Analysing .NET start-up time with Flamegraphs
> Recently I gave a talk at the NYAN Conference called ‘From ‘dotnet run’ to ‘hello world’: In the talk I demonstrate how you can use PerfView to analyse where the .NET Runtime is spending it’s time during start-up:
David Rumsey Historical Map Collection
> The David Rumsey Map Collection was started over 30 years ago and contains more than 150,000 maps. The collection focuses on rare 16th through 21st century maps of North and South America, as well as maps of the World, Asia, Africa, Europe, and Oceania. The collection includes atlases, wall maps, globes, school geographies, pocket maps, books of exploration, maritime charts, and a variety of cartographic materials including pocket, wall, children’s, and manuscript maps. Items range in date from about 1550 to the present.
This is fantastic.
> In this blog post I’d like to look at these simple machines up close. I’ll explain how gears affect the properties of rotational motion and how the shape of their teeth is way more sophisticated than it may initially seem.
> Movement is important in this article so most of the visualizations are animated – you can play and pause them by tapping on the button in their bottom left corner. By default the animations are enabled, but if you find them distracting, or you want to save power, you can globally pause all animations, just make sure to unpause them as needed.
This is very neat.
OldNYC: Mapping Historical Photographs
George III's collection of military maps
> George III’s collection of military maps comprises some 3,000 maps, views and prints ranging from the disposition of Charles V’s armies at Vienna in 1532 to the Battle of Waterloo (1815).
> Most notable among these are the military maps, prints and drawings collected by his uncle, William Augustus, Duke of Cumberland (1721–65), particularly during his period as Captain General of the British army during the War of the Austrian Succession (1743–8) and the Seven Years War (1756–63).
> The second major collection, bought by George III in 1763, was that of the military prints collected by the Italian art patron, Cassiano dal Pozzo (1588–1657). In addition to these, George III acquired hundreds of maps of contemporary conflicts, such as the American War of Independence (1775–83), and the French and Napoleonic Wars (1792–1815).
Twelve Million Phones, One Dataset, Zero Privacy
> Every minute of every day, everywhere on the planet, dozens of companies — largely unregulated, little scrutinized — are logging the movements of tens of millions of people with mobile phones and storing the information in gigantic data files. The Times Privacy Project obtained one such file, by far the largest and most sensitive ever to be reviewed by journalists. It holds more than 50 billion location pings from the phones of more than 12 million Americans as they moved through several major cities, including Washington, New York, San Francisco and Los Angeles.
> Each piece of information in this file represents the precise location of a single smartphone over a period of several months in 2016 and 2017. The data was provided to Times Opinion by sources who asked to remain anonymous because they were not authorized to share it and could face severe penalties for doing so. The sources of the information said they had grown alarmed about how it might be abused and urgently wanted to inform the public and lawmakers.
A Decade of ‘Unicorns’ Ends With a Little Less Magic
> Despite their growing numbers and valuations, the performance of unicorns has been a mixed bag. On the whole, an investor in the second half of the decade was likelier to have put money into a unicorn that was unprofitable and whose value has dropped as a public company than an investor in the decade’s first half, The Wall Street Journal found.
The Deep Sea
Takes a lot of scrolling to get to the bottom.
The New York City Subway Map as You’ve Never Seen It Before
The three ins of web design: interesting and infuriatingly interactive.
Writing a Texture Painter: Part #1
> Many programmers appreciate being able to see their code render something interesting to the screen. For a while I’ve wanted to write a texture painter, where I can import a model, paint colors on it, and then export those textures back to a file. I’m using OpenGL in my code, but I’ll focus on the actual mechanics and less on the language or code.
The Berlin Wall Fell 30 Years Ago. Where Did It Go?
Evolution of the Scrollbar
And the Verge review: https://www.theverge.com/2019/11/1/20943552/scroll-bar-visual-history-30-years
> Sébastien Matos has built a fantastic interactive trip through the history of one of the most important UI elements we encounter every day: the scroll bar. He’s recreated, as faithfully as possible, 30 years of scroll bars from some of the top desktop platforms of their day, from Xerox Star to Windows 10.
> Take a minute out of your busy day to enjoy the zen of playing with old UI design. Then come back here and read The Verge’s very serious review of scroll bars through history.
Signed distance fields
> It would be fun, I thought, to be able to specify the desired cross-sections, and have something generate the required 3D shape (if it existed) in real-time.
> Dealing with all of the details of creating a mesh with the right vertices etc. sounded painful though. Fortunately, I had been reading recently about a different kind of 3D rendering technique which makes these kind of boolean operations trivial – signed distance fields.
Factorio New pathfinding algorithm
> A simple choice for this function is simply the straight-line distance from the node to the goal position – this is what we have been using in Factorio since forever, and it’s what makes the algorithm initially go straight. It’s not the only choice, however – if the heuristic function knew about some of the obstacles, it could steer the algorithm around them, which would result in a faster search, since it wouldn’t have to explore extra nodes. Obviously, the smarter the heuristic, the more difficult it is to implement.
> The simple straight-line heuristic function is fine for pathfinding over relatively short distances. This was okay in past versions of Factorio – about the only long distance pathfinding was done by biters made angry by pollution, and that doesn’t happen very often, relatively speaking. These days, however, we have artillery. Artillery can easily shoot – and aggro – massive numbers of biters on the far end of a large lake, who will then all try to pathfind around the lake. The video below shows what it looks like when the simple A* algorithm we’ve been using until now tries to go around a lake.
Incenters of chocolate-iced cakes
> Grandma made a cake whose base was a square of size 30 by 30 cm and the height was 10 cm. She put chocolate icing on top of the cake and on the sides, but not on the bottom. She wanted to divide the cake fairly among her 9 grandchildren so that each child would get an equal amount of the cake and the icing. How should she cut the cake?
Apple’s New Map, Expansion #5 Northeast U.S.
The usual before and after analysis.
Where Theory Meets Chalk, Dust Flies
> A photo survey of the blackboards of mathematicians.
> For the last year, Jessica Wynne, a photographer and professor at the Fashion Institute of Technology in New York, has been photographing mathematicians’ blackboards, finding art in the swirling gangs of symbols sketched in the heat of imagination, argument and speculation. “Do Not Erase,” a collection of these images, will be published by Princeton University Press in the fall of 2020.
Visual Information Theory
> Information theory gives us precise language for describing a lot of things. How uncertain am I? How much does knowing the answer to question A tell me about the answer to question B? How similar is one set of beliefs to another? I’ve had informal versions of these ideas since I was a young child, but information theory crystallizes them into precise, powerful ideas. These ideas have an enormous variety of applications, from the compression of data, to quantum physics, to machine learning, and vast fields in between.
> Unfortunately, information theory can seem kind of intimidating. I don’t think there’s any reason it should be. In fact, many core ideas can be explained completely visually!
The Enigma Machine
> The Enigma Machine was one of the centerpoints of World War II, and its cryptanalysis was one of the stepping stones from breaking codes as an art to cryptography as a science. The machine encrypted messages sent between parts of the German army – operators would type a key on its keyboard, the machine would scramble that, and a letter would light up on the top.
> This notebook simulates an Enigma Machine and visualizes how it works. The Enigma Machine is an especially neat thing to visualize because it was electromechanical. As you used it, it moved. Instead of circuit traces, it had beautiful real wires connecting its pieces.