175 lines
6.4 KiB
Python
175 lines
6.4 KiB
Python
import math
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import ezdxf
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from osgeo import gdal
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import numpy as np
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class Dem:
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def __init__(self, filepath):
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self._dataset = gdal.Open(filepath)
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def get_dem_info(self, if_print=False):
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"""Get the information of DEM data.
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Parameters:
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dem_data <osgeo.gdal.Dataset> -- The data of DEM.
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if_print <bool> -- If print the information of DEM. Default is False (not print).
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Return:
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... <...> -- The information and parameters of DEM.
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"""
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dem_data = self._dataset
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dem_row = dem_data.RasterYSize # height
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dem_col = dem_data.RasterXSize # width
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dem_band = dem_data.RasterCount
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dem_gt = dem_data.GetGeoTransform()
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dem_proj = dem_data.GetProjection()
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if if_print:
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print("\nThe information of DEM:")
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print("The number of row (height) is: %d" % dem_row)
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print("The number of column (width) is: %d" % dem_col)
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print("The number of band is: %d" % dem_band)
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print("The 6 GeoTransform parameters are:\n", dem_gt)
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print("The GCS/PCS information is:\n", dem_proj)
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return dem_row, dem_col, dem_band, dem_gt, dem_proj
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def get_elevation(self, site_latlng):
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"""Get the elevation of given locations from DEM in GCS.
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Parameters:
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dem_gcs <osgeo.gdal.Dataset> -- The input DEM (in GCS).
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site_latlng <numpy.ndarray> -- The latitude and longitude of given locations.
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Return:
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site_ele <numpy.ndarray> -- The elevation and other information of given locations.
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"""
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gdal_data = self._dataset
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# gdal_band = gdal_data.GetRasterBand(1)
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# nodataval = gdal_band.GetNoDataValue()
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# if np.any(gdal_array == nodataval):
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# gdal_array[gdal_array == nodataval] = np.nan
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gt = gdal_data.GetGeoTransform()
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# print("\nThe 6 GeoTransform parameters of DEM are:\n", gt)
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N_site = site_latlng.shape[0]
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Xgeo = site_latlng[:, 0]
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Ygeo = site_latlng[:, 1]
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site_ele = np.zeros(N_site)
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for i in range(N_site):
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# Note:
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# Xgeo = gt[0] + Xpixel * gt[1] + Yline * gt[2]
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# Ygeo = gt[3] + Xpixel * gt[4] + Yline * gt[5]
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#
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# Xpixel - Pixel/column of DEM
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# Yline - Line/row of DEM
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#
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# Xgeo - Longitude
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# Ygeo - Latitude
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#
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# [0] = Longitude of left-top pixel
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# [3] = Latitude of left-top pixel
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#
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# [1] = + Pixel width
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# [5] = - Pixel height
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#
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# [2] = 0 for north up DEM
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# [4] = 0 for north up DEM
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Xpixel = (Xgeo[i] - gt[0]) / gt[1]
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Yline = (Ygeo[i] - gt[3]) / gt[5]
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# 寻找左上，左下，右上，右下4个点
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lu_xy = np.array([math.floor(Xpixel), math.floor(Yline)]) # 左上
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ld_xy = np.array([math.floor(Xpixel), math.ceil(Yline)]) # 左下
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ru_xy = np.array([math.ceil(Xpixel), math.floor(Yline)]) # 右上
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rd_xy = np.array([math.ceil(Xpixel), math.ceil(Yline)]) # 右下
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lu_elevation = gdal_data.ReadAsArray(
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int(lu_xy[0]), int(lu_xy[1]), 1, 1
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).astype(float)
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ld_elevation = gdal_data.ReadAsArray(
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int(ld_xy[0]), int(ld_xy[1]), 1, 1
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).astype(float)
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ru_elevation = gdal_data.ReadAsArray(
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int(ru_xy[0]), int(ru_xy[1]), 1, 1
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).astype(float)
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rd_elevation = gdal_data.ReadAsArray(
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int(rd_xy[0]), int(rd_xy[1]), 1, 1
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).astype(float)
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# delta_x = (Xpixel - ld_xy[0]) / 1 # 距离是1
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# delta_y = (ld_xy[1]-Yline) / 1
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# site_ele[i] = (
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# ld_elevation
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# + (lu_elevation - ld_elevation) * delta_y
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# + (rd_elevation - ld_elevation) * delta_x
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# + (ld_elevation - lu_elevation + ru_elevation - rd_elevation)
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# * delta_x
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# * delta_y
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# )
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# 通过空间平面方程乃拟合Z值
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equa_a = np.array(
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[
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[lu_xy[0], lu_xy[0] * lu_xy[1], lu_xy[1], 1],
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[ld_xy[0], ld_xy[0] * ld_xy[1], ld_xy[1], 1],
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[ru_xy[0], ru_xy[0] * ru_xy[1], ru_xy[1], 1],
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[rd_xy[0], rd_xy[0] * rd_xy[1], rd_xy[1], 1],
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]
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)
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equa_b = np.array(
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[lu_elevation[0], ld_elevation[0], ru_elevation[0], rd_elevation[0]]
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)
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equa_c = np.linalg.solve(equa_a, equa_b)
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point_z = (
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Xpixel * equa_c[0]
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+ equa_c[1] * Xpixel * Yline
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+ equa_c[2] * Yline
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+ equa_c[3]
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)
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site_ele[i] = point_z
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print(f"row:{Yline} col:{Xpixel} elev:{site_ele[i]}")
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return site_ele
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def to_line_coordination(point_x_s, point_y_s, point_x_e, point_y_e):
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path_length = ((point_x_s - point_x_e) ** 2 + (point_y_s - point_y_e) ** 2) ** 0.5
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n = round(path_length / 1)
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point_x = np.linspace(point_x_s, point_x_e, n, endpoint=True)
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point_y = np.linspace(point_y_s, point_y_e, n, endpoint=True)
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r = np.array([point_x, point_y]).transpose()
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return r
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def distance(a, b):
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r = np.sum((a - b) ** 2) ** 0.5
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return r
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if __name__ == "__main__":
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dem = Dem(r"e:\西北院\天都山750kV线路\天都山-妙岭卫片\ASC\tianmiaoN03-dem.tif")
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dem.get_dem_info(if_print=True)
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line_coordination = to_line_coordination(
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573284.886, 4104898.933, 574543.845, 4105825.047
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)
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elevation = dem.get_elevation(line_coordination)
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# fdsfd = np.array([
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# [573284.886, 4104898.933],
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# [573286.584, 4104900.182],
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# [573288.281, 4104901.431],
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# [573289.979 , 4104902.68],
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# [573291.677 , 4104903.929],
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# [573293.374 , 4104905.178],
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#
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# ])
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# elevation = dem.get_elevation(elevation)
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doc = ezdxf.new(dxfversion="R2010")
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msp = doc.modelspace()
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x_axis = [0]
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cord_0 = line_coordination[0, :]
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for cord in line_coordination[1:]:
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x_axis.append(distance(cord, cord_0))
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msp.add_polyline2d(
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[(x_axis[i] / 5, elevation[i] * 2) for i in range(len(elevation))]
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)
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doc.saveas("d.dxf")
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print("Finished.")
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