Features.Add(onefeature);
}
}
rowindex++;
//其它代码,用于处理RecordContent
}
br.Close();
fsr.Close();
return(layer);
}