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Draggable night sky map
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<html> | |
<head> | |
<meta charset="utf-8"> | |
<link href="stars.css" rel="stylesheet"> | |
</head> | |
<body> | |
<script src="http://d3js.org/d3.v3.min.js"></script> | |
<script src="stars.js"></script> | |
</body> | |
</html> |
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body { | |
background: #113; | |
} | |
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var width = 960, | |
height = 500; | |
var projection = d3.geo.stereographic() | |
.scale(600) | |
var fixedProjection = d3.geo.stereographic() | |
.scale(600) | |
.rotate([0, 0]) | |
var canvas = d3.select("body").append("canvas") | |
.attr("width", width) | |
.attr("height", height) | |
var c = canvas.node().getContext("2d") | |
function getRetinaRatio() { | |
var devicePixelRatio = window.devicePixelRatio || 1 | |
var backingStoreRatio = c.webkitBackingStorePixelRatio || | |
c.mozBackingStorePixelRatio || | |
c.msBackingStorePixelRatio || | |
c.oBackingStorePixelRatio || | |
c.backingStorePixelRatio || 1 | |
return devicePixelRatio / backingStoreRatio | |
} | |
var ratio = getRetinaRatio() | |
var scaledWidth = width * ratio | |
var scaledHeight = height * ratio | |
canvas.node().width = scaledWidth | |
canvas.node().height = scaledHeight | |
canvas | |
.style("width", width + 'px') | |
.style("height", height + 'px') | |
c.scale(ratio, ratio) | |
var path = d3.geo.path() | |
.projection(projection) | |
.context(c) | |
var graticule = d3.geo.graticule() | |
.step([15, 15]) | |
var bgRGB = d3.rgb('#113') | |
d3.json("/erohinaelena/raw/ec635d68e8bf55586d40/starData.json", function(error, data) { | |
var geoConstellations = [] | |
var starsMag = [] | |
data = data.map(function(constellation) { | |
constellation.stars = constellation.stars.filter(function(star) { | |
if (star.mag < 6) starsMag.push(star.mag) | |
return star.mag < 6 | |
}) | |
return constellation | |
}) | |
var minMaxMag = d3.extent(starsMag) | |
var opacityScale = d3.scale.linear() | |
.domain(minMaxMag) | |
.range([1, 0.4]) | |
var magScale = d3.scale.linear() | |
.domain(minMaxMag) | |
.range([2.7, 1.7]) | |
data.forEach(function (constellation) { | |
var geometries = [] | |
constellation.stars.map(function (star) { | |
var rgb = d3.rgb(star.color) | |
var rgba = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + opacityScale(star.mag) + ')' | |
geometries.push({ | |
type: 'Point', | |
coordinates: [-star.ra, star.dec], | |
properties: { | |
color: rgba, | |
mag: magScale(star.mag) | |
} | |
}) | |
}) | |
var lines = constellation.lines.map(function (line) { | |
var p1 = [-line.ra1, line.dec1] | |
var p2 = [-line.ra2, line.dec2] | |
return [p1, p2] | |
}) | |
geometries.push({ | |
type: "MultiLineString", | |
coordinates: lines | |
}) | |
if (constellation.name == 'Serpens'){ | |
var bound1 = constellation.boundary[0].map(function (coords) { | |
return [-coords[0], coords[1]] | |
}) | |
var bound2 = constellation.boundary[1].map(function (coords) { | |
return [-coords[0], coords[1]] | |
}) | |
geometries.push({ | |
type: "LineString", | |
coordinates: bound1 | |
}) | |
geometries.push({ | |
type: "LineString", | |
coordinates: bound2 | |
}) | |
} else { | |
var boundLines = constellation.boundary.map(function (coords) { | |
return [-coords[0], coords[1]] | |
}) | |
geometries.push({ | |
type: "LineString", | |
coordinates: boundLines | |
}) | |
} | |
geometries = { | |
type: 'GeometryCollection', | |
geometries: geometries | |
} | |
