Where we sketch things about data science

It took me a while to get Spark running on MAC with the help of the instructions from John Ramey’s post. I’m using MAC OS version 10.11.2 with 8G RAM, spark 1.6.0, but I got stuck while I’d followed steps presented in that blog, the problems were

Thanks to the info provided here and here, I gonna note it down here for plotting the colorbar in Python Matplotlib without using imshow() or scatter() to make a fake drawing first and clean it off later.