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

Parameters:

  • value —

    the value to set the attribute make_valid to.



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

def make_valid=(value)
  @make_valid = value
end

Class Method Details

.area_in_square_meters ⇒ Object 



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

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 



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# File 'app/models/feature.rb', line 68

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\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  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

.detect_srid(column_name) ⇒ Object 



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# File 'app/models/feature.rb', line 126

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 



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# File 'app/models/feature.rb', line 47

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 



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# File 'app/models/feature.rb', line 51

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 



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# File 'app/models/feature.rb', line 130

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

.lines ⇒ Object 



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

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

.points ⇒ Object 



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

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

.polygons ⇒ Object 



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# File 'app/models/feature.rb', line 23

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

.total_intersection_area_in_square_meters(other_features) ⇒ Object 



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

def self.total_intersection_area_in_square_meters(other_features)
  unscoped
    .from("(#{select("ST_Union(geom) AS geom").to_sql}) features, (#{other_features.to_sql}) other_features")
    .pluck('ST_Area(ST_UNION(ST_Intersection(features.geom, other_features.geom)))')
    .first.to_f
end

.valid ⇒ Object 



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

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

.with_metadata(k, v) ⇒ Object 



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

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 



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# File 'app/models/feature.rb', line 100

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

#envelope(buffer_in_meters = 0) ⇒ Object 



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

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 



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# File 'app/models/feature.rb', line 96

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

#kml(options = {}) ⇒ Object 



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# File 'app/models/feature.rb', line 104

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

#make_valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/feature.rb', line 110

def make_valid?
  @make_valid
end