ggplot2：点和线的不同图例符号

Question

已经搜索了所有与此相关的线程，但找不到解决方案。

这是我的代码和附加的绘图结果：

g <-ggplot(NDVI2, aes(LAI2, NDVI, colour = Legend)) + 
    theme_bw (base_family = "Times") + 
    scale_colour_manual (values = c("purple", "green", "blue", "yellow",  "magenta","orange", "cyan", "red", "black")) + 
    geom_point (size = 3) +
    geom_smooth (aes(group = 1, colour = "Trendline"), method = "loess", size = 1, linetype = 5, se = FALSE) +
    geom_smooth (aes(group = 1, colour = "Regression (log)"),linetype = 1, size=1.2,method = "lm", formula = y~ log(x), se = FALSE) + 
    labs (title = "Correlation of LAI and NDVI")+ 
    theme (legend.title = element_text (size = 15)) 

这导致了这个情节：

如您所见，所有图例图标看起来都一样。我想要的是点显示为点，两条线（“回归”和“趋势线”）显示为线。

我尝试使用

guides (colour = guide_legend (override.aes = list(size = 1.5)))

但这又以同样的方式给了我所有图标，我不知道如何区分它们

我是 R 新手，这是我的第一个“复杂”情节。尝试通过在线帮助和谷歌找出大多数问题，但找不到解决此问题的方法。感谢大家的时间和帮助！

这是我的数据的dput：

dput(NDVI2)
structure(list(MeanRED = c(3.240264, 6.97950484, 3.75052276, 
4.62617908, 4.07743944, 4.88961572, 3.15865532, 2.28368236, 3.40793788, 
4.28833416, 4.52529496, 2.45698208, 3.84003364, 4.31006672, 3.29672264, 
4.21926652, 4.64357012, 3.94445908, 3.95942484, 1.22673756, 4.70933136, 
5.33718396, 5.71857348, 5.7014266, 3.85938572, 6.07816804, 2.93602476, 
5.00289296), MeanNIR = c(46.8226195806452, 48.4417953548387, 
47.8913064516129, 43.9416386774194, 44.7524788709677, 52.2142607741935, 
48.6422146774194, 44.6617992580645, 57.7213822580645, 58.5066447096774, 
56.6924350967742, 57.4100250967742, 58.0419292903226, 58.7054423225806, 
58.5283540645161, 54.7658463548387, 58.8950077096774, 58.2421209354839, 
57.8538210645161, 50.209727516129, 59.5780209354839, 60.1662100645161, 
62.1929408387097, 60.3309026451613, 57.859932516129, 63.5678422258065, 
55.2536370967742, 60.1808743548387), NDVI = c(0.870552242769623, 
0.748129155560663, 0.854748647859414, 0.809496111062421, 0.832994214160536, 
0.828746627367857, 0.878046244390978, 0.902709173224405, 0.888500710549276, 
0.863417928083076, 0.852157374806182, 0.917918660181389, 0.875891666709934, 
0.863206160341016, 0.893353221193523, 0.856937918252258, 0.853834622095331, 
0.873141147848366, 0.871890732089488, 0.952300860559358, 0.853491201866442, 
0.837040994913869, 0.831587513918106, 0.827314084928549, 0.874937512911774, 
0.825455384542418, 0.899087753174211, 0.846498808949291), LAI2 = c(1.1, 
1.2, 1.3, 1.4, 2.1, 2.2, 2.3, 2.4, 3.1, 3.2, 3.3, 3.4, 4.1, 4.2, 
4.3, 4.4, 5.1, 5.2, 5.3, 5.4, 6.1, 6.2, 6.3, 6.4, 7.1, 7.2, 7.3, 
7.4), Legend = c("LAI 1", "LAI 1", "LAI 1", "LAI 1", "LAI 2", 
"LAI 2", "LAI 2", "LAI 2", "LAI 3", "LAI 3", "LAI 3", "LAI 3", 
"LAI 4", "LAI 4", "LAI 4", "LAI 4", "LAI 5", "LAI 5", "LAI 5", 
"LAI 5", "LAI 6", "LAI 6", "LAI 6", "LAI 6", "LAI 7", "LAI 7", 
"LAI 7", "LAI 7")), .Names = c("MeanRED", "MeanNIR", "NDVI", 
"LAI2", "Legend"), class = "data.frame", row.names = c("LAI 1-1", 
"LAI 1-2", "LAI 1-3", "LAI 1-4", "LAI 2-1", "LAI 2-2", "LAI 2-3", 
"LAI 2-4", "LAI 3-1", "LAI 3-2", "LAI 3-3", "LAI 3-4", "LAI 4-1", 
"LAI 4-2", "LAI 4-3", "LAI 4-4", "LAI 5-1", "LAI 5-2", "LAI 5-3", 
"LAI 5-4", "LAI 6-1", "LAI 6-2", "LAI 6-3", "LAI 6-4", "LAI 7-1", 
"LAI 7-2", "LAI 7-3", "LAI 7-4"))

Answer 1

override.aes 绝对是自定义图例的良好开端。在您的情况下，您可以删除图例中不需要的shape，方法是将它们设置为NA，并将不需要的linetype 设置为blank：

ggplot(data = NDVI2, aes(x = LAI2, y = NDVI, colour = Legend)) + 
  geom_point(size = 3) +
  geom_smooth(aes(group = 1, colour = "Trendline"),
               method = "loess", se = FALSE, linetype = "dashed") +
  geom_smooth(aes(group = 1, colour = "Regression (log)"),
               method = "lm", formula = y ~ log(x), se = FALSE, linetype = "solid") +
  scale_colour_manual(values = c("purple", "green", "blue", "yellow", "magenta","orange", "cyan", "red", "black"),
                       guide = guide_legend(override.aes = list(
                         linetype = c(rep("blank", 7), "solid", "dashed"),
                         shape = c(rep(16, 7), NA, NA))))