我正在使用此代码绘制北美温度变化地图:
ggplot(maps, aes(y=Latitude, x=Longitude, z=variable)) +
ggtitle(title)+
scale_fill_brewer(palette = "Spectral")+
geom_contour_filled(breaks = c(-Inf,-2., -1.5, -1., -0.5, 0, 0.5, 1, 1.5, 2, 3, 4, 5, 7, 9, 11,Inf))+
xlim(-146,-44)+
ylim(35,90)+
theme(plot.title = element_text(hjust = 0.5))
我想更改调色板以获得更好的可视化效果。目前,它写着
scale_fill_brewer(palette = "Spectral")
,我要把它改成自定义调色板
colors <- c(rgb(10,40,100,max=255),rgb(51,102,217,max=255),rgb(105,138,236,max=255),rgb(151,180,250,max=255),rgb(204,217,255,max=255),rgb(255,245,204,max=255),rgb(255,224,153,max=255),rgb(255,203,102,max=255),rgb(255,180,51,max=255),rgb(255,140,51,max=255),rgb(255,85,0,max=255),rgb(230,40,30,max=255),rgb(191,0,0,max=255),rgb(140,0,0,max=255),rgb(108,0,0,max=255),rgb(110,0,70,max=255))
使用
scale_fill_brewer(palette = colors)
会报错,我也尝试过palette(colors)
,也是不行。
如何自定义参数可以识别的调色板?
如果我正确理解你的问题,你想创建一个自定义
scale_...
函数。简而言之,这是对源代码的深入研究。
我将展示一种方法,该方法只需修改包 RColorBrewer、scales,当然还有 ggplot2 中的现有函数。
RcolorBrewer::brewer.pal
,我想这基本上就是你想要的了。看到代码,它会根据您的“n”从颜色列表中选择正确的颜色。这就是您需要手动创建的。我刚刚复制了调色板“YlOrBr”中的颜色。需要考虑的事情:Brewer 调色板不是随机的,它们已经过测试和创建,可以识别打印、复印和色盲,所以我不确定创建自己的调色板是否非常聪明。查看 https://colorbrewer2.org/ 找到合适的调色板。 scales:::brewer_pal
scale_fill/scale_color
功能我已将功能归结为核心,因此它们不会进行通常的检查并且灵活性较差。您可以修改原始功能以恢复此功能。
library(ggplot2)
mybrewerpal <- function(n, name) {# modified RcolorBrewer::brewer.pal
## the first call to switch would not be necessary in this example,
## but I leave it in order to make the underlying structure in brewer.pal clearer
switch(name, mypal = switch(n - 2, rgb(c(255, 254, 217), c(247, 196, 95), c(188, 79, 14), maxColorValue = 255),
rgb(c(255, 254, 254, 204), c(255, 217, 153, 76), c(212, 142, 41, 2), maxColorValue = 255),
rgb(c(255, 254, 254, 217, 153), c(255, 217, 153, 95, 52), c(212, 142, 41, 14, 4), maxColorValue = 255),
rgb(c(255, 254, 254, 254, 217, 153), c(255, 227, 196, 153, 95, 52), c(212, 145, 79, 41, 14, 4), maxColorValue = 255),
rgb(c(255, 254, 254, 254, 236, 204, 140), c(255, 227, 196, 153, 112, 76, 45), c(212, 145, 79, 41, 20, 2, 4), maxColorValue = 255),
rgb(c(255, 255, 254, 254, 254, 236, 204, 140), c(255, 247, 227, 196, 153, 112, 76, 45), c(229, 188, 145, 79, 41, 20, 2, 4), maxColorValue = 255),
rgb(c(255, 255, 254, 254, 254, 236, 204, 153, 102), c(255, 247, 227, 196, 153, 112, 76, 52, 37), c(229, 188, 145, 79, 41, 20, 2, 4, 6), maxColorValue = 255)
))
}
brewer_pal2 <- # modified from scales:::brewer_pal
function() { # stripped down all arguments, just to show the core
function(n) {
mybrewerpal(n, "mypal") ##modified, usually this is selected by a function
## with type and name as arguments, selecting a palette from a list called scales:::brewer
}
}
scale_fill_custom <- ### modified from scale_fill_brewer, removed some arguments
function (..., aesthetics = "fill") {
discrete_scale(aesthetics, "custom", brewer_pal2(), ...) ## give a new name to the
## scale, it will create a new Scale object.
}
p <-
ggplot(mtcars, aes(x = mpg, y = disp)) +
scale_fill_custom()
p + geom_point(shape = 21, aes(fill = as.factor(cyl)))
p + geom_point(shape = 21, aes(fill = as.factor(carb)))
无需构建个人功能的其他解决方案是:
您可以直接在 ggplot 中调用
discrete_scale()
,并且要创建 n 颜色,您必须调用 grDevices::colorRampPalette(YOUR_COLORS)
。
set.seed(1)
tibble(score = round(runif(100,1,10))) %>%
count(score) %>%
ggplot(aes(x = score, y = n, fill = score %>% as.factor())) +
geom_col() +
scale_x_continuous(breaks = 1:10) +
scale_y_continuous(labels = scales::percent_format(scale = 1)) +
discrete_scale("fill", scale_name = "personal", palette = grDevices::colorRampPalette(c("#EE602D", "#FFCF26", "#01AEE6"))) +
theme_minimal() +
theme(legend.position = "none") +
labs(x = NULL, y = NULL)