用xy.coords在r中绘制坐标

Question

I want to plot a series of coordinates in R (which I am just beginning to learn about) and found xy.coords as a tool to do so. however, xy.coords fails to correctly interpret the data I want to feed to it.

i imported the csv file with the data with

> objectname <- read.csv("./file", header=TRUE, sep=",")

showing the data in resulting from that directly looks like:

> chances1617$location_y
[1] -             33.0          76.0          44.0          42.0         
[6] 20.0          54.0          16.0          67.0          42.0         
[11] 16.0          44.0          31.0          17.0          90.0         
[16] 27.0          123.0         28.0          121.0         1.0   
...

> chances1617$location_x
[1] -              33.0           -36.0          -12.0         
[5] 22.0           2.0            -22.0          -16.0         
[9] -21.0          11.0           2.0            0.0           
[13] 32.0           -7.0           81.0           -17.0         
[17] -89.0          9.0            92.0           -136.0      
...

whereas xy.coords understands this as

> xy.coords(chances1617$location_x, chances1617$location_y)
$y
[1]   1 122 189 142 139  90 157  73 176 139  73 142 119  77 211 109  35 112
[19]  33   3 211 150  73  85   6 140 189 196 140 202 168 122 147  22 150 150 
...
$x
[1]   1 235  73  16 218 211  41  27  39 184 211 169 233 135 333  29 158 343
[19] 346  23  31 204 192  33 297 227 126  58 202   4  78 235  26 330 199 192

What may be going wrong there? Is the data I want to process with xz.coords in a wrong format, or am i using it wrong, or is it the wrong tool?

Answer 1

It looks like your data chances1617$location_x and chances1617$location_y are factors. Try converting them to numeric data by eg

xy.coords(as.numeric(as.character(chances1617$location_x)),
          as.numeric(as.character(chances1617$location_y)))