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 62

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

.bounds ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 220

def self.bounds
  values = pluck('MAX(north) AS north, MAX(east) AS east, MIN(south) AS south, MIN(west) AS west').first
  [:north, :east, :south, :west].zip(values).to_h.with_indifferent_access.transform_values!(&:to_f) if values&.compact.present?
end

.cache_derivatives(options = {}) ⇒ Object 



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

def self.cache_derivatives(options = {})
  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.fetch(:lowres_simplification, lowres_simplification)}),\n    tilegeom     = ST_Transform(geom, 3857)\n  SQL\n\n  invalid('geom_lowres').update_all <<-SQL.squish\n    geom_lowres  = ST_Buffer(geom_lowres, 0)\n  SQL\nend\n".squish

.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, features_only: false, include_record_identifiers: false) ⇒ Object

default srid is 4326 so output is Google Maps compatible



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# File 'app/models/abstract_feature.rb', line 172

def self.geojson(lowres: false, precision: 6, properties: true, srid: 4326, centroids: false, features_only: false, include_record_identifiers: 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 = []

  if include_record_identifiers
    properties_sql << "hstore(ARRAY['feature_name', name::varchar, 'feature_id', id::varchar, 'spatial_model_type', spatial_model_type::varchar, 'spatial_model_id', spatial_model_id::varchar])"
  end

  if properties
    properties_sql << "metadata"
  end

  if properties.is_a?(Hash)
    properties_sql << "      hstore(ARRAY[\#{properties.flatten.map {|e| \"'\#{e.to_s}'\" }.join(',')}])\n    SQL\n  end\n\n  properties_sql = <<~SQL if properties_sql.present?\n    , 'properties', hstore_to_json(\#{properties_sql.join(' || ')})\n  SQL\n\n  sql = <<~SQL\n    json_agg(\n      json_build_object(\n        'type', 'Feature',\n        'geometry', ST_AsGeoJSON(\#{column}, \#{precision})::json\n        \#{properties_sql}\n      )\n    )\n  SQL\n\n  sql = <<~SQL unless features_only\n    json_build_object(\n      'type', 'FeatureCollection',\n      'features', \#{sql}\n    )\n  SQL\n  SpatialFeatures::Utils.select_db_value(all.select(sql))\nend\n"

.intersecting(other) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 77

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

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



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# File 'app/models/abstract_feature.rb', line 85

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

.mvt(*args, **kwargs) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 135

def self.mvt(*args, **kwargs)
  select_sql = mvt_sql(*args, **kwargs)

  # Result is a hex string representing the desired binary output so we need to convert it to binary
  result = SpatialFeatures::Utils.select_db_value(select_sql)
  result.remove!(/^\\x/)
  result = result.scan(/../).map(&:hex).pack('c*')

  return result
end

.mvt_sql(tile_x, tile_y, zoom, properties: true, centroids: false, metadata: {}, scope: nil) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 146

def self.mvt_sql(tile_x, tile_y, zoom, properties: true, centroids: false, metadata: {}, scope: nil)
  if centroids
    column = 'ST_Transform(centroid::geometry, 3857)' # MVT works in SRID 3857
  else
    column = 'tilegeom'
  end

  subquery = select(:id)
              .select("ST_AsMVTGeom(#{column}, ST_TileEnvelope(#{zoom}, #{tile_x}, #{tile_y}), extent => 4096, buffer => 64) AS geom")
              .where("#{column} && ST_TileEnvelope(#{zoom}, #{tile_x}, #{tile_y}, margin => (64.0 / 4096))")
              .order(:id)

  # Merge additional scopes in to allow joins and other columns to be included in the feature output
  subquery = subquery.merge(scope) unless scope.nil?

  # Add metadata
  metadata.each do |column, value|
    subquery = subquery.select("#{value} AS #{column}")
  end

  select_sql = "    SELECT ST_AsMVT(mvtgeom.*, 'default', 4096, 'geom', 'id') AS mvt\n    FROM (\#{subquery.to_sql}) mvtgeom\n  SQL\nend\n"

.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 67

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 89

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 81

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).distinct
end

.within_distance_of_point(lat, lng, distance_in_meters, geom = 'geom_lowres') ⇒ Object 



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

def self.within_distance_of_point(lat, lng, distance_in_meters, geom = 'geom_lowres')
  point_sql =
    case geom.to_s
    when 'geog' then 'ST_Point(:lng, :lat)'
    else "ST_Transform(ST_SetSRID(ST_Point(:lng, :lat), 4326), #{detect_srid(geom)})"
    end

  where("ST_DWithin(features.#{geom}, #{point_sql}, :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 102

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

#bounds ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 225

def bounds
  slice(:north, :east, :south, :west).with_indifferent_access.transform_values!(&:to_f)
end

#cache_derivatives(*args) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 229

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 93

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

#geojson(*args) ⇒ Object 



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# File 'app/models/abstract_feature.rb', line 238

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 233

def kml(options = {})
  column = options[:lowres] ? 'geom_lowres' : 'geog'
  return SpatialFeatures::Utils.select_db_value(self.class.where(:id => id).select("ST_AsKML(#{column}, 6)"))
end

#make_valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/abstract_feature.rb', line 242

def make_valid?
  @make_valid
end