apburnes

#Topology in Geography

Topology is a broad branch of mathematics used to describe the fundamental structure of a shape or object within a space. Objects can be manipulated by stretching or compressing the shape’s components, but the tearing of or addition to its structure will break topology. According to the rules of topology, a doughnut and a coffee mug are equal.

###Topology example: ![Alt text] (http://i.imgur.com/sBP9p.gif)

Geography utilizes topology to project geometric objects from a 3D sphere onto a 2D coordinate system while allowing the shape to stay intact with some distortion.

###3D Sphere projections to 2D plane:

BretCameron

const { google } = require('googleapis');
const fs = require('fs');

const credentials = require('./credentials.json');

const scopes = [
  'https://www.googleapis.com/auth/drive',
  'https://www.googleapis.com/auth/spreadsheets',
];

ibussieres

echo "deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main" | sudo tee /etc/apt/sources.list.d/pgdg.list
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
sudo apt-get update
sudo apt-get install postgresql-9.3 postgresql-server-dev-9.3 postgresql-contrib-9.3 -y
 
sudo su - postgres -c "psql template1 -p 5433 -c 'CREATE EXTENSION IF NOT EXISTS hstore;'"
sudo su - postgres -c "psql template1 -p 5433 -c 'CREATE EXTENSION IF NOT EXISTS \"uuid-ossp\";'"
sudo su - postgres -c "service postgresql stop"
sudo su - postgres -c '/usr/lib/postgresql/9.3/bin/pg_upgrade -b /usr/lib/postgresql/9.1/bin -B /usr/lib/postgresql/9.3/bin -d /var/lib/postgresql/9.1/main/ -D /var/lib/postgresql/9.3/main/ -O "-c config_file=/etc/postgresql/9.3/main/postgresql.conf" -o "-c config_file=/etc/postgresql/9.1/main/postgresql.conf"'
 

avinmathew

import React from "react"
import { Route, Switch } from "react-router-dom"

const AppRoute = ({ component: Component, layout: Layout, ...rest }) => (
  <Route {...rest} render={props => (
    <Layout>
      <Component {...props} />
    </Layout>
  )} />
)

markerikson

// copy-pasta'd from isarray
var toString = {}.toString;

const isArray = Array.isArray || function (arr) {
  return toString.call(arr) == '[object Array]';
};


export function batchedSubscribe() {
  let currentListeners = [];

tmcw

Moral Concerns

JSONP is not actually JSON with padding, it's Javascript code that's executed. JSON is not a real subset of Javascript and the way it is not is important to us: via UTFGrid, we are all UTF-8 masters.

JSONP is not safe: it's Javascript that's executed. It's trivial to XSS with JSONP, because JSONP is XSS. Just have a call like mapbox.load('foo.tilejson', …) and if foo.tilejson gets replaced with destroyYoursite(), it gets run. Compare to JSON.parse, which is, on purpose, not eval.

Practical Concerns

JSONP is questionable in terms of performance. To be fast, you want to have the same callback all the time so that you can cache the response. But this leads to a page like

amysimmons

#Understanding closures, callbacks and promises

For a code newbie like myself, callbacks, closures and promises are scary JavaScript concepts.

10 months into my full-time dev career, and I would struggle to explain these words to a peer.

So I decided it was time to face my fears, and try to get my head around each concept.

Here are the notes from my initial reading. I'll continue to refine them as my understanding improves.

yumminhuang

#!/usr/bin/env python
#coding=utf-8

import apt
import apt_pkg
from time import strftime
import os
import subprocess
import sys

muminoff

import sys
from PIL import Image
from math import pi,sin,cos,tan,atan2,hypot,floor
from numpy import clip

# get x,y,z coords from out image pixels coords
# i,j are pixel coords
# face is face number
# edge is edge length
def outImgToXYZ(i,j,face,edge):

joyrexus

A quick overview of the node.js streams interface with basic examples.

This is based on @brycebaril's presentation, Node.js Streams2 Demystified

Overview

Streams are a first-class construct in Node.js for handling data.

Think of them as as lazy evaluation applied to data.