public GISLayer ReadShapefile(string shpfilename)
{
FileStream fsr = new FileStream(shpfilename, FileMode.Open); //打开shp文件
BinaryReader br = new BinaryReader(fsr); //获取文件流后用二进制读取工具
ShapefileHeader sfh = ReadFileHeader(br); //调用之前的函数 获取头文件
SHAPETYPE ShapeType = (SHAPETYPE)Enum.Parse( //类型整数变对应的枚举值
typeof(SHAPETYPE), sfh.ShapeType.ToString());
GISExtent extent = new GISExtent(sfh.Xmax, sfh.Xmin, sfh.Ymax, sfh.Ymin);
GISLayer layer = new GISLayer(shpfilename, ShapeType, extent); //gislayer的构造参数分别是名字 图层类型 范围
while (br.PeekChar() != -1)
{
RecordHeader rh = ReadRecordHeader(br);
int RecordLength = FromBigToLittle(rh.RecordLength) * 2 - 4;
byte[] RecordContent = br.ReadBytes(RecordLength);//将记录内容读入字节数组
if (ShapeType == SHAPETYPE.point)
{
GISPoint onepoint = ReadPoint(RecordContent);
GISFeature onefeature = new GISFeature(onepoint, new GISAttribute());
layer.AddFeature(onefeature);
}
}
br.Close();
fsr.Close(); //归还文件权限于操作系统
return(layer); //最后返回一个图层文件
}
public static GISLayer ReadShapefile(string shpfilename)
{
FileStream fsr = new FileStream(shpfilename, FileMode.Open); //打开shp文件
BinaryReader br = new BinaryReader(fsr); //获取文件流后用二进制读取工具
ShapefileHeader sfh = ReadFileHeader(br); //调用之前的函数 获取头文件
SHAPETYPE ShapeType = (SHAPETYPE)Enum.Parse( //类型整数变对应的枚举值
typeof(SHAPETYPE), sfh.ShapeType.ToString());
GISExtent extent = new GISExtent(sfh.Xmax, sfh.Xmin, sfh.Ymax, sfh.Ymin);
string dbffilename = shpfilename.Replace(".shp", ".dbf"); //更改后缀
DataTable table = ReadDBF(dbffilename);
GISLayer layer = new GISLayer(shpfilename, ShapeType, extent, ReadFields(table)); //gislayer的构造参数分别是名字 图层类型 范围 *GISField的泛型
int rowindex = 0; //当前读取的记录位置
while (br.PeekChar() != -1)
{
RecordHeader rh = ReadRecordHeader(br);
int RecordLength = FromBigToLittle(rh.RecordLength) * 2 - 4;
byte[] RecordContent = br.ReadBytes(RecordLength);//将记录内容读入字节数组
if (ShapeType == SHAPETYPE.point)
{
GISPoint onepoint = ReadPoint(RecordContent);
GISFeature onefeature = new GISFeature(onepoint, ReadAttribute(table, rowindex));
layer.AddFeature(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.AddFeature(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.AddFeature(onefeature);
}
}
rowindex++;
}
br.Close();
fsr.Close(); //归还文件权限于操作系统
return(layer); //最后返回一个图层文件
}
public SelectResult SelectPoint(GISVertex vertex, List <GISFeature> features,
GISView view, GISExtent MinSelectExtent)
{
Double distance = Double.MaxValue;
int id = -1;
for (int i = 0; i < features.Count; i++) //找最近的feature判断是否有效
{
if (MinSelectExtent.IntersectOrNot(features[i].spatialpart.extent) == false)
{
continue;
}
GISPoint point = (GISPoint)(features[i].spatialpart);
double dist = point.Distance(vertex);
if (dist < distance)//每次找到最小的距离并记录id号
{
distance = dist;
id = i;
}
}
Console.WriteLine("id:" + id.ToString()); //测试id是否存在
Console.WriteLine(features[id].spatialpart.centroid.x.ToString() + "|" + features[id].spatialpart.centroid.y.ToString());
Console.WriteLine("鼠标点到元素点在地图上相距" + distance.ToString()); //此处的distance是features中最近的元素点到鼠标点映射到地图上点的距离
//精选
if (id == -1) //经过遍历 没有与minsextent相交的点则跳出
{
SelectedFeature = null;
return(SelectResult.TooFar);
}
else
{
double screendistance = view.ToScreenDistance(vertex, features[id].spatialpart.centroid);
//Console.WriteLine(screendistance);
if (screendistance < GISConst.MinScreenDistance)
{
SelectedFeature = features[id];
return(SelectResult.OK);
}
else
{
SelectedFeature = null;
return(SelectResult.TooFar);//即使在粗选相交 精选距离也超过了限制 则返回
}
}
}
