/// <summary>
/// 内插值法求点的“地面高”
/// </summary>
/// <param name="pPnt"></param>
/// <returns>点的高程值</returns>
private double Calculate_Z2(IPoint pPnt)
{
double pZ = 0;
//================================================
double dRad = double.Parse("15".Trim()) / 2.0; //搜索半径一半
double dBufferRad = 0.0;
ITopologicalOperator pTopo = pPnt as ITopologicalOperator;
IGeometry pBuffer = pTopo.Buffer(dRad);
IPointCollection pPC = new MultipointClass();
pPC.AddPointCollection(PointCollectionFromEdit(pPnt, dRad));
pPC.AddPointCollection(pntColl(pBuffer));
//================================================
int pTag = 1;
//如果点数小于2,则增大搜索半径，重新搜索
while (pPC.PointCount < 2)
{
if (pTag > 4)//若重新搜索4次还没有点，则退出
{
break;
}
pTag++;
dBufferRad = dRad * pTag;
pBuffer = pTopo.Buffer(dBufferRad);
pPC.RemovePoints(0, pPC.PointCount);
pPC.AddPointCollection(PointCollectionFromEdit(pPnt, dBufferRad));
pPC.AddPointCollection(pntColl(pBuffer));
}
//================================================
if (pPC.PointCount > 1)
{
double pTolZ = 0;
double pLength = 0;
double iP = 0;
double pToliP = 0;//权系数
for (int i = 0; i < pPC.PointCount; i++)
{
IPoint pPt = pPC.get_Point(i);
if (pPt.Z >= 0 || pPt.Z < 0)
{
pLength = Get_Len_2piont(pPnt, pPt);
if (pLength > 0)
{
iP = 1 / Math.Pow(pLength, 2);
pToliP = pToliP + iP;
pTolZ = pTolZ + iP * pPt.Z;
}
}//if (pPt.Z != double.NaN)
}
if (pToliP != 0)
{
pZ = pTolZ / pToliP;
} //pToliP = 0使用初始化值0作为pZ结果
else //大于两个点均与查询点重合
{
pZ = 0;
}
}
else//点数小于两个
{
//if (frmSetValue.UseConst)
//{
// pZ = frmSetValue.ConstHight;
//}
//else
//{
// frmSetValue pFrmSetValue = new frmSetValue(pPnt.X, pPnt.Y);
// if (pFrmSetValue.ShowDialog() == DialogResult.OK)
// {
// pZ = pFrmSetValue.ReturnValue;
// bolEdit = true;
// }
//}
}
//================================================
return(pZ);
}