与ggplot的调色板

时间:2015-07-22 10:46:43

标签: r plot ggplot2

为了生成可复制的示例,我将不得不提交shapefile数据等,这对您来说很麻烦(下载数据等),所以这里只是提供最后一部分,而不是{{1} }

以下是示例代码:

ggplot

基本上,我试图通过定义颜色范围来应用我自己的颜色来填充区域。上述方法不起作用,因为它会产生错误:

cols <- colorRampPalette(c("darkgreen","yellow","red"), space = "rgb")
myPal <- cols(11) 

ggplot(data=df, aes(x=long, y=lat, group=group)) + 
   geom_polygon(aes(fill = measure))+    # draw polygons
   coord_equal() +
   scale_x_continuous(breaks = as.numeric(levels(factor(df$measure))))+
   scale_fill_manual(values = myPal)+
   labs(title="mesure level", x="", y="")+
   theme(axis.text=element_blank(),axis.ticks=element_blank())

编辑:但是这有效:

Error: Continuous value supplied to discrete scale

EDIT2:ggplot(data=df, aes(x=long, y=lat, group=group)) + geom_polygon(aes(fill = measure))+ # draw polygons coord_equal() + geom_path(color="grey", linestyle=2)+ scale_fill_gradient(low = "#ffffcc", high = "#ff4444", space = "Lab", na.value = "grey50", guide = "colourbar")+ labs(title="measure level", x="", y="")+ theme(axis.text=element_blank(),axis.ticks=element_blank()) 变量是数字(),这是我插入度量的方式:

measure

df$measure <- as.numeric(round(runif(nrow(df), 0, 1), 1)) 很大,所以这里是str()

dput

2 个答案:

答案 0 :(得分:6)

是的。 scale_fill_gradient是连续的。 scale_fill_manual是离散的,measure肯定是数字(而不是因素),所以你看到的是完全预期的行为。这是一个帮助解释的玩具示例:

library(rgdal)
library(curl)
library(ggplot2)
library(ggthemes)

# get a simple shapefile

map_url <- "https://andrew.cartodb.com/api/v2/sql?filename=us_states_hexgrid&q=SELECT+*+FROM+andrew.us_states_hexgrid&format=geojson&api_key="

res <- curl_fetch_disk(map_url, "hexes.json")

hex <- readOGR("hexes.json", "OGRGeoJSON")

## OGR data source with driver: GeoJSON 
## Source: "hexes.json", layer: "OGRGeoJSON"
## with 51 features
## It has 6 fields

str(hex@data)

## 'data.frame':    51 obs. of  6 variables:
##  $ cartodb_id: int  1219 1217 1218 220 215 228 232 227 230 229 ...
##  $ created_at: Factor w/ 4 levels "2015-05-13T22:02:22Z",..: 4 2 3 1 1 1 1 1 1 1 ...
##  $ updated_at: Factor w/ 51 levels "2015-05-14T14:17:56Z",..: 20 40 47 12 44 2 3 11 19 25 ...
##  $ label     : Factor w/ 51 levels "A.K.","Ala.",..: 20 40 47 12 44 2 3 11 19 25 ...
##  $ bees      : num  60.5 47.8 33.9 13.9 46.3 48.1 42.9 34.9 44.3 38.7 ...
##  $ iso3166_2 : Factor w/ 51 levels "AK","AL","AR",..: 22 40 47 12 44 2 4 11 19 26 ...

我们将使用bees,因为它与您的measure类似。

# make it so we can use the polygons in ggplot

hex_map <- fortify(hex, region="iso3166_2")

str(hex_map)

## 'data.frame':    357 obs. of  7 variables:
##  $ long : num  -133 -130 -130 -133 -135 ...
##  $ lat  : num  55.3 54.4 52.5 51.6 52.5 ...
##  $ order: int  1 2 3 4 5 6 7 8 9 10 ...
##  $ hole : logi  FALSE FALSE FALSE FALSE FALSE FALSE ...
##  $ piece: Factor w/ 1 level "1": 1 1 1 1 1 1 1 1 1 1 ...
##  $ group: Factor w/ 51 levels "AK.1","AL.1",..: 1 1 1 1 1 1 1 2 2 2 ...
##  $ id   : chr  "AK" "AK" "AK" "AK" ...

默认情况下,bees将被视为连续变量,默认填充色标将反映出:

gg <- ggplot()
gg <- gg + geom_map(data=hex_map, map=hex_map,
                    aes(x=long, y=lat, map_id=id),
                    fill="#ffffff", color="#7f7f7f", size=0.25)
gg <- gg + geom_map(data=hex@data, map=hex_map, aes(map_id=iso3166_2, fill=bees))
gg <- gg + coord_map()
gg <- gg + theme_map()
gg <- gg + theme(legend.position="right")
gg

enter image description here

你可以让ggplot使用自动剪切&amp;离散色图与带scale_fill_distiller的连续色图:

gg <- ggplot()
gg <- gg + geom_map(data=hex_map, map=hex_map,
                    aes(x=long, y=lat, map_id=id),
                    fill="#ffffff", color="#7f7f7f", size=0.25)
gg <- gg + geom_map(data=hex@data, map=hex_map, aes(map_id=iso3166_2, fill=bees))
gg <- gg + scale_fill_distiller()
gg <- gg + coord_map()
gg <- gg + theme_map()
gg <- gg + theme(legend.position="right")
gg

enter image description here

您还可以在ggplot操作之外进行手动剪切,并将该新列传递到scale_fill_manual

如果必须使用连续色标,考虑使用viridis色彩映射:

devtools::install_github("sjmgarnier/viridis")
library(viridis)

gg <- ggplot()
gg <- gg + geom_map(data=hex_map, map=hex_map,
                    aes(x=long, y=lat, map_id=id),
                    fill="#ffffff", color="#7f7f7f", size=0.25)
gg <- gg + geom_map(data=hex@data, map=hex_map, aes(map_id=iso3166_2, fill=bees))
gg <- gg + coord_map()
gg <- gg + scale_fill_viridis()
gg <- gg + theme_map()
gg <- gg + theme(legend.position="right")
gg

enter image description here

一般来说,它更准确,对于色盲和准确可见。将(并准确地)降级为灰度级。

答案 1 :(得分:1)

使用scale_manual,您可以创建自己的离散量表&#34; (?scale_fill_manual)。因此,错误&#34;错误:连续值[即&#34;衡量&#34;]提供给离散比例[scale_fill_manual]&#34;。

您需要一个连续的比例并尝试scale_fill_gradient。精细。但是,使用scale_fill_gradientn更容易实现所需的调色板,这会在n种颜色之间创建一个&#34;平滑颜色渐变&#34;。

一个更简单的例子:

# some data
df <- data.frame(x = 1:11, y = 1)

# an analogue to your failed attempt 
ggplot(data = df, aes(x = x, y = y, fill = x)) +
  geom_point(pch = 21, size = 20) +
  scale_fill_manual(values = myPal)
# Error: Continuous value supplied to discrete scale


# using the continuous scale_fill_gradientn instead, with the desired color vector and space
ggplot(data = df, aes(x = x, y = y, fill = x)) +
  geom_point(pch = 21, size = 20) +
  scale_fill_gradientn(colours = c("darkgreen", "yellow", "red"), space = "rgb")  

enter image description here