Class: MODEL_NAME

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/generators/census_shapes/setup/templates/models/shape.rb

Direct Known Subclasses

Aiannh, Aits, Anrc, BG, Block, Cbsa, Cd, County, Cousub, Csa, Elsd, Metdiv, Place, Scsd, Sldl, Sldu, State, Submcd, Tract, Unsd, Vtd, Zcta5

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.available_shapes ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 132

def self.available_shapes
  return @available_shapes if @available_shapes
  @available_shapes = CENSUS_SHAPES
  available_types = MODEL_NAME.unscoped.select("DISTINCT(type)").map{|k,v| k['type'].upcase}
  @available_shapes.each do |k,v|
    @available_shapes.delete(k) if !available_types.include?(k)
  end
  return @available_shapes
end

.bbox(z, x, y) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 26

def self.bbox(z,x,y)
  return false if z.nil? || x.nil? || y.nil?
  nw=coordinateLocation(z.to_i,x.to_i,y.to_i)
  se=coordinateLocation(z.to_i,x.to_i+1,y.to_i+1)
  return "#{nw[:lng]},#{se[:lat]},#{se[:lng]},#{nw[:lat]}"
end

.coordinateLocation(z, x, y) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 33

def self.coordinateLocation(z,x,y)
  k = 45 / 2 ** (z - 3.001)
  return {:lng=> (k * x - 180).to_i,:lat=> y2lat(180 - k * y)}
end

.features(options = {}) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 43

def self.features(options={})
  features = []; i =1; 
  options[:detail]=0.01 if options[:detail].nil?
  model = options[:type].capitalize.constantize
  if !options[:detail].nil?
    geos = model.select("name10, geoid10, ST_AsGeoJson(ST_SimplifyPreserveTopology(geom,#{options[:detail]})) AS geojson");
  else
    geos = model.select("name10, geoid10, ST_AsGeoJson(geom) As geojson, geom, ST_Area(geom) AS area, ST_IsValid(geom) AS isvalid");
  end
  if(options[:bbox])
    b = options[:bbox].split(",")
    ids = model.select("geoid10").where("ST_Contains(ST_AsText(ST_Envelope('LINESTRING(#{b[0]} #{b[1]},#{b[2]} #{b[3]})'::geometry)), ST_AsText(latlng))").map{|id| id['geoid10']}
    if options[:grid]
      geobox = model.select("ST_AsGeoJson(ST_Envelope('LINESTRING(#{b[0]} #{b[1]},#{b[2]} #{b[3]})'::geometry)) AS geojson").first
      features <<  {:type => "Feature", :geometry=> JSON.parse(geobox['geojson']), :properties => {:id=> "1", :name => "Box", :class=> 'box'}} 
    end
    if ids.empty?
      geos = []
    else
      geos = geos.where(:geoid10 => ids)
    end
  end
  if(options[:id])
     geos = geos.where(:geoid10=>options[:id].split(","))
  end
  for g in geos
    if g['isvalid'] != "t" && options[:fix_geom]
      new_g = g.fix_geometry
      msg = "Geometry invalid. Rebuilding. Original = #{g['isvalid'] == "t"}, Rebuilt Geometry = #{new_g['isvalid'] == "t"}, Old area (#{g['area']}) == New area (#{new_g['area']})"
      features <<  {:type => "Feature", :geometry=> JSON.parse(new_g['geojson']), :properties => {:id=> g.geoid10, :name => g.name10 }} 
    else
      features <<  {:type => "Feature", :geometry=> JSON.parse(g['geojson']), :properties => {:id=> g.geoid10, :name => g.name10 }} 
    end
    i=i+1
  end
  return features
end

.merge(polygons) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 121

def self.merge(polygons)
  if polygons.count == 1
    return polygons[0]
  else
    array = polygons.map { |p| "ST_GeomFromText('#{p}')" }
    geo = ActiveRecord::Base.connection.execute("SELECT ST_Collect(ARRAY[#{array.join(',')}]) AS geo").first['geo']
    sql = "SELECT '#{geo}' AS geo, ST_AsGeoJson('#{geo}') AS geojson, ST_Area('#{geo}') AS area, ST_IsValid('#{geo}') AS isvalid;"
    return ActiveRecord::Base.connection.execute(sql).first
  end
end

.rebuild(polygons) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 106

def self.rebuild(polygons)
  polygons = MODEL_NAME.sort(polygons)
  polygons.reverse.each do |p1|
    polygons.each do |p2|
       if p1 != p2 && ActiveRecord::Base.connection.execute("SELECT ST_Contains('#{p1}', '#{p2}') AS contains").first['contains'] == "t"
        temp = ActiveRecord::Base.connection.execute("SELECT ST_AsText(ST_Difference('#{p1}', '#{p2}')) AS union")
        polygons.delete(p1); polygons.delete(p2)
        polygons << temp.first['union']
      end
    end
  end
  polygons = MODEL_NAME.merge(polygons)
  return polygons
end

.sort(polygons) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 99

def self.sort(polygons)
  return polygons.map{|p| 
    pp = ActiveRecord::Base.connection.execute("SELECT ST_Area('#{p}'), ST_AsText('#{p}') AS geo").first
    [pp['st_area'].to_f, pp['geo'] ]}.sort {|a, b| a[0] <=> b[0]}.reverse.map{|p| p[1]
  }
end

.y2lat(y) ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 38

def self.y2lat(y)
  return (360 / Math::PI * Math.atan(Math.exp(y * Math::PI / 180)) -90).round(2)
end

Instance Method Details

#buffer ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 91

def buffer
  return self.class.name.constantize.select("geoid10, ST_Buffer(geom,.000001) AS geo, ST_AsGeoJson(ST_Buffer(geom,.000001)) AS geojson, ST_IsValid(ST_Buffer(geom,.000001)) AS isvalid, ST_Area(ST_Buffer(geom,.000001)) AS area").where(:geoid10 => self.geoid10).first
end

#fix_geometry ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 81

def fix_geometry
  return self if self['isvalid'] == "t"
  rebuilt_g = MODEL_NAME.rebuild(self.polygons)
  return rebuilt_g if rebuilt_g['isvalid'] == "t"
  buffer_g = self.buffer
  return buffer_g if buffer_g['isvalid'] == "t"
  puts "ERROR GEOMETRY NOT FIXED"
  return false
end

#polygons ⇒ Object 



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# File 'lib/generators/census_shapes/setup/templates/models/shape.rb', line 95

def polygons
   return self.class.name.constantize.select("ST_AsText((ST_DumpRings(((ST_Dump(geom)).geom))).geom) AS g").where(:geoid10 => self.geoid10).map{|p| p['g'] }
end