Class: Feature

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/spatial_features/models/feature.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.area_in_square_meters ⇒ Object 



30
31
32
33
 
# File 'lib/spatial_features/models/feature.rb', line 30

def self.area_in_square_meters
  current_scope = all
  unscoped { connection.select_value(select('ST_Area(ST_Union(geom))').from(current_scope, :features)).to_f }
end

.cache_derivatives(options = {}) ⇒ Object 



60
61
62
63
64
65
66
67
68
69
70
 
# File 'lib/spatial_features/models/feature.rb', line 60

def self.cache_derivatives(options = {})
  options.reverse_merge! :lowres_simplification => 0.00001, :lowres_precision => 5

  update_all("area        = ST_Area(geog),
              geom        = ST_Transform(geog::geometry, 26910),
              geog_lowres = ST_SimplifyPreserveTopology(geog::geometry, #{options[:lowres_simplification]})"
              .squish)
  update_all("kml         = ST_AsKML(features.geog, 6),
              kml_lowres  = ST_AsKML(geog_lowres::geometry, #{options[:lowres_precision]})"
              .squish)
end

.invalid ⇒ Object 



43
44
45
 
# File 'lib/spatial_features/models/feature.rb', line 43

def self.invalid
  select('features.*, ST_IsValidReason(geog::geometry) AS invalid_geometry_message').where.not('ST_IsValid(geog::geometry)')
end

.lines ⇒ Object 



22
23
24
 
# File 'lib/spatial_features/models/feature.rb', line 22

def self.lines
  where(:feature_type => 'line')
end

.points ⇒ Object 



26
27
28
 
# File 'lib/spatial_features/models/feature.rb', line 26

def self.points
  where(:feature_type => 'point')
end

.polygons ⇒ Object 



18
19
20
 
# File 'lib/spatial_features/models/feature.rb', line 18

def self.polygons
  where(:feature_type => 'polygon')
end

.total_intersection_area_in_square_meters(other) ⇒ Object 



35
36
37
38
39
40
41
 
# File 'lib/spatial_features/models/feature.rb', line 35

def self.total_intersection_area_in_square_meters(other)
  scope = join_other_features(other)
    .where('ST_Intersects(features.geog_lowres, other_features.geog_lowres)')
    .select('ST_Area(ST_Intersection(ST_Union(features.geog_lowres::geometry), ST_Union(other_features.geog_lowres::geometry))::geography) AS intersection_area_in_square_meters')

  connection.select_value(scope).to_f
end

.valid ⇒ Object 



47
48
49
 
# File 'lib/spatial_features/models/feature.rb', line 47

def self.valid
  where('ST_IsValid(geog::geometry)')
end

.with_metadata(k, v) ⇒ Object 



10
11
12
13
14
15
16
 
# File 'lib/spatial_features/models/feature.rb', line 10

def self.with_metadata(k, v)
  if k.present? && v.present?
    where('metadata->? = ?', k, v)
  else
    all
  end
end

Instance Method Details

#cache_derivatives(*args) ⇒ Object 



72
73
74
 
# File 'lib/spatial_features/models/feature.rb', line 72

def cache_derivatives(*args)
  self.class.where(:id => self.id).cache_derivatives(*args)
end

#envelope(buffer_in_meters = 0) ⇒ Object 



51
52
53
54
55
56
57
58
 
# File 'lib/spatial_features/models/feature.rb', line 51

def envelope(buffer_in_meters = 0)
  envelope_json = JSON.parse(self.class.select("ST_AsGeoJSON(ST_Envelope(ST_Buffer(features.geog, #{buffer_in_meters})::geometry)) AS result").where(:id => id).first.result)
  envelope_json = envelope_json["coordinates"].first

  raise "Can't calculate envelope for Feature #{self.id}" if envelope_json.blank?

  return envelope_json.values_at(0,2)
end

#kml(options = {}) ⇒ Object 



76
77
78
 
# File 'lib/spatial_features/models/feature.rb', line 76

def kml(options = {})
  options[:lowres] ? kml_lowres : super()
end