6 ms·
Tissot's indicatrix
- enriquto 3y agoFor a bit of context: https://en.wikipedia.org/wiki/Tissot%27s_indicatrix https://en.wikipedia.org/wiki/Tissot%27s_indicatrix This is an essential tool to teach, not only map projections, but the more general concept of Riemannian metrics! See also the Dupin indicatrix, whose wikipedia article unfortunately lacks good figures: https://en.wikipedia.org/wiki/Dupin_indicatrix https://en.wikipedia.org/wiki/Dupin_indicatrix (it makes a funny appeal to "just imagine them"...)
- selimthegrim 3y agoI’d heard of a Dupin cyclide but not this, thanks.
- Our_Benefactors 3y agoThank you. Without this, I was trying to understand how the code snippets were related to the watch brand Tissot.
- rrr_oh_man 3y agoSomewhat related (if you’re one of today’s lucky 10,000): https://xkcd.com/977/ https://xkcd.com/977/
- 082349872349872 3y agoor further afield, Spilhaus: https://www.esri.com/arcgis-blog/wp-content/uploads/2019/09/SpilhausBathymetry.jpg https://www.esri.com/arcgis-blog/wp-content/uploads/2019/09/...
- rrr_oh_man 3y ago> Spilhaus Which itself is a combination of Hammer & Spielmann, centered on Antarctica. https://www.geographyrealm.com/the-spilhaus-endless-ocean-map-projection/ https://www.geographyrealm.com/the-spilhaus-endless-ocean-ma...
- omoikane 3y agoI was looking for Dymaxion in the dropdown list and it's not there :( It doesn't have Euler Spiral[1] either, but maybe that's expecting too much. [1] http://andersk.mit.edu/euler-spiral-projection/ http://andersk.mit.edu/euler-spiral-projection/
- rrr_oh_man 3y ago> Euler Spiral AKA the "apple peel" projection.
- hiyer 3y agoAnd here I was thinking this was a new watch from Tissot :-)
- qubex 3y agoSame. What I found was far more interesting and educating.
- king_magic 3y agoHa, my first thought too. Some new kind of movement to follow the Powermatic 80, perhaps? But like someone else said, a very interesting read.
- glutamate 3y agoWhich language is used in the code boxes here? is this a JavaScript extension?
- glutamate 3y agoThe answer is probably in here https://observablehq.com/documentation/cells/observable-javascript https://observablehq.com/documentation/cells/observable-java... but i still don't see why you can do `x = { let y = 5; return y }`
- FragenAntworten 3y agoI think that's a combination of two features, named cells[1] and blocks[2]. [1] https://observablehq.com/documentation/cells/javascript#naming-referencing-cells https://observablehq.com/documentation/cells/javascript#nami... [2] https://observablehq.com/documentation/cells/javascript#expressions-variables-blocks https://observablehq.com/documentation/cells/javascript#expr...
- zokier 3y ago> Named cells look like, and function almost like, assignment expressions in vanilla JavaScript > But sometimes you want statements, such as for loops. For that you'll need curly braces, and a return statement to give the cell a value. Think of a cell as a function, except the function has no arguments So `x = { let y = 5; return y }` declares named cell x with value from the return value of that function-like code block. So basically that should be same as `x = 5`, which also is named cell declaration and not JS variable assignment.
- omoikane 3y agoSee also: https://observablehq.com/@d3/projection-comparison https://observablehq.com/@d3/projection-comparison