折线图中的点重叠存在问题

Question

我的绘图难以理解，因为我的观点是重叠的，我的线条有点宽。任何解决方案都将有所帮助。

我尝试使用alpha（），但不幸的是它没有用。

      ggplot(final, aes(wavelength, colour= Sites)) +  geom_line(aes(y = transmission, colour = Q)) +
          geom_point(aes(y = transmission, colour = Q, shape = Q, size = Q)) +
          geom_line(aes(y = transmission2, colour = L)) + geom_point(aes(y = transmission2, colour = L, shape = L, size = L)) + 
          geom_line(aes(y = transmission3, colour = O)) + geom_point(aes(y = transmission3, colour = O, shape = O, size = O)) +
          scale_size_manual("Sites", values=c(1,0.5,0.5)) +
          scale_shape_manual("Sites", values=c(17,25,23)) +
          scale_colour_manual("Sites", values=c("red","green","blue")) +
    scale_alpha_manual("Sites", values=c(3/8,3/8,3/8)) +
          theme_bw()
structure(list(wavelength = c(185, 186, 187, 188, 189, 190, 191, 
192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 
205, 206, 207, 208, 209, 210, 211, 212, 213, 214), transmission = c(0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0), transmission2 = c(0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0), transmission3 = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0), Q = c("Q", 
"Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", 
"Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", "Q", 
"Q", "Q", "Q"), L = c("L", "L", "L", "L", "L", "L", "L", "L", 
"L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", 
"L", "L", "L", "L", "L", "L", "L", "L", "L"), O = c("O", "O", 
"O", "O", "O", "O", "O", "O", "O", "O", "O", "O", "O", "O", "O", 
"O", "O", "O", "O", "O", "O", "O", "O", "O", "O", "O", "O", "O", 
"O", "O")), row.names = c(NA, 30L), class = "data.frame")