bus.js

var Canvas = require('canvas'),
    glob = require('glob'),
    fs = require('fs'),
    rainbowDash = require('rainbow-dash'),
    leftpad = require('leftpad'),
    width = 1000,
    height = 1000,
    radius = 100,
    c = new Canvas(width, height),
    ctx = c.getContext('2d');

console.log('parsing');

// var pos = glob.sync('data/v0/bus/positions/*.geojson').slice(0, 1000).map(function(p) {
var pos = glob.sync('data/v0/bus/positions/*.geojson').map(function(p) {
    var collection = JSON.parse(fs.readFileSync(p));
    return [+p.match(/(\d+).geojson/)[1], collection.features.length];
});

ctx.fillStyle = '#fff';
ctx.fillRect(0, 0, width, height);

console.log('done parsing');

ctx.fillStyle = '#333';
ctx.globalAlpha = 0.2;

ctx.lineTo(width/2, height/2);
pos.forEach(function(p) {
    if (p[0] - last > 1) {
        // console.log('break');
        ctx.lineTo(width/2, height/2);
        ctx.fill();
        ctx.beginPath();
    } else {
        // console.log('nonbreak');
    }
    ctx.lineTo.apply(ctx, xy(p));
    last = p[0];
});

ctx.fill();

ctx.globalAlpha = 1;

var last = -Infinity;

pos.forEach(function(p) {
    if (p[0] - last > 1) {
        // console.log('break');
        ctx.stroke();
        ctx.beginPath();
    } else {
        // console.log('nonbreak');
    }
    ctx.lineTo.apply(ctx, xy(p));
    last = p[0];
});

ctx.stroke();
ctx.beginPath();

ctx.font = '15px Monaco';

ctx.strokeStyle = '#ccc';

for (var i = 0; i < 24; i++) {
    var p = hr(i - 6, 410);
    ctx.fillText(i + 1, p[0], p[1]);
    ctx.beginPath();
    ctx.moveTo(width/2, height/2);
    var p2 = hr(i - 6, 1010);
    ctx.lineTo(p2[0], p2[1]);
    ctx.stroke();
}

ctx.beginPath();

function hr(i, radius) {
    var angle = (i / 24) * Math.PI * 2;
    return [
        (width / 2) +  (Math.cos(angle) * radius),
        (height / 2) + (Math.sin(angle) * radius)
    ];
}

ctx.strokeStyle = '#000';

pos.forEach(function(p) {
    if (p[0] - last > 1) {
        // console.log('break');
        ctx.stroke();
        ctx.beginPath();
    } else {
        // console.log('nonbreak');
    }
    ctx.lineTo.apply(ctx, xy(p));
    last = p[0];
});

function xy(p) {
    var d = new Date(p[0] * 1000 * 60),
        hrs = d.getHours() * 60,
        mins = d.getMinutes(),
        angle = ((hrs + mins) / (60 * 24)) * Math.PI * 2;

    return [
        (width / 2) +  (Math.cos(angle) * radius * (p[1] / 100)),
        (height / 2) + (Math.sin(angle) * radius * (p[1] / 100))
    ];
}

fs.writeFileSync('supply.png', c.toBuffer());

// fs.writeFileSync('supply.json', JSON.stringify(doub));