Monthly Archives: July 2015

The Moon And The Sun

Do not swear by the moon, for she changes constantly. Then your love would also change (William Shakespeare, Romeo and Juliet)

The sun is a big point ant the moon is a cardioid:

Moon&Sun

Here you have the code. It is a simple example of how to use ggplot:

library(ggplot2)
n=160
t1=1:n
t0=seq(from=3, to=2*n+1, by=2) %% n
t2=t0+(t0==0)*n
df=data.frame(x1=cos((t1-1)*2*pi/n), y1=sin((t1-1)*2*pi/n), x2=cos((t2-1)*2*pi/n), y2=sin((t2-1)*2*pi/n))
opt=theme(legend.position="none",
panel.background = element_rect(fill="white"),
panel.grid = element_blank(),
axis.ticks=element_blank(),
axis.title=element_blank(),
axis.text =element_blank())
ggplot(df, aes(x = x1, y = y1, xend = x2, yend = y2)) +
geom_point(x=0, y=0, size=245, color="gold")+
geom_segment(color="white", alpha=.5)+opt

Trigonometric Pattern Design

Triangles are my favorite shape, three points where two lines meet (Tessellate, Alt-J)

Inspired by recurrence plots and by the Gauss error function, I have done the following plots. The first one represents the recurrence plot of f\left ( x \right )= sec\left ( x \right ) where distance between points is measured by Gauss error function:

sec1This one is the same for f\left ( x \right )= tag\left ( x \right )

tan1And this one represents f\left ( x \right )= sin\left ( x \right )

sin1I like them: they are elegant, attractive and easy to make. Try your own functions. One final though: the more I use magrittr package, the more I like it. This is the code for the first plot.

library("magrittr")
library("ggplot2")
library("pracma")
RecurrencePlot = function(from, to, col1, col2) {
  opt = theme(legend.position  = "none",
              panel.background = element_blank(),
              axis.ticks       = element_blank(),
              panel.grid       = element_blank(),
              axis.title       = element_blank(),
              axis.text        = element_blank()) 
  seq(from, to, by = .1) %>% expand.grid(x=., y=.) %>% 
    ggplot( ., aes(x=x, y=y, fill=erf(sec(x)-sec(y)))) + geom_tile() + 
    scale_fill_gradientn(colours=colorRampPalette(c(col1, col2))(2)) + opt}
RecurrencePlot(from = -5*pi, to = 5*pi, col1 = "black", col2= "white")