我正在努力產生一個面圖/格圖的各分佈圖,每個圖顯示不同的模型運行如何影響一個變量被映射到多個多邊形。問題在於輸出圖形會在每個繪圖中的多邊形之間產生奇怪的線條(請參見下圖)。ggplot2面shapefile多邊形的產生奇怪的線
雖然我已經操縱Shapefile並將其轉換爲具有適合ggplot2屬性的數據框,但我不熟悉如何使用該軟件包的詳細信息,並且聯機文檔僅限於這種複雜的軟件包。我不確定哪個參數導致此問題,但我懷疑它可能是aes參數。
腳本:出現
library(rgdal, tidyr, maptools, ggplot2, dplyr, reshape2)
setwd('D:/path/to/wd')
waterloo <- read.table("waterloo-data.txt", header=TRUE, sep=',', stringsAsFactors=FALSE)
waterloo <- data.frame(waterloo$DAUID, waterloo$LA0km, waterloo$LA4_exp, waterloo$LA20km, waterloo$LA30km, waterloo$LA40km, waterloo$LA50km)
colnames(waterloo) <- c("DAUID", "LA0km", "LA10km","LA20km", "LA30km", "LA40km", "LA50km")
## Produces expenditure measurements by ID variable DAUID, using reshape2/melt
wtidy <- melt(waterloo, id.vars=c("DAUID"), measure.vars = c("LA0km", "LA10km", "LA20km", "LA30km", "LA40km", "LA50km"))
colnames(wtidy) <- c("DAUID", "BufferSize", "Expenditure")
wtidy$DAUID <- as.factor(wtidy$DAUID) # for subsequent join with wtrl_f
### READ SPATIAL DATA ###
#wtrl <- readOGR(".", "Waterloo_DA_2011_new")
wtrl <- readShapeSpatial("Waterloo_DA_2011_new")
wtrl$id <- row.names(wtrl)
wtrl_f <- fortify(wtrl)
wtrl_f <- left_join(wtrl_f, [email protected], by="id")
# Join wtrl fortified (wtrl_f) to either twaterloo or wtidy
wtrl_f <- left_join(wtrl_f, wtidy, by="DAUID")
### PLOT SPATIAL DATA ###
ggplot(data = wtrl_f, # the input data
aes(x = long.x, y = lat.x, fill = Variable/1000, group = BufferSize)) + # define variables
geom_polygon() + # plot the DAs
geom_path(colour="black", lwd=0.05) + # polygon borders
coord_equal() + # fixed x and y scales
facet_wrap(~ BufferSize, ncol = 2) + # one plot per buffer size
scale_fill_gradient2(low = "green", mid = "grey", high = "red", # colors
midpoint = 10000, name = "Variable\n(thousands)") + # legend options
theme(axis.text = element_blank(), # change the theme options
axis.title = element_blank(), # remove axis titles
axis.ticks = element_blank()) # remove axis ticks
輸出圖形如下:
奇怪!我取得了很好的進展,但我不知道ggplot在哪裏獲得這些線。任何幫助,將不勝感激!
PS;作爲另外一個無關的問題,多邊形線條相當不規則。我將如何平滑這些線?
如果你能提供一個最小的,可重複的例子,它會容易得多。最小含義只是足夠的代碼和數據來顯示問題。可重複的意思是,我可以將您的代碼完全按照提供的方式粘貼到新的R會話中,並無誤地運行它(除了錯誤,您當然需要幫助......) – bdemarest 2015-02-11 23:06:17