```ruby
#!/usr/bin/env ruby

require 'rubygems'
require 'bundler/setup'
require 'mormon'
require 'ruby_kml'
require 'pry'

osm_file = 'map.osm'
node_start = '3167844735'
node_end = '2999413127'

loader = Mormon::OSM::Loader.new(osm_file)
router = Mormon::OSM::Router.new(loader)
res = router.find_route(node_start, node_end, :foot)

# Reverse coords since KML uses <lon,lat> instead of <lat,lon>
placemark = KML::Placemark.new(
  geometry: KML::LineString.new(
    tessellate: true,
    coordinates: res[1].map(&:reverse)
  )
)

kml = KMLFile.new
doc = KML::Document.new(
  name: 'ElevationProfiler path',
  features: [placemark]
)
kml.objects << doc
File.open('result.kml', 'w') { |f| f.puts(kml.render) }
```

Raise on no route found
user
```ruby
#!/usr/bin/env ruby

require 'rubygems'
require 'bundler/setup'
require 'mormon'
require 'ruby_kml'
require 'pry'

osm_file = 'map.osm'
node_start = '3167844735'
node_end = '2999412925'

loader = Mormon::OSM::Loader.new(osm_file)
router = Mormon::OSM::Router.new(loader)
res = router.find_route(node_start, node_end, :foot)

raise 'No route found' if res[1].empty?

# Reverse coords since KML uses <lon,lat> instead of <lat,lon>
placemark = KML::Placemark.new(
  geometry: KML::LineString.new(
    tessellate: true,
    coordinates: res[1].map(&:reverse)
  )
)

kml = KMLFile.new
doc = KML::Document.new(
  name: 'ElevationProfiler path',
  features: [placemark]
)
kml.objects << doc
File.open('result.kml', 'w') { |f| f.puts(kml.render) }
```
assistant