R 缩放\填充\步骤中的单个选项可更改图例中的颜色渲染

我使用ggplot的scale\u fill\u stepsn生成一个具有阶梯比例的地图。当我使用选项n时，会在图例中正确渲染指定的颜色。n、 打断基于指定的打断数计算打断。但是，当我使用该选项手动指定与n.breaks中使用的打断数相同的打断时，图例中的颜色渲染会发生变化，并且不会正确渲染

这是没有道理的。第二个示例中的图例颜色是否与第一个示例中的图例颜色相同

library(urbnmapr)
library(ggplot2)
library(dplyr)
library(ggthemes)

# Set colors 
red   <- c(0.67, 0.75, 0.84, 0.92, 1,    1,    0.8, 0.53, 0,   0,    0,   0)
green <- c(0.25, 0.4,  0.56, 0.71, 0.86, 1,    1,   0.95, 0.9, 0.75, 0.6, 0.48)
blue  <- c(0.11, 0.18, 0.25, 0.33, 0.4,  0.45, 0.4, 0.27, 0,   0,    0,   0)

# Obtain county polygon data
states_sf <- get_urbn_map(map = "states", sf = TRUE)
counties_sf <- get_urbn_map(map = "counties", sf = TRUE)

# Assign random values of data to each count  
counties_sf$value = runif(length(counties_sf$county_fips), min=-3.0, max=3.0)

# Remove AK and HI - lower 48 only 
states_sf <- states_sf[!(states_sf$state_abbv %in% c("HI","AK")),]
counties_sf <- counties_sf[!(counties_sf$state_abbv %in% c("HI","AK")),]

# Plot county-level data with a discrete legend 

data_levels <- c(-3,-1.5, -0.8, -0.5, -0.25,-0.1,0.1,0.25,0.5,.8,1.5,3)
level_colors <- rgb(red, green, blue)

length(data_levels)
length(level_colors)


# First version - 
counties_sf %>%
  ggplot() +
  # Overlay State Outlines
  # Plot county data and fill with value
  geom_sf(mapping = aes(fill = value), color = NA) +
  geom_sf(data = states_sf, fill = NA, color = "black", size = 0.25) +
  # Remove grid lines from plot
  coord_sf(datum = NA) +
  #
  # THE FIRST OPTION of scale_fill_stepsn IS WHERE THEY ARE DIFFERENT 
  #
  scale_fill_stepsn(n.breaks=12, colors=level_colors, limits=c(-3,3), 
                    labels=scales::label_number(accuracy=0.1)) + 
  labs(title='This Data is Completely Random', 
       fill ='The Legend') + 
  theme_map() + 
  theme(legend.position = "bottom",
        legend.key.width=unit(1.5,"cm"),
        legend.box.background = element_rect(color="black", size=2),
        legend.title = element_text(face = "bold"),
        legend.spacing = unit(0.25,"cm"),
        legend.justification = "center",
        plot.title=element_text(hjust=0.5))  +
  guides(fill = guide_colorsteps(even.step=TRUE, 
                                 title.position="top", 
                                 title.hjust = 0.5,
                                 frame.colour = 'black', 
                                 barwidth=unit(250,'points'),
                                 axis.linewidth=unit(3,'points')))

此版本生成以下图像。请注意，图例中的颜色现在不同了。

---

第一个选项将-3到3之间的12个间隔均匀隔开，然后与您的颜色完全一致。而第二个选项设置间距不均的值，精确的颜色在某些中断之间。但是（隐藏的）渐变仍然是均匀分布的。要将渐变作为打断隔开，需要设置比例的

值

参数。下面是一个简化的例子

库（ggplot2）
非常好。非常感谢。
#  
# Second version - 
counties_sf %>%
  ggplot() +
  # Overlay State Outlines
  # Plot county data and fill with value
  geom_sf(mapping = aes(fill = value), color = NA) +
  geom_sf(data = states_sf, fill = NA, color = "black", size = 0.25) +
  # Remove grid lines from plot
  coord_sf(datum = NA) +
  #
  # THE FIRST OPTION of scale_fill_stepsn IS WHERE THEY ARE DIFFERENT
  # replaced n.breaks with breaks option
  #
  scale_fill_stepsn(breaks=data_levels, colors=level_colors, limits=c(-3,3), 
                    labels=scales::label_number(accuracy=0.1)) + 
  labs(title='This Data is Completely Random', 
       fill ='The Legend') + 
  theme_map() + 
  theme(legend.position = "bottom",
        legend.key.width=unit(1.5,"cm"),
        legend.box.background = element_rect(color="black", size=2),
        legend.title = element_text(face = "bold"),
        legend.spacing = unit(0.25,"cm"),
        legend.justification = "center",
        plot.title=element_text(hjust=0.5))  +
  guides(fill = guide_colorsteps(even.step=TRUE, 
                                 title.position="top", 
                                 title.hjust = 0.5,
                                 frame.colour = 'black', 
                                 barwidth=unit(250,'points'),
                                 axis.linewidth=unit(3,'points')))