hackernews seems like the perfect place for this course. How many of us need GIS data? Or need to compute the rate of change... Can't use the (x^n)' = n x^

hackernews seems like the perfect place for this course. How many of us need GIS data? Or need to compute the rate of change... Can't use the (x^n)' = n x^(n-1) on real data! I need to take a derivative of some GIS numbers have to compute a discrete gradient. In fact that's what I did to draw this figure of Puerto Rico http://s11.postimg.org/s8ph73t8z/birth_rate.png http://s11.postimg.org/s8ph73t8z/birth_rate.png