基于python的CAD等高线绘制

这是我本科在做《路基工程课程设计》挡土墙设计的时候，老师只给了原始地面数据点，因为疫情在家时间充裕，我就摸索了python画CAD，最终实现了绘制不同等高距的等高线绘制。
python面向对象编程。

基础知识

我这个代码只适合地面趋势简单的，通过差值得到固定整数高程点，然后将相同高程点依次连接。

note：

  • 当时是在windows先写的代码，因为要用到win32com.client这个库，所以我估计 Mac下应该用不了，但可以修改代码绘制dxf文件，不调用CAD。
  • 后续我再补充 Excel文件、输出CAD的文件及效果图

源代码

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# _*_ coding:utf-8- _*_

from pyautocad import APoint, Autocad, aDouble
import win32com.client
import numpy as np

dgj = 0.5       # 等高距
ctfs = 10       # 放大倍数，本身采取m为单位绘制，可能放大10倍后输出效果好些

"""
等高线计算
"""
#连接excel读取数据，这个地方可以做一个前处理，直接把excel数据作为数组或者numpy数组进行处理

xlapp = win32com.client.Dispatch("Excel.Application")
wb = xlapp.ActiveWorkbook
ws = xlapp.ActiveWorkbook.ActiveSheet
"""
K58+70向右走为前进方向，绘制在
"""

"""
First
定义一个类，输入 list，其元素为APoint
内部函数得到插值的数据点，打印点数据
"""
class nei_cha:
    def __init__(self, pnts = [APoint(0,1)], dgj = 0.5, gu_ding_cha_zhi = "X" ):
        # gu_ding_cz = "X" 意思是不进行固定插值操作
        self.pnts = pnts
        self.dgj = dgj
        self.gu_ding_cha_zhi = gu_ding_cha_zhi

    # 输入两个三维坐标，x/y是相等的，内插得到所需高程
    # 返回的是，该区间内得到的点组成的list
    def do_two_points(self, p1 = APoint(0), p2 = APoint(0)):
        if self.gu_ding_cha_zhi == "X":
            nmax = int(max(p1.z, p2.z) // self.dgj)
            nmin = int(min(p1.z, p2.z) // self.dgj)
            if nmax == nmin:        # 这两个点之间内插不出来
                return 0
        else:
            nmax = self.gu_ding_cha_zhi
            nmin = self.gu_ding_cha_zhi - 1
            if (p1.z - nmax) * (p2.z - nmin) > 0:        # 固定插值不在区间内
                return 0

        if p1.x == p2.x:        # x坐标一样，需要内插Z到y
            """
            求直线方程，y
            """
            k = (p1.y - p2.y)/(p1.z - p2.z)
            b = p1.y - k * p1.z

            if self.gu_ding_cha_zhi == "X":
                ni = np.array(range(nmin, nmax)).reshape(int(nmax - nmin), 1)
                zi = (ni + 1) * self.dgj
            else:
                ni = np.array([self.gu_ding_cha_zhi]).reshape(int(nmax - nmin), 1)
                zi = ni
            yi = np.around(k * zi + b, 3)
            #yi = np.interp(zi, [p1.z, p2.z], [p1.y, p2.y])
            xi = np.full((len(yi), 1), p1.x)
            pts_np = np.hstack((xi, yi, zi))
            return  pts_np

        else:                   # y坐标一样，需要内插Z得到x
            return 0
    def do_it(self):
        pnts_np = np.array([])
        for i in range(len(self.pnts) - 1):

            p_np_i = self.do_two_points(self.pnts[i], self.pnts[i+1])
            if type(p_np_i) != type(0):
                try:
                    pnts_np = np.vstack((pnts_np, p_np_i))
                except:
                    pnts_np = p_np_i
        if len(pnts_np) != len(np.array([])):
            return pnts_np
        else:
            return 0



# points是原始地面点高程
ground_points = []
row = 2

while row <= 20:
    i = 6               # 左侧数据
    j = 8               # 右侧数据

    # 桩号点绘图坐标
    x0 = ((row - 2) / 3) * 10 + 70
    y0 = 0
    z0 = ws.cells(row, 7).value
    p0 = APoint(x0, y0, z0)
    pts = []
    pts.append(p0)


    #  拾取左侧点数据
    while i >= 1:
        try:
            z_ = ws.cells(row, i).value
            y_ = ws.cells(row + 1, i).value
            pti = pts[-1] + (0, y_, z_)
            pts.append(pti)
        except:
            pass
        i -= 1
    #  拾取右侧点数据
    while ws.cells(row, j).value:
        try:
            z_ = ws.cells(row, j).value
            y_ = - ws.cells(row + 1, j).value
            ptj = pts[0] + (0, y_, z_)
            pts.insert(0, ptj)
        except:
            print("右侧点拾取失败了：cells(%d,%d)"% (row, j))
            pass
        j += 1
    ground_points.append(pts)

    for i in pts:
        print(i)
    print("")
    row = row + 3

# 利用上方点开始使用类进行，插值
all_np = []
for i in ground_points:
    cha_zhi_la = nei_cha(i, dgj)
    a = cha_zhi_la.do_it()
    try:
        all_np = np.vstack((all_np, a))
    except:
        all_np = a
pts_all = [APoint(list(i)) for i in all_np]
pts_all.sort(key = lambda x:x.z)
del all_np

h_min = pts_all[0].z
h_max = pts_all[-1].z


zzzi = h_min
sorted_pts = []
while zzzi <= h_max:
    _ = [i for i in pts_all if i.z == zzzi]
    _.sort(key = lambda x:x[0])
    sorted_pts.append(_)
    zzzi += dgj
del pts_all
for i in sorted_pts:
    elevation = i[0].z
    print("高程为 %s 的数据点"% elevation)
    for l_ in i:
        print(l_)
# 连接cad，并输出结果

del sorted_pts[0:11]
del sorted_pts[-10:-1]
acad = Autocad(create_if_not_exists=True)
acad.prompt("connect with the Autocad successfully.")
print("connect with the Autocad successfully.")

dwg = acad.ActiveDocument

# 定义等高线图层
dgx = acad.doc.layers.add("等高线")
dgx.LineWeight = 25
dwg.ActiveLayer = dgx
dgxbz = acad.doc.layers.add("等高线标注")


for m in range(len(sorted_pts)):
    i = sorted_pts[m]
    elevation = i[0].z
    print("高程为 %s 的数据点"% elevation)
    for l_ in i:
        print(l_)
    try:


        for j in i:
            j.z = 0
        pt = aDouble([j for _ in i for j in _ * ctfs])
        hl = acad.model.AddPolyLine(pt)
        hl.LineWeight = 25
        hl.Elevation = elevation
        hl.Thickness = 900
        if m % 5 == 0:
            hl.LineWeight = 100
            hl.color = 1
            text_string = elevation
            insertpt = i[0] * ctfs
            textobj = acad.model.addMtext(insertpt, 26, text_string)
            textobj.Height = 8
            textobj.BackgroundFill = True
            textobj.color = 1
            textobj.layer = "等高线标注"

    except:
        print('*' * 10, "高程为 %s 的数据点不足，跳过绘制此等高线"% elevation)
        pass
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