coords.R

library("tidyverse")
library("geometry")

data.frame(trap_degree = c(0,0,90,90), 
           distance_m = c(100, 200, 100, 200))%>% 
  mutate(data.frame(pol2cart(theta = trap_degree, r = distance_m))) %>% 
  ggplot()+
  aes(x=y, y=x)+
  geom_point() +
  geom_text(aes(label=paste0(trap_degree,",", distance_m), vjust=1))+
  geom_hline(yintercept = 0)+
  geom_vline(xintercept = 0)
  
# 2nd question: 
# should the angle of attack of wind to the spore traps be min 0° up to 180° max??

expand_grid(trap_degrees = c(0, 90,  180, 270,  359), 
       wind_degrees = c(0, 45, 90, 135, 180, 225, 270, 315, 359))%>% 
  mutate(degree_dif = (wind_degrees - trap_degrees)) %>% 
  mutate(degree_dif2=case_when((abs(degree_dif)<=180)~abs(degree_dif),
                               (abs(degree_dif)>180)~360-abs(degree_dif))) %>% 
  ggplot()+ 
  aes(degree_dif, degree_dif2)+
  geom_point(alpha=.5)+
  ggrepel::geom_text_repel(
    aes(degree_dif, degree_dif2, label=paste0(trap_degrees,",", wind_degrees), vjust=1))+
  lims(x=c(-360,360), y=c(0,180))

Good catch.

I've found the answer. The help file for pol2cart() is incomplete. The theta needs to be provided as radians not degrees, but it doesn't state that!

Multiply your degrees by 0.01745329 and this will display as you expect.

I updated the webpage to reflect this. It made no change at all to the model's fit.

library("tidyverse")
library("geometry")

data.frame(trap_degree = c(0,0,90,90), 
           distance_m = c(100, 200, 100, 200))%>% 
  mutate(data.frame(pol2cart(theta = trap_degree * 0.01745329,
							 r = distance_m))) %>% 
  ggplot()+
  aes(x=y, y=x)+
  geom_point() +
  geom_text(aes(label=paste0(trap_degree,",", distance_m), vjust=1))+
  geom_hline(yintercept = 0)+
  geom_vline(xintercept = 0)

Excellent!

#2

👏👍