class Geokit::Adapters::SQLite

Public Class Methods

add_math(name) click to toggle source
# File lib/geokit-rails/adapters/sqlite.rb, line 11
def self.add_math(name)
  add_numeric name do |*n|
    Math.send name, *n
  end
end
add_numeric(name) { |*args| ... } click to toggle source
# File lib/geokit-rails/adapters/sqlite.rb, line 5
def self.add_numeric(name) 
  @@connection.create_function name, 1, SQLite3::Constants::TextRep::ANY do |func, *args|
    func.result = yield(*args)
  end
end
load(klass) click to toggle source
# File lib/geokit-rails/adapters/sqlite.rb, line 18
def load(klass)
  @@connection = klass.connection.raw_connection
  # Define the functions needed
  add_math 'sqrt'
  add_math 'cos'
  add_math 'acos'
  add_math 'sin'

  add_numeric('pow') { |n, m| n**m }
  add_numeric('radians') { |n| n * Math::PI / 180 }
  add_numeric('least') { |*args| args.min }
end

Public Instance Methods

flat_distance_sql(origin, lat_degree_units, lng_degree_units) click to toggle source
# File lib/geokit-rails/adapters/sqlite.rb, line 42
def flat_distance_sql(origin, lat_degree_units, lng_degree_units)
  %|
    (CASE WHEN #{qualified_lat_column_name} IS NULL OR #{qualified_lng_column_name} IS NULL THEN NULL ELSE
    SQRT(POW(#{lat_degree_units}*(#{origin.lat}-#{qualified_lat_column_name}),2)+
    POW(#{lng_degree_units}*(#{origin.lng}-#{qualified_lng_column_name}),2))
    END)
   |
end
sphere_distance_sql(lat, lng, multiplier) click to toggle source
# File lib/geokit-rails/adapters/sqlite.rb, line 32
def sphere_distance_sql(lat, lng, multiplier)
  %|
    (CASE WHEN #{qualified_lat_column_name} IS NULL OR #{qualified_lng_column_name} IS NULL THEN NULL ELSE
    (ACOS(least(1,COS(#{lat})*COS(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*COS(RADIANS(#{qualified_lng_column_name}))+
    COS(#{lat})*SIN(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*SIN(RADIANS(#{qualified_lng_column_name}))+
    SIN(#{lat})*SIN(RADIANS(#{qualified_lat_column_name}))))*#{multiplier})
    END)
   |
end