Dear Roger, I have a problem on converting the coordinates into interval [0,1], hoping that you can give me a hand. My data consist of points(cases), lines(rivers) and polygon (guichi city), and i want to change their coordinates into interval [0,1]. I have put the data in the attachment, so that you can use it. The following is the programs to read the data and one possible method for conversion:
library(sp) library(foreign) library(mgcv) library(maptools) #read the polygon containing the studied points guichi <- readShapePoly("e:/guichi.shp") #boundary polygons containing the points point_poly <- getPolygonCoordsSlot(getPolygonsPolygonsSlot(getSpPpolygonsSlot(guichi)[[1]])[[1]]) #get the coordinates of guichi #plot(point_poly,xlab="x", ylab="y",type="l") #read the lines of two rivers in the guichi rivers <- readShapeLines("e:/qiupu.shp") #change the coordinates??difficult #plot(rivers,add=T) #read the points of cases and controls case_control <- read.csv("e:/casecontrol.csv",sep=",", header=TRUE) #plot(case_control$x,case_control$y) *#Plot the whole figure* plot(point_poly,xlab="x", ylab="y",type="l") plot(rivers,add=T) points(case_control$x,case_control$y,add=T) ################################################################################### #one of the possible methods to convert the x/y coordinates into interval [0,1] *# But it seems there is a problem: it convert the x/y coordinates into interval [0,1], respectively. # In my opinion, they should be expand or shrink according to the same minimum/maximum value*. st <- function(x)(x-min(x))/(max(x)-min(x)) case_control[,c(8,9)] <- data.frame(lapply(case_control[,c(6,7)],st)) ################################################################################### *Q1. The main problem is on the rivers, which has multiple lines. There are difficulties for conversion. Q2. when i convert the x/y coordinates, i'm not very sure whether i should use the same scale of conversion or not. * Could you please help us to solve it? Any suggestions/help are greatly appreciated. -- With Kind Regards, oooO::::::::: (..)::::::::: :\.(:::Oooo:: ::\_)::(..):: :::::::)./::: ::::::(_/:::: ::::::::::::: [***********************************************************************] Zhi Jie,Zhang ,PHD Tel:86-21-54237149 Dept. of Epidemiology,School of Public Health,Fudan University Address:No. 138 Yi Xue Yuan Road,Shanghai,China Postcode:200032 Email:[EMAIL PROTECTED] Website: www.statABC.com [***********************************************************************] oooO::::::::: (..)::::::::: :\.(:::Oooo:: ::\_)::(..):: :::::::)./::: ::::::(_/:::: :::::::::::::
casecontrol.rar
Description: Binary data
_______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo