# Metar Weather Grabber **URL:** \ **Category:** Ruby\ **Created:** [April 13, 2006, 11:25pm UTC](https://www.ruby-forum.com/t/metar-weather-grabber/57778 "2006-04-13T23:25:34Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![supasta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ebca7d/32.png) [@supasta](https://www.ruby-forum.com/u/supasta)\ **Post date:** [April 13, 2006, 11:25pm UTC](https://www.ruby-forum.com/t/metar-weather-grabber/57778/1 "2006-04-13T23:25:34Z")
I don’t want to pay money to get weather feeds from a bunch of different countries. So I took my hand at writing my own. It is for an ajax service that grabs the XML. If you use this, expand on it. If you expand on it, post it back on here. There are somethings I haven’t gotten to yet. The usage of the weather codes needs to get better too. #!/usr/bin/ruby require ‘rexml/document’ require ‘open-uri’ require ‘pp’ include REXML class Weather attr\_reader :wind, :temperature, :dew\_point, :sky, :sky\_icon def initialize(metar\_string) @metar\_string = metar\_string @wind = self.set\_wind() @temperature, @dew\_point = self.set\_temperature() @sky, @sky\_icon = self.set\_sky() end def set\_wind sample\_string = $& if @metar\_string =~ /(\d{3}|VRB)[G]{0,1}\d{1,4}KT/ ``` direction = self.get_cardinal_direction(sample_string[0...3]) speed = ``` sample\_string[sample\_string.rindex(/\d{1,4}KT/)…sample\_string.length-3].to\_i ``` "#{direction} at #{speed}mph" ``` end def get\_cardinal\_direction(degrees) case degrees.to\_i when 0: “Variable” when 1…4: “N” when 5…35: “NNE” when 36…55: “NE” when 56…85: “ENE” when 86…95: “E” when 96…125: “ESE” when 126…135: “SE” when 136…175: “SSE” when 176…185: “S” when 185…215: “SSW” when 216…225: “W” when 226…265: “WSW” when 265…275: “W” when 275…295: “WNW” when 296…305: “NW” when 306…346: “NNW” when 347…370: “N” else “Gusty” end end def set\_temperature sample\_string = $&.strip if @metar\_string =~ / [M]{0,1}\d{2}/[M]{0,1}\d{2} / ``` celcius = sample_string[0..2].to_i fahrenheit = ( ( celcius.to_i * 9 ) / 5 + 32 ) dew_point_celcius = ``` sample\_string[3…sample\_string.length-1].to\_i dew\_point\_fahrenheit = ( ( dew\_point\_celcius \* 9 ) / 5 + 32) ``` ["#{fahrenheit} F (#{celcius} C)", "#{dew_point_fahrenheit} F ``` (#{dew\_point\_celcius} C)"] end def set\_sky sky = $&.strip if @metar\_string =~ /(SKC|FEW|SCT|BKN|OVC|CLR)[CB]{0,1}/ sky = $&.strip if @metar\_string =~ /(RA|DZ|SN|GR|SQ|GS|SG|IC|PE|BR|FG|FU|HZ|VA|DU|SA|SS|DS|FC|MI|BC|DR|BL|SH|TS|FZ)+{1}/ ``` weather_codes = { "SKC"=> ["Scattered Clouds", 30], "FEW"=> ["Sunny" , 32], "SCT"=> ["Partly Cloudy" , 29], "BKN"=> ["Mostly Cloudy" , 28], "OVC"=> ["Overcast" , 26], "CLR"=> ["Sunny" , 32], "RA"=> ["Raining" , 40], "DZ"=> ["Drizzle" , 39], "SN"=> ["Snow" , 16], "GR"=> ["Hail" , 35], "SQ"=> ["Squalls" , nil], "GS"=> ["Small Hail" , 35], "SG"=> ["Snow Grains" , 15], "IC"=> ["Diamond Dust" , nil], "PE"=> ["Ice Pellets" , nil], "BR"=> ["Mist" , nil], "FG"=> ["Fog" , 20], "FU"=> ["Smoke" , 22], "HZ"=> ["Haze" , 21], "VA"=> ["Volcanic Ash" , nil], "DU"=> ["Widespead dust" , nil], "SA"=> ["Sand" , nil], "SS"=> ["Sandstorm" , nil], "DS"=> ["Duststorm" , nil], "FC"=> ["Funnel Cloud" , nil], "MI"=> ["Shallow" , nil], "BC"=> ["Patches" , nil], "DR"=> ["Drifting" , nil], "BL"=> ["Blowing" , nil], "SH"=> ["Showers" , nil], "TS"=> ["Thunderstorm" , 1], "FZ"=> ["Supercooled(Freezing)", nil], "+" => ["Heavy" , nil], "TCU"=> ["Towering Cumulonimbs", nil] } icon = '' weather_codes.each do | code, description | sky = sky.gsub(code, description[0]) icon = description[1] if !description[1].nil? end [sky, icon] ``` end end # Set up the XML document xml\_write = REXML::Document.new(’’) xml\_write.elements["//method"].text = “updateWeather” #Array of Cities and Local from the Weather xml