d3-geo VS opal-d3

This tutorial will show you how to convert publicly available shapefiles to TopoJSON to create interactive maps with d3/d3-geo. I will show you how to do this without the use of the command line so you can get into experimenting with d3 as fast as possible. If you are interested in working with shapefiles and TopoJSON in a more advanced fashion, I suggest you take a look at Mike Bostock’s recent multipart tutorials on command-line cartography.

geographical data handling system

For the globe spinning, I used d3 and topojson to render the world at whatever projection/rotation/etc I give it. Then, using requestAnimationFrame, every frame I slightly rotate the world. Then the "water" behind it is just a blue circle that has hidden overflow.

Using a d3-geo we make projection and a path generator to 'draw' the geographic lines

Thanks for the compliments! The territory data is coming from https://github.com/aourednik/historical-basemaps, I use this data to render an SVG map with D3.js. This is pretty powerful since you can control every part of the rendering mechanism. With D3-geo you can easily do the projections and graticule.

It's possible to build a framework on top of Opal Ruby, like notably Hypestack, which uses uses Opal and React. There are also some wrappers like opal-jquery, and I even created opal-d3 once upon a time, but I don't actively maintain it anymore.

D3 is a JavaScript framework for data visualization. I've used it a bit a while back, even created Opal Ruby bindings, but that was many versions ago.