Class: AbstractFeature

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

Direct Known Subclasses

AggregateFeature, Feature

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/abstract_feature.rb', line 12

def make_valid=(value)
  @make_valid = value
end

Class Method Details

.area_in_square_meters(geom = 'geom_lowres') ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 56

def self.area_in_square_meters(geom = 'geom_lowres')
  current_scope = all.polygons
  unscoped { SpatialFeatures::Utils.select_db_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/abstract_feature.rb', line 104

def self.cache_derivatives(options = {})
  update_all <<-SQL.squish
    geom         = ST_Transform(geog::geometry, #{detect_srid('geom')}),
    north        = ST_YMax(geog::geometry),
    east         = ST_XMax(geog::geometry),
    south        = ST_YMin(geog::geometry),
    west         = ST_XMin(geog::geometry),
    area         = ST_Area(geog),
    centroid     = ST_PointOnSurface(geog::geometry)
  SQL

  invalid('geom').update_all <<-SQL.squish
    geom         = ST_Buffer(geom, 0)
  SQL

  update_all <<-SQL.squish
    geom_lowres  = ST_SimplifyPreserveTopology(geom, #{options.fetch(:lowres_simplification, lowres_simplification)})
  SQL

  invalid('geom_lowres').update_all <<-SQL.squish
    geom_lowres  = ST_Buffer(geom_lowres, 0)
  SQL
end

.cache_key ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 28

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

.collection_cache_key(_collection, _timestamp_column) ⇒ Object

for Rails >= 5 ActiveRecord collections we override the collection_cache_key to prevent Rails doing its default query on updated_at



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# File 'app/models/abstract_feature.rb', line 24

def self.collection_cache_key(_collection, _timestamp_column)
  self.cache_key
end

.geojson(lowres: false, precision: 6, properties: true, srid: 4326, centroids: false) ⇒ Object

default srid is 4326 so output is Google Maps compatible



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# File 'app/models/abstract_feature.rb', line 128

def self.geojson(lowres: false, precision: 6, properties: true, srid: 4326, centroids: false) # default srid is 4326 so output is Google Maps compatible
  if centroids
    column = 'centroid'
  elsif lowres
    column = "ST_Transform(geom_lowres, #{srid})"
  else
    column = 'geog'
  end

  properties_sql = <<~SQL if properties
    , 'properties', hstore_to_json(metadata)
  SQL

  sql = <<~SQL
    json_build_object(
      'type', 'FeatureCollection',
      'features', json_agg(
        json_build_object(
          'type', 'Feature',
          'geometry', ST_AsGeoJSON(#{column}, #{precision})::json
          #{properties_sql}
        )
      )
    )
  SQL
  SpatialFeatures::Utils.select_db_value(all.select(sql))
end

.intersecting(other) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 71

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/abstract_feature.rb', line 79

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

.lines ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 44

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

.points ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 48

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

.polygons ⇒ Object 



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

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

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



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# File 'app/models/abstract_feature.rb', line 61

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 = base_class.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 SpatialFeatures::Utils.select_db_value(query).to_f
end

.valid ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 83

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

.with_metadata(k, v) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 32

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

.within_distance(other, distance_in_meters) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 75

def self.within_distance(other, distance_in_meters)
  join_other_features(other).where('ST_DWithin(features.geom_lowres, other_features.geom_lowres, ?)', distance_in_meters).uniq
end

.within_distance_of_point(lat, lng, distance_in_meters) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 52

def self.within_distance_of_point(lat, lng, distance_in_meters)
  where("ST_DWithin(features.geog, ST_Point(:lng, :lat), :distance)", :lat => lat, :lng => lng, :distance => distance_in_meters)
end

.without_caching_derivatives(&block) ⇒ Object 



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

def self.without_caching_derivatives(&block)
  old = automatically_cache_derivatives
  self.automatically_cache_derivatives = false
  block.call
ensure
  self.automatically_cache_derivatives = old
end

Instance Method Details

#cache_derivatives(*args) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 160

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

#envelope(buffer_in_meters = 0) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 87

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/abstract_feature.rb', line 156

def feature_bounds
  slice(:north, :east, :south, :west)
end

#geojson(*args) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 170

def geojson(*args)
  self.class.where(id: id).geojson(*args)
end

#kml(options = {}) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 164

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/abstract_feature.rb', line 174

def make_valid?
  @make_valid
end