Module: SpatialFeatures::ClassMethods

Defined in:
lib/spatial_features/has_spatial_features.rb

Instance Method Summary collapse

Instance Method Details

#area_in_square_meters ⇒ Object 



98
99
100
 
# File 'lib/spatial_features/has_spatial_features.rb', line 98

def area_in_square_meters
  features.area_in_square_meters
end

#covering(other) ⇒ Object 



49
50
51
52
53
54
 
# File 'lib/spatial_features/has_spatial_features.rb', line 49

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 



68
69
70
71
72
73
74
 
# File 'lib/spatial_features/has_spatial_features.rb', line 68

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



28
29
30
31
 
# File 'lib/spatial_features/has_spatial_features.rb', line 28

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) 


94
95
96
 
# File 'lib/spatial_features/has_spatial_features.rb', line 94

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) 


89
90
91
 
# File 'lib/spatial_features/has_spatial_features.rb', line 89

def has_spatial_features_hash?
  column_names.include? 'features_hash'
end

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



33
34
35
 
# File 'lib/spatial_features/has_spatial_features.rb', line 33

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



78
79
80
 
# File 'lib/spatial_features/has_spatial_features.rb', line 78

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 



60
61
62
 
# File 'lib/spatial_features/has_spatial_features.rb', line 60

def lines
  features.lines
end

#other_features_union(other) ⇒ Object 



82
83
84
85
86
 
# File 'lib/spatial_features/has_spatial_features.rb', line 82

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 



64
65
66
 
# File 'lib/spatial_features/has_spatial_features.rb', line 64

def points
  features.points
end

#polygons ⇒ Object 



56
57
58
 
# File 'lib/spatial_features/has_spatial_features.rb', line 56

def polygons
  features.polygons
end

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



37
38
39
40
41
42
43
44
45
46
47
 
# File 'lib/spatial_features/has_spatial_features.rb', line 37

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