The Earth is round, and maps are flat. That’s a problem for map makers. And a source of endless entertainment for geeks.
Carlos A. Furuti has an excellent website with many projections and clear explanations of the tradeoffs of each. The main projection page has links to all types, including two of my favorites: Other Interesting Projections, and Projections on 3D Polyhedra. Enjoy!
In R, the packages maps and mapproj are your entrée to this world. I created the above map (a Mollweide projection, which is a useful favorite), with:
map ("world", projection="mollweide", regions="", wrap=TRUE, fill=TRUE, col="green")
map.grid (labels=FALSE, nx=36, ny=18)
So far, when I’ve written on Data Science topics I’ve written about the fun part: the statistical analysis, graphs, conclusions, insights, etc. For this next series of postings, I’m going to concentrate more on what we can call Real Data Science®: the less glamorous side of the job, where you have to beat your data and software into submission, where you don’t have access to the tools or data you need, and so on. In other words, where you spend the vast majority of your time as a Data Scientist.
I’ll start the series with a review of Kaiser Fung’s Numbersense, published in 2013. It’s not mainly about Real Data Science, but I’ll start with it because it’s a great book that illustrate several common data pitfalls, and in the epilogue Kaiser shares one of his own Real Data Science stories and I found myself nodding my head and saying, “Yup, that’s how I spent several days in the last couple of weeks!”
I like to read various Stack Exchange websites, and one of them has a wonderful discussion of how you might divide a sandwich between three people fairly. Most of us are familiar with the two-person version: one person cuts and the other person gets the first choice. But what about if there are three people, or more?
Several years ago I became interested in mathematical knot theory, so I got a book called The Knot Book by Adams. I also got the Ashley Book of Knots by Clifford Ashley, which is a 600-page encyclopedia of actual knots in ropes/string/etc. I’d forgotten about both books until last night, when a key plastic piece on our bedroom blinds broke: the part that joins the lower single cord to the upper multiple cords that actually go to the blinds.
I whipped out the Ashley Book and found the perfect bend, #1463, which is good for joining two cords that have different thickness. I’ve shown my results below, but note that the actual knot is in the upper left and the rest of it is just my quick work to make sure that the thicker piece stays bent and doesn’t straighten out and try to pull through. I don’t think Ashley would approve of that part.
When visitors come to the Washington, DC, area I like to have an off-the-beaten-path option for them. Something that most people would just walk or drive by and not notice. One of these options used to be the Einstein Statue, but recently they’ve redone the landscaping so it’s much harder to miss as you drive down Constitution Avenue.
It turns out that there is a “secret” underground “lair” in DC that you can enter and feel almost like you’re in a James Bond movie. In the photo, below, note the inconspicuous little building between the Smithsonian Castle (on the left) and the Freer Gallery (on the right). Looks like a visitor’s welcome center or something, right?
Turns out that what we called “heat lighting” as kids — lightning that has no accompanying thunder — is simply lightning that’s more than about 10 miles away. Tonight, while we were out walking, there was a huge lightning storm about 25 miles north of us. There was so much lightning that it looked like it was a timelapse video. I taped 90 seconds on my phone and uploaded it to Youtube.