102 lines
2.2 KiB
Python
102 lines
2.2 KiB
Python
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#!/usr/bin/python3
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import sys
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from math import sin, cos, radians
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from shapely.geometry import LineString
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import matplotlib.pyplot as plt
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# bendri
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lambda_0 = 0
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dphi = 5
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dlambda = 5
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R = 6_388_945
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H = 350_000
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D = H + R
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# Įdomesni
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dphi = 2
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dlambda = 2
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phi_p, phi_s = 0, 32
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lambda_v, lambda_r = -16, 16
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plt.xkcd()
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# mano
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#phi_p, phi_s = 43, 53
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#lambda_v, lambda_r = -5, 5
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# Ovodo
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# phi_p, phi_s = 40, 50
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# lambda_v, lambda_r = -5, 5
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# apskaičiuoti
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nphi = int((phi_s-phi_p)/dphi)+1
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phi_0 = (phi_p+phi_s)/2
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nlambda = int((lambda_r-lambda_v)/dlambda)+1
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def c(x):
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return "{}°".format(x)
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def annotate(ax, text, point, heading):
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ax.annotate(text, point, textcoords="offset points", xytext=heading, fontsize='xx-small')
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def yx(phi, lambd):
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# phi - lat in degrees
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# lambd - lon in degrees
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rphi = radians(phi)
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rlambd = radians(lambd)
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cosz = sin(rphi)*sin(rphi_0)+cos(rphi)*cos(rphi_0)*cos(rlambd-rlambda_0)
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sinzcosa = sin(rphi)*cos(rphi_0)-cos(rphi)*sin(rphi_0)
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sinzsina = cos(rphi)*sin(rlambd-rlambda_0)
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x = H*R*sinzcosa/(D-R*cosz)
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y = H*R*sinzsina/(D-R*cosz)
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return (y/1e4, x/1e4)
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W, E, N, S = (-25, 0), (10, 0), (0, 10), (0, -25)
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# verčiame laipsnius į radianus
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for v in ['phi_0', 'phi_p', 'phi_s', 'lambda_0', 'lambda_v', 'lambda_r']:
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locals()["r"+v] = radians(locals()[v])
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points = []
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for i in range(nphi):
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phid = phi_p + i*dphi
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on_y = []
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for j in range(nlambda):
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lambdad = lambda_v + j*dlambda
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on_y.append(yx(phid, lambdad))
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points.append(sorted(on_y))
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fig, ax = plt.subplots()
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ax.axis("off")
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# abscises
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for i in range(nphi):
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row = [points[i][j] for j in range(nlambda)]
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ax.plot(*(LineString(row).xy), color="xkcd:black", linewidth=.5)
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annotate(ax, c(phi_p+i*dphi), row[0], W)
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annotate(ax, c(phi_p+i*dphi), row[-1], E)
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# ordinates
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for i in range(nlambda):
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col = [points[j][i] for j in range(nphi)]
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ax.plot(*(LineString(col).xy), color="xkcd:black", linewidth=.5)
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annotate(ax, c(lambda_v+i*dlambda), col[0], S)
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annotate(ax, c(lambda_v+i*dlambda), col[-1], N)
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if __name__ == '__main__':
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if len(sys.argv) == 2:
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plt.savefig(sys.argv[1], bbox_inches='tight')
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print("Saved %s" % sys.argv[1])
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else:
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plt.show()
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