Makes things from code and/or wood, rides bikes and waves. Fascinated by machines since the Commodore 64 days. Trying to teach my small humans to ask great questions.
![# Returns locations within radius_km kilometers of this location
# @param radius_km [Float] radius in kilometers
# @return [ActiveRecord::Relation] locations within the radius
def nearby(radius_km)
return Location.none if lat.nil? || lng.nil?
# Earth's radius in kilometers
earth_radius = 6371.0
Location
.where.not(lat: nil)
.where.not(lng: nil)
.where(
"(#{earth_radius} * 2 * ASIN(SQRT(" \
"POWER(SIN((#{lat} * PI() / 180 - lat * PI() / 180) / 2), 2) + " \
"COS(#{lat} * PI() / 180) * COS(lat * PI() / 180) * " \
"POWER(SIN((#{lng} * PI() / 180 - lng * PI() / 180) / 2), 2)" \
"))) <= ?", radius_km)
end](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:4nky5hsvuus2fugl7ldaq57x/bafkreifje2joi5dcqynrnahegkcfgtkbt7hyv25pgnmdpuamcfstm3fjle)
Makes things from code and/or wood, rides bikes and waves. Fascinated by machines since the Commodore 64 days. Trying to teach my small humans to ask great questions.