information cities\_url = {“New York, NY” =\> “ftp://weather.noaa.gov/data/observations/metar/stations/KLGA.TXT”, “London, UK” =\> “ftp://weather.noaa.gov/data/observations/metar/stations/EGLL.TXT”} cities\_url.each do |location, url| current\_weather = Element.new() current\_weather.add\_element(“CurrentWeather”) current\_weather.elements["//CurrentWeather"].add\_attribute(“label”, location) element\_write = current\_weather.elements["//CurrentWeather[@label=’"+location+"’]"] metar = Document.new(open(url)) weather = Weather.new(metar.to\_s.gsub("\n", " ")) element\_write.add\_element(“DewPoint”).text = weather.dew\_point element\_write.add\_element(“Temperature”).text = weather.temperature element\_write.add\_element(“Wind”).text = weather.wind element\_write.add\_element(“SkyConditions”).text = weather.sky element\_write.add\_element(“SkyConditionsIcon”).text = weather.sky\_icon element\_write.add\_element(“RelativeHumidity”).text = metar[0] xml\_write.elements["//result"].add\_element(current\_weather.elements["//CurrentWeather"]) end xml\_writable = File.new(“public\_html/weather.xml”, “w+”) xml\_write.write(xml\_writable, -1, true) ---
**Author:** ![supasta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ebca7d/32.png) [@supasta](https://www.ruby-forum.com/u/supasta)\ **Post date:** [April 14, 2006, 12:09am UTC](https://www.ruby-forum.com/t/metar-weather-grabber/57778/2 "2006-04-14T00:09:27Z")
Chris W. wrote: > I don’t want to pay money to get weather feeds from a bunch of different > countries. So I took my hand at writing my own. It is for an ajax > service that grabs the XML. > > If you use this, expand on it. If you expand on it, post it back on > here. There are somethings I haven’t gotten to yet. The usage of the > weather codes needs to get better too. Hi Chris, is there something wrong with the decoded data? * * * require ‘open-uri’ ## url = ‘ftp://weather.noaa.gov/data/observations/metar/decoded/KLGA.TXT’ open(url) do |f| weather = f.read.to\_a.map {|line| line.strip.split(’:’)} label = weather.shift.first.split(’,’).first date = weather.shift.first puts %Q[] weather.each do |w| key = w.first.tr(’()’, ’ ‘).delete(’ ') puts %Q[\<#{key}\>#{w[1].strip}\] end puts ‘’ end ## output: ## from the NW (320 degrees) at 9 MPH (8 KT) 10 mile(s) partly cloudy 75.0 F (23.9 C) 35.1 F (1.7 C) 23% … cheers Simon ---
**Author:** ![supasta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ebca7d/32.png) [@supasta](https://www.ruby-forum.com/u/supasta)\ **Post date:** [April 14, 2006, 4:14am UTC](https://www.ruby-forum.com/t/metar-weather-grabber/57778/3 "2006-04-14T04:14:10Z")
Nope. I guess I just wanted to learn how to use regular expressions. I wish I would have found those a couple of hours ago. Thanks for the post, that will help a lot. Simon Kröger wrote: > Chris W. wrote: > > > I don’t want to pay money to get weather feeds from a bunch of different > > countries. So I took my hand at writing my own. It is for an ajax > > service that grabs the XML. > > > > If you use this, expand on it. If you expand on it, post it back on > > here. There are somethings I haven’t gotten to yet. The usage of the > > weather codes needs to get better too. > > Hi Chris, > is there something wrong with the decoded data? > > * * * > > require ‘open-uri’ > > ## url = ‘ftp://weather.noaa.gov/data/observations/metar/decoded/KLGA.TXT’ open(url) do |f| weather = f.read.to\_a.map {|line| line.strip.split(’:’)} label = weather.shift.first.split(’,’).first date = weather.shift.first puts %Q[] weather.each do |w| key = w.first.tr(’()’, ’ ‘).delete(’ ') puts %Q[\<#{key}\>#{w[1].strip}\] end puts ‘’ end > > ## output: > > ## from the NW (320 degrees) at 9 MPH (8 KT) 10 mile(s) partly cloudy 75.0 F (23.9 C) 35.1 F (1.7 C) 23% … > > cheers > > Simon