Module: SpatialFeatures::ClassMethods

Defined in:
lib/spatial_features/has_spatial_features.rb

Instance Method Summary collapse

Instance Method Details

#acts_like_spatial_features? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spatial_features/has_spatial_features.rb', line 35

def acts_like_spatial_features?
  true
end

#area_in_square_meters ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 112

def area_in_square_meters
  features.area_in_square_meters
end

#covering(other) ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 63

def covering(other)
  scope = joins_features_for(other).select("#{table_name}.*").group("#{table_name}.#{primary_key}")
  scope = scope.where('ST_Covers(features.geom, features_for_other.geom)')

  return scope
end

#features ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 82

def features
  if all == unscoped
    Feature.where(:spatial_model_type => self)
  else
    Feature.where(:spatial_model_type => self, :spatial_model_id => all.unscope(:select))
  end
end

#features_cache_key ⇒ Object

Add methods to generate cache keys for a record or all records of this class NOTE: features are never updated, only deleted and created, therefore we can tell if they have changed by finding the maximum id and count instead of needing timestamps



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# File 'lib/spatial_features/has_spatial_features.rb', line 42

def features_cache_key
  # Do two separate queries because it is much faster for some reason
  "#{name}/#{features.maximum(:id)}-#{features.count}"
end

#has_features_area? ⇒ Boolean

Returns true if the model stores a cache of the features area

Returns:

  • (Boolean) 


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# File 'lib/spatial_features/has_spatial_features.rb', line 108

def has_features_area?
  column_names.include? 'features_area'
end

#has_spatial_features_hash? ⇒ Boolean

Returns true if the model stores a hash of the features so we don’t need to process the features if they haven’t changed

Returns:

  • (Boolean) 


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# File 'lib/spatial_features/has_spatial_features.rb', line 103

def has_spatial_features_hash?
  column_names.include? 'features_hash'
end

#intersecting(other, options = {}) ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 47

def intersecting(other, options = {})
  within_buffer(other, 0, options)
end

#joins_features_for(other, table_alias = 'features_for') ⇒ Object

Returns a scope that includes the features for this record as the table_alias and the features for other as #table_alias_other Can be used to perform spatial calculations on the relationship between the two sets of features



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# File 'lib/spatial_features/has_spatial_features.rb', line 92

def joins_features_for(other, table_alias = 'features_for')
  joins(:features).joins(%Q(INNER JOIN (#{other_features_union(other).to_sql}) AS "#{table_alias}_other" ON true))
end

#lines ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 74

def lines
  features.lines
end

#other_features_union(other) ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 96

def other_features_union(other)
  scope = Feature.select('ST_Union(geom) AS geom').where(:spatial_model_type => class_for(other))
  scope = scope.where(:spatial_model_id => other) unless class_for(other) == other
  return scope
end

#points ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 78

def points
  features.points
end

#polygons ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 70

def polygons
  features.polygons
end

#within_buffer(other, buffer_in_meters = 0, options = {}) ⇒ Object 



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# File 'lib/spatial_features/has_spatial_features.rb', line 51

def within_buffer(other, buffer_in_meters = 0, options = {})
  return none if other.is_a?(ActiveRecord::Base) && other.new_record?

  # Cache only works on single records, not scopes.
  # This is because the cached intersection_area doesn't account for overlaps between the features in the scope.
  if options[:cache] != false && other.is_a?(ActiveRecord::Base)
    cached_within_buffer_scope(other, buffer_in_meters, options)
  else
    uncached_within_buffer_scope(other, buffer_in_meters, options)
  end
end