给定一个shapefile,我该如何成形和使用一个数据文件,以便能够使用对应于shapefile中形状区域的标识符来绘制专题图?
#Download English Government Office Network Regions (GOR) from:
#http://www.sharegeo.ac.uk/handle/10672/50
tmp_dir = tempdir()
url_data = "http://www.sharegeo.ac.uk/download/10672/50/English%20Government%20Office%20Network%20Regions%20(GOR).zip"
zip_file = sprintf("%s/shpfile.zip", tmp_dir)
download.file(url_data, zip_file)
unzip(zip_file, exdir = tmp_dir)
library(maptools)
#Load in the data file (could this be done from the downloaded zip file directly?
gor=readShapeSpatial(sprintf('%s/Regions.shp', tmp_dir))
#I can plot the shapefile okay...
plot(gor)
#and I can use these commands to get a feel for the data...
summary(gor)
attributes(gor@data)
gor@data$NAME
#[1] North East North West
#[3] Greater London Authority West Midlands
#[5] Yorkshire and The Humber South West
#[7] East Midlands South East
#[9] East of England
#9 Levels: East Midlands East of England ... Yorkshire and The Humber
#download data from http://www.justice.gov.uk/downloads/publications/statistics-and-data/courts-and-sentencing/csq-q3-2011-insolvency-tables.csv
#insolvency<- read.csv("~/Downloads/csq-q3-2011-insolvency-tables.csv")
insolvency=read.csv("http://www.justice.gov.uk/downloads/publications/statistics-and-data/courts-and-sentencing/csq-q3-2011-insolvency-tables.csv")
insolvencygor.2011Q3=subset(insolvency,Time.Period=='2011 Q3' & Geography.Type=='Government office region')
#tidy the data
require(gdata)
insolvencygor.2011Q3=drop.levels(insolvencygor.2011Q3)
names(insolvencygor.2011Q3)
#[1] "Time.Period" "Geography"
#[3] "Geography.Type" "Company.Winding.up.Petition"
#[5] "Creditors.Petition" "Debtors.Petition"
levels(insolvencygor.2011Q3$Geography)
#[1] "East" "East Midlands"
#[3] "London" "North East"
#[5] "North West" "South East"
#[7] "South West" "Wales"
#[9] "West Midlands" "Yorkshire and the Humber"
#So what next?
到此为止,我该如何下一步生成专题图/色度图,例如根据Debtors.Petition值为每个区域着色?
(我也刚刚注意到可能的陷阱-大写GOR级别不匹配:“约克郡和亨伯”和“约克郡和亨伯”)
最佳答案
没有回答问题,这是一种方法(问题代码从下面的代码开始):
#Convert factors to numeric [ http://stackoverflow.com/questions/4798343/convert-factor-to-integer ]
#There's probably a much better formulaic way of doing this/automating this?
insolvencygor.2011Q3$Creditors.Petition=as.numeric(levels(insolvencygor.2011Q3$Creditors.Petition))[insolvencygor.2011Q3$Creditors.Petition]
insolvencygor.2011Q3$Company.Winding.up.Petition=as.numeric(levels(insolvencygor.2011Q3$Company.Winding.up.Petition))[insolvencygor.2011Q3$Company.Winding.up.Petition]
insolvencygor.2011Q3$Debtors.Petition=as.numeric(levels(insolvencygor.2011Q3$Debtors.Petition))[insolvencygor.2011Q3$Debtors.Petition]
#Tweak the levels so they match exactly (really should do this via a lookup table of some sort?)
i2=insolvencygor.2011Q3
i2c=c('East of England','East Midlands','Greater London Authority','North East','North West','South East','South West','Wales','West Midlands','Yorkshire and The Humber')
i2$Geography=factor(i2$Geography,labels=i2c)
#Merge the data with the shapefile
gor@data=merge(gor@data,i2,by.x='NAME',by.y='Geography')
#Plot the data using a greyscale
plot(gor,col=gray(gor@data$Creditors.Petition/max(gor@data$Creditors.Petition)))
因此,该方法的作用是将数字数据合并到shapefile中,然后直接对其进行绘制。
也就是说,将数据文件和shapefile分开是不是更干净的方法? (我仍然不确定该怎么做?)