Class: Feature

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

Constant Summary collapse

FEATURE_TYPES = 
%w(polygon point line)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#make_valid=(value) ⇒ Object

Sets the attribute make_valid



4
5
6
 
# File 'app/models/feature.rb', line 4

def make_valid=(value)
  @make_valid = value
end

Class Method Details

.area_in_square_meters(geom = 'geom_lowres') ⇒ Object 



39
40
41
42
 
# File 'app/models/feature.rb', line 39

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

.cache_derivatives(options = {}) ⇒ Object 



75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
 
# File 'app/models/feature.rb', line 75

def self.cache_derivatives(options = {})
  options.reverse_merge! :lowres_simplification => 2, :lowres_precision => 5

  update_all "    geom         = ST_Transform(geog::geometry, \#{detect_srid('geom')}),\n    north        = ST_YMax(geog::geometry),\n    east         = ST_XMax(geog::geometry),\n    south        = ST_YMin(geog::geometry),\n    west         = ST_XMin(geog::geometry),\n    area         = ST_Area(geog),\n    centroid     = ST_PointOnSurface(geog::geometry)\n  SQL\n\n  invalid('geom').update_all <<-SQL.squish\n    geom         = ST_Buffer(geom, 0)\n  SQL\n\n  update_all <<-SQL.squish\n    geom_lowres  = ST_SimplifyPreserveTopology(geom, \#{options[:lowres_simplification]})\n  SQL\n\n  invalid('geom_lowres').update_all <<-SQL.squish\n    geom_lowres  = ST_Buffer(geom_lowres, 0)\n  SQL\n\n  update_all <<-SQL.squish\n    kml          = ST_AsKML(geog, 6),\n    kml_lowres   = ST_AsKML(geom_lowres, \#{options[:lowres_precision]}),\n    kml_centroid = ST_AsKML(centroid)\n  SQL\nend\n".squish

.cache_key ⇒ Object 



15
16
17
 
# File 'app/models/feature.rb', line 15

def self.cache_key
  "#{maximum(:id)}-#{count}"
end

.detect_srid(column_name) ⇒ Object 



137
138
139
 
# File 'app/models/feature.rb', line 137

def self.detect_srid(column_name)
  SRID_CACHE[column_name] ||= connection.select_value("SELECT Find_SRID('public', '#{table_name}', '#{column_name}')")
end

.intersecting(other) ⇒ Object 



54
55
56
 
# File 'app/models/feature.rb', line 54

def self.intersecting(other)
  join_other_features(other).where('ST_Intersects(features.geom_lowres, other_features.geom_lowres)').uniq
end

.invalid(column = 'geog::geometry') ⇒ Object 



58
59
60
 
# File 'app/models/feature.rb', line 58

def self.invalid(column = 'geog::geometry')
  select("features.*, ST_IsValidReason(#{column}) AS invalid_geometry_message").where.not("ST_IsValid(#{column})")
end

.join_other_features(other) ⇒ Object 



141
142
143
 
# File 'app/models/feature.rb', line 141

def self.join_other_features(other)
  joins('INNER JOIN features AS other_features ON true').where(:other_features => {:id => other})
end

.lines ⇒ Object 



31
32
33
 
# File 'app/models/feature.rb', line 31

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

.points ⇒ Object 



35
36
37
 
# File 'app/models/feature.rb', line 35

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

.polygons ⇒ Object 



27
28
29
 
# File 'app/models/feature.rb', line 27

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

.total_intersection_area_in_square_meters(other_features, geom = 'geom_lowres') ⇒ Object 



44
45
46
47
48
49
50
51
52
 
# File 'app/models/feature.rb', line 44

def self.total_intersection_area_in_square_meters(other_features, geom = 'geom_lowres')
  scope = unscope(:select).select("ST_Union(#{geom}) AS geom").polygons
  other_scope = other_features.polygons

  query = unscoped.select('ST_Area(ST_Intersection(ST_Union(features.geom), ST_Union(other_features.geom)))')
                  .from(scope, "features")
                  .joins("INNER JOIN (#{other_scope.to_sql}) AS other_features ON ST_Intersects(features.geom, other_features.geom)")
  return connection.select_value(query).to_f
end

.valid ⇒ Object 



62
63
64
 
# File 'app/models/feature.rb', line 62

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

.with_metadata(k, v) ⇒ Object 



19
20
21
22
23
24
25
 
# File 'app/models/feature.rb', line 19

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 



111
112
113
 
# File 'app/models/feature.rb', line 111

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

#envelope(buffer_in_meters = 0) ⇒ Object 



66
67
68
69
70
71
72
73
 
# File 'app/models/feature.rb', line 66

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

#feature_bounds ⇒ Object 



107
108
109
 
# File 'app/models/feature.rb', line 107

def feature_bounds
  {n: north, e: east, s: south, w: west}
end

#kml(options = {}) ⇒ Object 



115
116
117
118
119
 
# File 'app/models/feature.rb', line 115

def kml(options = {})
  geometry = options[:lowres] ? kml_lowres : super()
  geometry = "<MultiGeometry>#{geometry}#{kml_centroid}</MultiGeometry>" if options[:centroid]
  return geometry
end

#make_valid? ⇒ Boolean 



121
122
123
 
# File 'app/models/feature.rb', line 121

def make_valid?
  @make_valid
end