Looking for formula for the Robinson projection

Question

I'm looking for a source that describes how the Robinson projection is calculated. I'm going to use this for converting long/lat into Robinson coordinates in both R and in javascript.

Answer 1

You can use proj4 library which is present in R. I haven't used it before so you have to find out how to parse the options.

You can project coords in the Robinson transformation with proj4 like this:

$ proj +proj=robin +lon_0=90w
  10 45
  846701.55      4805073.65
  45d15n 71d07w
  3031002.67    -7374243.09

you can find more information for more options and other projections and as well how to read and project files with coordinates in the manual

Answer 2

if you are looking for description of Robinson here it is: http://en.wikipedia.org/wiki/Robinson_projection and algorithm in JS you can download from here: https://github.com/afar/robinson_projection and script descrition is here: http://www.flashmap.org/robinson-projection-in-as3-gpl/