A class that logs locations using HTML5 geolocation

LocationHistory.coffee

window.randomly = () -> (Math.round(Math.random())-0.5)
Number::toRadians = () -> @*2*Math.PI/360

class LocationHistory
	constructor: (name = "Name", load  = false, onUpdate) ->
		if not navigator.geolocation
			return "not supported"
		@name = name
		@times = []
		@locations = []
		@EARTH_RADIUS = { kilometers: 6378.135, miles: 3963.1676 }
		if(load)
			item = localStorage.getItem(@name)
			item = JSON.parse(item)
			for k,v in item
				@times.push(k);
				@locations.push(v);
		@interval = setInterval =>
			navigator.geolocation.getCurrentPosition (position) =>
				here = "#{position.coords.latitude},#{position.coords.longitude}"
				if(@movedFrom here)
					@add(Date().valueOf(), here)
					onUpdate(position,here);
			,(error) ->
				console.log(error)
				switch(error.code)
					when 1 
						console.log("declined")
					when 3 
						console.log("timeout")
			,enableHighAccuracy: true
		,1000
		null
	haversine: (from, to, units = 'miles') ->
		if(typeof from=="string" and typeof from=="string")
			from_ = from.split /,\s*/
			from_longitude = parseFloat(from_[0]).toRadians()
			from_latitude = parseFloat(from_[1]).toRadians()
			to_ = to.split /,\s*/
			to_longitude = parseFloat(to_[0]).toRadians()
			to_latitude = parseFloat(to_[1]).toRadians()

		else
			from_longitude  = from.longitude.toRadians
			from_latitude   = from.latitude.toRadians
			to_longitude    = to.longitude.toRadians
			to_latitude     = to.latitude.toRadians

		latitude_delta  = to_latitude - from_latitude
		longitude_delta = to_longitude - from_longitude

		a = Math.pow(Math.sin(latitude_delta/2),2) +
		Math.cos(from_latitude) *
		Math.cos(to_latitude) *
		Math.pow(Math.sin(longitude_delta/2),2)

		c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a))
		d = @EARTH_RADIUS[units] * c

	add: (time,location) ->
		@times.push(time)
		@locations.push(location)
		null
	length: () ->
		@times.length
	last: () ->
		length = @times.length-1 
		length = 0 if length == -1
		[ @times[length], @locations[length] ]
	save: () ->
		hash = {}
		for i in [0..@times.length]
			hash[@times[i]] = @locations[i]
		console.log(JSON.stringify(hash))
		localStorage.setItem(@name,JSON.stringify(hash))
	movedFrom: (location) ->
		length = @locations.length - 1 
		location != @locations[@locations.length - 1 ] || length==-1
	timeAtPoint: (index=-1) ->
		(new Date() - new Date(@times[index..]))/1000
	distanceFromPoint: (index = -1) ->
		@haversine(@location[-2],@location
	stopLogging: ->
		clearInterval(@interval)

prettyTime = () ->
	now = new Date()
	meridian = if now.getHours()<12 then "AM" else "PM"
	h = if meridian=="AM" then now.getHours() else now.getHours()-12
	date = now.toDateString().split(" ")[1] + " " + now.getDate()
	"#{date} #{h}:#{now.getMinutes()}  #{meridian}"

window.hash2 = new LocationHistory("test2", false, 
	(raw, here) -> document.getElementsByTagName("ul")[0].innerHTML+= "<li><b>#{here}</b><em>#{prettyTime()}</em></li>")