在ggplot2

如何解决在ggplot2

给出如下数据框dd：

dd <- structure(list(city = c("bj","cd","cq","dg","fs","gz","hz","jh","ks","xm","sh","tj","wz","wx","xy","yw"),nums = c(3,1,2,3,1),longitude = c(116.413383697123,104.081533510425,106.558434155377,113.758420457876,113.128512195497,113.27143134446,120.215511803722,114.423558016582,119.653436190529,120.98745249795,118.096435499767,121.480538860177,117.209523214671,120.706476890356,120.318583288106,108.715422451433,120.081580993059),latitude = c(39.9109245472996,30.6558218784164,29.5689962453389,23.0273084116434,23.0277587507889,23.135336306695,30.2530829816935,23.1163588547256,29.0846393855137,31.3908634250819,24.4854066051763,31.235929042252,39.093667843404,28.0010854044722,31.4988097326857,34.3354762933686,29.3111498754101
    )),row.names = c(NA,-17L),class = "data.frame")

我用以下代码绘制了地图：

library(mapdata)
china <- map("china",plot = F)
ggplot() + 
  geom_path(data = china,aes(long,lat,group = group),color = 'grey80',show.legend = T) +
  geom_point(data = dd,aes(x = longitude,y = latitude,size = nums),alpha = 0.8,color = '#FD9FA4') +
  coord_map("polyconic") +
  xlab('') +
  ylab('') +
  theme_economist_white(gray_bg = FALSE) +
  geom_text_repel(data = dd,label = city),size = 5,family = "STKaiti") +
  theme_bw(base_family = "STKaiti") +
  scale_x_continuous(expand = c(0,0)) +
  scale_y_continuous(expand = c(0,0)) +
  theme(panel.grid = element_blank(),panel.border = element_blank(),panel.background = element_blank(),axis.text = element_blank(),axis.ticks = element_blank(),axis.title = element_blank(),legend.position = "right",legend.title = element_text(size = 18),legend.text = element_text(size = 18),strip.text = element_text(size = 18),plot.title = element_text(size = 25,hjust = 0.5,face = "bold",margin = margin(0,10,0)),plot.subtitle = element_text(size = 20,color="black",20,plot.caption = element_text(size = 20,color = "black")
        )

legend.text情节：

但是您可能会注意到，legend.text不是原始数据的整数，如何将legend.text转换为1,3而不是1,1.5,2.5,3？

我尝试过使用dd$nums= as.numeric(as.character(dd$nums))，但没有成功。

谢谢。

解决方法

我敢肯定有很多方法可以解决此问题，但是这种方法非常简单，只需要将nums参数包装在factor中即可，即：

ggplot() + 
  geom_path(data = china,aes(long,lat,group = group),color = 'grey80',show.legend = T) +
  geom_point(data = dd,aes(x = longitude,y = latitude,size = factor(nums)),alpha = 0.8,color = '#FD9FA4') +
  guides(size = guide_legend(title = "nums"))