gis = require('gis')
 gis.install()
 -- https://source.opennews.org/en-US/learning/choosing-right-map-projection/
 wgs84 = 4326 -- WGS84 World-wide Projection (Lon/Lat)
 nationalmap = 2163 -- US National Atlas Equal Area projection (meters)
 calif5 = 2770 -- California zone 5 projection (meters)
 nevada = gis.Polygon({{
     {-120.000000, 42.000000};
     {-114.000000, 42.000000};
     {-114.000000, 34.687427};
     {-120.000000, 39.000000};
     {-120.000000, 42.000000};
 }}, wgs84)

 nevada:wkt()
 => "POLYGON ((-120 42, -114 42, -114 34.687427, -120 39, -120 42))"

 lasvegas = gis.Point({-115.136389, 36.175}, wgs84)
 losangeles = gis.Point({-118.25, 34.05}, wgs84)

 nevada:contains(lasvegas)
 => true
 nevada:contains(losangeles)
 => false
 line = gis.LineString({lasvegas, losangeles}, wgs84)
 line:transform(calif5):length()
 => 368.94277529796 - km
 nevada:transform(nationalmap):area() * 1e-6
 => 293496.74070953 -- km^2

 #!/usr/bin/env tarantool

 box.cfg({logger = 'tarantool.log'})
 local httpc = require('http.client')
 local json = require('json')
 local yaml = require('yaml')
 local gis = require('gis')
 gis.install() -- creates system tables in Tarantool, e.g. spatial_ref_sys

 local function tocube(coords)
     return gis.Point(coords, 4326):transform(4328) -- lonlat to geocentric (3D)
 end

 box.once("data", function()
     print('Creating spaces...')
     local postoffices = box.schema.space.create("postoffices")
     postoffices:create_index('primary', { type = 'HASH', parts = {1, 'num'}})
     postoffices:create_index('spatial', { type = 'RTREE', parts = {2, 'array'},
         unique = false, dimension = 3})

     print('Downloading source data...')
     local URL = 'http://api.data.mos.ru/v1/datasets/1095/rows'
     local sourcedata = json.decode(httpc.get(URL).body)
     print('Populating database...')
     for _, info in pairs(sourcedata) do
         local postalcode = tonumber(info.Cells.PostalCode)
         local lon = tonumber((info.Cells.X_WGS84:gsub(',', '.')))
         local lat = tonumber((info.Cells.Y_WGS84:gsub(',', '.')))
         local address = info.Cells.Address
         postoffices:replace({postalcode, tocube({lon, lat}):totable(), {lon, lat}, address})
     end
 end)

 local function nearby(coords, count)
     local point = tocube(coords)
     for _, office in box.space.postoffices.index.spatial:pairs(point:totable(),
         { iterator = 'neighbor' }):take(count) do
         print(json.encode({
             PostalCode = office[1];
             Address = office[4];
             Distance = math.ceil(point:distance(tocube(office[3])))
         }))
     end
 end

 nearby({37.479407, 55.862488}, 5)
 --[[
 {"Address":"Фестивальная улица, дом 39","Distance":463,"PostalCode":125195}
 {"Address":"Валдайский проезд, дом 8, строение 2","Distance":764,"PostalCode":125445}
 {"Address":"Петрозаводская улица, дом 9, корпус 2","Distance":985,"PostalCode":125502}
 {"Address":"улица Ляпидевского, дом 14","Distance":1154,"PostalCode":125581}
 {"Address":"Ленинградское шоссе, дом 84, корпус 2","Distance":1289,"PostalCode":125565}
 --]]

 nearby({37.537407, 55.796782}, 5)
 --[[
 {"Address":"Ленинский проспект, дом 41","Distance":150,"PostalCode":119334}
 {"Address":"Ленинградский проспект, дом 56","Distance":168,"PostalCode":125167}
 {"Address":"улица Черняховского, дом 6","Distance":696,"PostalCode":125319}
 {"Address":"улица Усиевича, дом 16","Distance":1232,"PostalCode":125190}
 {"Address":"Ленинградский проспект, дом 69","Distance":1357,"PostalCode":125057}
 --]]