var geoConstellation = { | |
type: 'Feature', | |
geometry: geometries, | |
properties: { | |
name: constellation.name, | |
zodiac: constellation.zodiac, | |
center: d3.geo.centroid(geometries) | |
} | |
} | |
geoConstellations.push(geoConstellation) | |
}) | |
draw(geoConstellations, [30, -70]) | |
var raStart, decStart | |
function getStart() { | |
raStart = projection.invert(d3.mouse(this))[0] | |
decStart = fixedProjection.invert(d3.mouse(this))[1] | |
} | |
function move() { | |
var raFinish = projection.invert(d3.mouse(this))[0] | |
var decFinish = fixedProjection.invert(d3.mouse(this))[1] | |
var raRotate = raFinish - raStart | |
var decRotate = decFinish - decStart | |
var rotate = projection.rotate() | |
var newCenter = [rotate[0] + raRotate, rotate[1] + decRotate] | |
draw(geoConstellations, newCenter) | |
decStart = fixedProjection.invert(d3.mouse(this))[1] | |
} | |
var drag = d3.behavior.drag() | |
.on("dragstart", getStart) | |
.on("drag", move) | |
canvas.call(drag) | |
}) | |
function makeRadialGradient(x, y, r, color) { | |
var radialgradient = c.createRadialGradient(x, y, 0, x, y, r) | |
radialgradient.addColorStop(0.2, color) | |
radialgradient.addColorStop(0.5,'rgba(' + bgRGB.r + ',' + bgRGB.g + ',' + bgRGB.b + ',0)') | |
radialgradient.addColorStop(0.5,'rgba(' + bgRGB.r + ',' + bgRGB.g + ',' + bgRGB.b + ',1)') | |
radialgradient.addColorStop(1,'rgba(' + bgRGB.r + ',' + bgRGB.g + ',' + bgRGB.b + ',0)') | |
c.fillStyle = radialgradient | |
} | |
function distance(p) { | |
var center = [width / 2, height / 2] | |
var xRotate = center[0] - p[0] | |
var yRotate = center[1] - p[1] | |
return Math.sqrt(Math.pow(xRotate, 2) + Math.pow(yRotate, 2)) | |
} | |
function draw(constellations, center) { | |
var min = 0, | |
minDistance = distance(projection(constellations[0].properties.center)) | |
if (center) projection.rotate(center) | |
c.clearRect(0, 0, width, height) | |
c.strokeStyle = "#fff" | |
c.lineWidth = .1 | |
c.beginPath(), path(graticule()), c.stroke() | |
c.lineWidth = .4 | |
c.beginPath(), path({type: "LineString", coordinates: [[-180, 0], [-90, 0], [0, 0], [90, 0], [180, 0]]}), c.stroke() | |
c.strokeStyle = "#f2f237" | |
c.beginPath(), path({type: "LineString", coordinates: [[-180, 0], [-90, 23.26], [0, 0], [90, -23.26], [180, 0]]}), c.stroke() | |
constellations.forEach(function(constellation, i) { | |
var currentDistance = distance(projection(constellations[i].properties.center)) | |
if (currentDistance < minDistance) { | |
min = i | |
minDistance = currentDistance | |
} | |
constellation.geometry.geometries.forEach(function(geo) { | |
if (geo.type == 'Point') { | |
makeRadialGradient( | |
projection(geo.coordinates)[0], | |
projection(geo.coordinates)[1], | |
geo.properties.mag, | |
geo.properties.color) | |
path.pointRadius([geo.properties.mag]) | |
c.beginPath(), path(geo), c.fill(); | |
} else if (geo.type == 'LineString') { | |
c.strokeStyle = '#000' | |
c.beginPath(), path(geo),c.stroke() | |
} else if (geo.type == 'MultiLineString') { | |
c.strokeStyle = (constellation.properties.zodiac)? '#f2f237':"#999" | |
c.beginPath(), path(geo), c.stroke(); | |
} | |
}) | |
}) | |
c.strokeStyle = "#f00" | |
c.lineWidth = 1.2 | |
constellations[min].geometry.geometries.forEach(function(geo) { | |
if (geo.type == 'LineString') { | |
c.beginPath(), path(geo), c.stroke() | |
} | |
}) | |
c.fillStyle = '#fff' | |
c.textAlign = "center" | |
c.font = "18px sans-serif" | |
c.fillText(constellations[min].properties.name, width / 2, 280) | |
} |
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