disjoint thoughts

I wrote a little Ruby script to parse some hot spring data and throw it into a kml file for display in google maps or google earth (here’s the results). It doesn’t do anything too complex, but it makes for a decent example of using hpricot to parse html and rexml to generate kml. Here’s the source if anyone would like to take a look:

#written by Benjamin Smith
#www.disjointthoughts.com
#benjamin.lee.smith@gmail.com

require 'hpricot'
require 'open-uri'
require 'rexml/document'
require 'erb'

#arg: url to parse from http://www.hotspringsenthusiast.com/TextLinks.asp
#doesnt work for arkansas, georgia, new york, north carolina, south dakota, virgina
url = ARGV[0]

#parse name of state out of url
state = url[url.index('.com')+5..url.length-5]

#grab the html
doc = Hpricot(open(url))

#create xml for the kml file
xml = REXML::Document.new
kml = xml.add_element 'kml', {'xmlns' => 'http://earth.google.com/kml/2.1'}
kml_doc = kml.add_element 'Document'

#add the name of the state to the xml
(kml_doc.add_element 'name').text = "#{state} Hot Springs"

#add reference to me
(kml_doc.add_element 'description').text = 'created by Benjamin Smith http://www.disjointthoughts.com'
doc_folder = kml_doc.add_element 'Folder'

#add reference to the data source
(doc_folder.add_element 'name').text = 'http://www.hotspringsenthusiast.com/'
(doc_folder.add_element 'description').text = "data source #{url}"

#iterate over the rows in the table
doc.search('//tr').each do |tr|
  tds = tr.search('//td')
  if tds.first.inner_html != 'STATE'
    link = tds[3].search('//a').to_s
    lat = link[link.index('lat=')+4..link.index('&',link.index('lat='))-1]
    lon = link[link.index('lon=')+4..link.index('"',link.index('lon='))-1].gsub('E','')
    topo = link[link.index('href="')+6..link.index('"',link.index('href="')+7)-1] 

    placemark = doc_folder.add_element 'Placemark'
    (placemark.add_element('name')).text = tds[3].search('//a').inner_html.to_s.gsub("\r\n",'').squeeze.downcase
    (placemark.add_element('description')).text = REXML::CData.new('Temperature: '+tds[4].inner_html+'F/'+tds[5].inner_html+'C<br/><a href="'+topo+'">Topo')
    point = placemark.add_element 'Point'
    (point.add_element 'coordinates').text = "#{lon.to_s},#{lat.to_s}"
  end
end

f = File.new("#{state.downcase}.kml",'w')
f.write(''+"\n")
xml.write(f,4)
f.close

#create html file to display kml in google map
erb = ERB.new(File.read('template_hot_springs.erb'))
f = File.new("#{state.downcase}_hot_springs.html",'w')
f.write(erb.result(binding))
f.close

If you’d like to run it on your own, you can download it here. You’ll also need this template file and this css file.

Here’s a google map I made of Arizona’s hot springs. I used a little Ruby script with Hpricot to parse the data from the Hot Springs Enthusiast website (I later realized that the original data comes from the National Geophysical Data Center).

Click here for a bigger version of this map.