GOALS

• add a location to your models (latitude/longitude)
• find other models in a certain radius
• find other models on the same map (giving map size in pixels and zoom level)
• prevent assignment of a default location (value your map script uses as default/starting point)
• complete test coverage

INSTALL

script/plugin install git://github.com/ptb/geokit.git
script/plugin install git://github.com/grosser/has_a_location.git

Table with (see: MIGRATION):

lat
lng

Model:

User < ActiveRecord::Base
  has_a_location :default_location_lat=>10.10,:default_location_lng=>20.20
end

USAGE

• user.location = [12.2332,323.2323] [latitude,longitude]
• show_map if user.location
• user.in_radius(500) => users in 500 miles distance
• User.on_map([11.12343,34,183323],[640,480],5) => all users visible on a 640x480 map zoom-level 5, with center 11.12343,34,183323
• user.surrounding_on_map([640,480],5) => other users visible on this map

OPTIONS

Legend: options key => default [recommended]
:default_location_lng => 0 [your default map longitude]
:default_location_lat => 0 [your default map latitude]
:default_units => :miles [:kms]
:default_formula => :sphere [:flat]
:lat_column_name=>:lat [:location_latitude]
:lng_column_name=>:lng [:location_longitude]
:distance_column_name=>:distance [:distance]

TODO

• latitude calculation is theoretically (wrong theory?) wrong put works practically...

AUTHOR

Michael Grosser
grosser dot michael ät gmail dot com