How to connect the end point and the start point of geom_line in the polar region (coord_polar)?

Question

I am a little stuck in getting the endpoint of the line in the polar section to connect with the starting point.

My details:

df <- structure(list(ri = c(0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360),
                 n = c(329L, 315L, 399L, 700L, 919L, 757L, 656L, 918L, 1117L, 976L, 878L, 803L, 811L, 1072L, 1455L, 1642L, 1891L, 1688L, 1553L, 1841L, 2061L, 2321L, 2498L, 2080L, 1595L, 1080L, 1002L, 953L, 729L, 604L, 538L, 489L, 535L, 455L, 328L, 351L, 329L),
                 d = c(0.008581340149717, 0.00821617673909074, 0.0104071572028483, 0.0182581705313128, 0.0239703695975378, 0.0197449072745768, 0.017110514097916, 0.0239442864967787, 0.0291348235478234, 0.0254571063408018, 0.022900962466418, 0.0209447299094916, 0.0211533947155638, 0.0279610840136675, 0.0379509116043715, 0.0428284514463079, 0.0493231435353035, 0.0440282740812228, 0.0405070554787553, 0.0480189884973526, 0.0537572706643366, 0.0605388768616813, 0.0651555856960275, 0.0542528495787579, 0.0416025457106341, 0.0281697488197397, 0.0261352669605363, 0.0248571950233444, 0.0190145804533243, 0.015754192858447, 0.0140327082083518, 0.0127546362711599, 0.0139544589060748, 0.0118678108453533, 0.00855525704895798, 0.0091551683664154, 0.008581340149717)),
            .Names = c("ri", "n", "d"), row.names = c(NA, 37L), class = c("tbl_df", "tbl", "data.frame"))

My first attempt to make a polar graph with this code:

ggplot(df, aes(x=ri, y=d)) +
  geom_line() +
  scale_x_continuous(breaks=seq(0,360,10)) +
  coord_polar() +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

It gives more or less what I want. However, I like to have the y axis starting with 0. So I used the following code:

ggplot(df, aes(x=ri, y=d)) +
  geom_line() +
  scale_x_continuous(breaks=seq(0,360,10)) +
  scale_y_continuous(limits=c(0,0.07), breaks=seq(0,0.06,0.01)) +
  coord_polar() +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

Unfortunately, now the line ends on 350and does not connect to 0/360:

Next I tried:

ggplot(df, aes(x=ri, y=d)) +
  geom_polygon(fill=NA, color="black") +
  scale_x_continuous(breaks=seq(0,360,10)) +
  scale_y_continuous(limits=c(0,0.07), breaks=seq(0,0.06,0.01)) +
  coord_polar() +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

This code connects the endpoint to the startpoint, but also creates a circle:

I also tried geom_path, but it gave the same result as geom_polygon. Analyzing the problem further, I tried to make a normal plot with:

ggplot(df, aes(x=ri, y=d)) +
  geom_line() +
  scale_x_continuous(expand=c(0,0), breaks=seq(0,360,10)) +
  scale_y_continuous(limits=c(0,0.07), breaks=seq(0,0.06,0.01)) +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

which gives:

, 350 360 . geom_plygon:

ggplot(df, aes(x=ri, y=d)) +
  geom_polygon(fill=NA, color="black") +
  scale_x_continuous(expand=c(0,0), breaks=seq(0,360,10)) +
  scale_y_continuous(limits=c(0,0.07), breaks=seq(0,0.06,0.01)) +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

:

, geom_path geom_polygon . , , -, y coord_polar.

:

• y, 0 geom_line coord_polar?
• geom_polygon/geom_path coord_polar?

:
ri=0. . ri=360.

Answer 1

, , :

• ri=360 ( ri=0) df <- df[df$ri!=360,]

• ri group=1 aes.

• start=-pi*1/36 coord_polar, 0

ggplot :

ggplot(df, aes(x=factor(ri), y=d, group=1)) +
  geom_polygon(fill=NA, color="black") +
  scale_y_continuous(limits=c(0,0.07), breaks=seq(0,0.06,0.01)) +
  coord_polar(start=-pi*1/36) +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

:

Answer 2

, y. :

ggplot(dat, aes(x=ri, y=d)) +
  geom_line() +
  scale_x_continuous(expand=c(0,0), breaks=seq(0,360,10)) +
  scale_y_continuous(breaks=seq(0,0.06,0.01)) +
  coord_polar() +
  theme_bw() +
  theme(panel.grid.minor=element_blank())

, > 0 ylim(0, 0.07), ...