Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Geospatial applications on Rails
Search
Sergey Nartimov
June 01, 2013
Programming
8
410
Geospatial applications on Rails
Sergey Nartimov
June 01, 2013
Tweet
Share
More Decks by Sergey Nartimov
See All by Sergey Nartimov
PubSub at Rails
lest
0
120
Rails in production - RubyConfBY 22 Mar 2015
lest
1
150
Sequel - BRUG 21 Feb 2015
lest
0
81
Elixir – Belarus Ruby User Group 25 Jan 2014
lest
3
660
Authentication Security – RUBYSPB
lest
2
170
Design patterns – Belarus Ruby on Rails User Group 23 Feb 2013
lest
8
650
Ruby Stdlib – Minsk.rb October 2012
lest
10
360
Background jobs with realtime results – RailsClub'Moscow 2012
lest
5
210
Other Decks in Programming
See All in Programming
複数アプリケーションを育てていくための共通化戦略
irof
10
4k
Bytecode Manipulation 으로 생산성 높이기
bigstark
2
360
Elixir で IoT 開発、 Nerves なら簡単にできる!?
pojiro
1
150
カクヨムAndroidアプリのリブート
numeroanddev
0
430
すべてのコンテキストを、 ユーザー価値に変える
applism118
1
330
SODA - FACT BOOK
sodainc
1
1.1k
CursorはMCPを使った方が良いぞ
taigakono
0
130
Go1.25からのGOMAXPROCS
kuro_kurorrr
1
770
Rails産でないDBを Railsに引っ越すHACK - Omotesando.rb #110
lnit
1
170
[初登壇@jAZUG]アプリ開発者が気になるGoogleCloud/Azure+wasm/wasi
asaringo
0
130
生成AIコーディングとの向き合い方、AIと共創するという考え方 / How to deal with generative AI coding and the concept of co-creating with AI
seike460
PRO
1
320
GraphRAGの仕組みまるわかり
tosuri13
7
450
Featured
See All Featured
Building Applications with DynamoDB
mza
95
6.5k
Bash Introduction
62gerente
614
210k
Code Reviewing Like a Champion
maltzj
524
40k
Thoughts on Productivity
jonyablonski
69
4.7k
Optimising Largest Contentful Paint
csswizardry
37
3.3k
Building an army of robots
kneath
306
45k
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
danielanewman
228
22k
Typedesign – Prime Four
hannesfritz
42
2.7k
We Have a Design System, Now What?
morganepeng
52
7.6k
A Tale of Four Properties
chriscoyier
159
23k
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
PRO
181
53k
The Language of Interfaces
destraynor
158
25k
Transcript
Geospatial applications on Rails Sergey Nartimov Brainspec https://github.com/lest twitter: @just_lest
About • Rails, Rubinius, Elixir contributor • Software engineer at
Brainspec Sergey Nartimov Brainspec https://github.com/lest twitter: @just_lest
Geospatial data
Geospatial data types • Point • Linestring • Polygon •
Multi... • Geometry collection
Geospatial analysis • Coverage • Intersection • Distance • etc.
Geographic coordinate system
Geographic distance
Map projection
Mercator projection
None
Mercator projection
Mercator projection
Geospatial support
Geospatial support • MySQL • http://dev.mysql.com/doc/refman/5.5/en/ spatial-extensions.html
Geospatial support • MongoDB • http://www.mongodb.org/display/DOCS/ Geospatial+Indexing
Geospatial support • SpatiaLite • http://www.gaia-gis.it/gaia-sins/splite- doxy-4.0.0/index.html
Geospatial support • PostGIS • http://postgis.org/docs/
Rails & PostGIS
• https://github.com/dazuma/activerecord- postgis-adapter • https://github.com/dazuma/rgeo
# config/database.yml adapter: postgis # When postgresql >= 9.1 and
postgis >= 2.0 postgis_extension: true # When postgresql < 9.1 or postgis < 2.0 # e.g. for postgresql 9.1 and postgis 1.5 on ubuntu script_dir: "/usr/share/postgresql/9.1/contrib/postgis-1.5" schema_search_path: public,postgis
create_table :locations do |t| t.point :coords, geographic: true end create_table
:locations do |t| t.string :text t.point :coords, srid: 3785 end add_index :locations, :coords, spatial: true
class Location < ActiveRecord::Base GEOFACTORY = RGeo::Geographic.spherical_factory(srid: 4326) set_rgeo_factory_for_column :coords,
GEOFACTORY end
Points in radius
point = Location::GEOFACTORY.point(27, 53) radius = 50_000 # 50 km
Location.where('st_dwithin(coords, ?, ?)', point, radius) .order('st_distance(coords, ?)', point)
Squeel • https://github.com/ernie/squeel
point = Location::GEOFACTORY.point(27, 53) radius = 50_000 # 50 km
Location.where { st_dwithin(coords, point, radius) } .order { st_distance(coords, point) }
class Location < ActiveRecord::Base GEOFACTORY = RGeo::Geographic.simple_mercator_factory set_rgeo_factory_for_column :coords, GEOFACTORY.projection_factory
end point = Location::GEOFACTORY.point(27, 53) radius = 50_000 / Math.cos(lat * Math::PI / 180.0) Location.where { st_dwithin(coords, point, radius) } .order { st_distance(coords, point) }
Points in bounding box
None
None
sw = Location::GEOFACTORY.point(48.389537, 54.306922) ne = Location::GEOFACTORY.point(48.399643, 54.311216) bbox =
RGeo::Cartesian::BoundingBox.create_from_points(sw, ne) Location.where('coords && ?', bbox)
Clustering • http://pgxn.org/dist/kmeans/ • http://postgis.refractions.net/docs/ ST_SnapToGrid.html
None
Time zones example
• http://efele.net/maps/tz/world/
None
• https://github.com/dazuma/rgeo-shapefile
class CreateTimeZonePolygons < ActiveRecord::Migration def change create_table :time_zone_polygons do |t|
t.string :tzid t.geometry :geometry, geographic: true t.timestamps end add_index :time_zone_polygons, :geometry, spatial: true end end
class TimeZonePolygon < ActiveRecord::Base set_rgeo_factory_for_column :geometry, RGeo::Geographic.spherical_factory(srid: 4326) end
RGeo::Shapefile::Reader.open('tz_world.shp') do |file| file.each do |record| polygon = TimeZonePolygon.new polygon.tzid
= record.attributes['TZID'] polygon.geometry = record.geometry polygon.save! end end
point = TimeZonePolygon::GEOFACTORY.point(27, 53) time_zone = TimeZonePolygon .where { st_covers(geometry,
point) }.first time_zone.tzid # => "Europe/Minsk"
• Further improvements
Thanks <3 Sergey Nartimov Brainspec https://github.com/lest twitter: @just_lest