Class: GeoRuby::SimpleFeatures::Geometry

Inherits:
Object
  • Object
show all
Defined in:
lib/geo_ruby/simple_features/geometry.rb

Overview

Root of all geometric data classes. Objects of class Geometry should not be instantiated.

Direct Known Subclasses

Circle, GeometryCollection, LineString, Point, Polygon

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(srid = DEFAULT_SRID, with_z = false, with_m = false) ⇒ Geometry


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 18

def initialize(srid = DEFAULT_SRID, with_z = false, with_m = false)
  @srid = srid
  @with_z = with_z
  @with_m = with_m
end

Instance Attribute Details

#sridObject

SRID of the geometry


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 10

def srid
  @srid
end

#with_mObject Also known as: with_m?

Flag indicating if the m ordinate of the geometry is meaningful


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 15

def with_m
  @with_m
end

#with_zObject Also known as: with_z?

Flag indicating if the z ordinate of the geometry is meaningful


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 12

def with_z
  @with_z
end

Class Method Details

.from_ewkb(ewkb) ⇒ Object

Creates a geometry based on a EWKB string. The actual class returned depends of the content of the string passed as argument. Since WKB strings are a subset of EWKB, they are also valid.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 187

def self.from_ewkb(ewkb)
  factory = GeometryFactory.new
  ewkb_parser = EWKBParser.new(factory)
  ewkb_parser.parse(ewkb)
  factory.geometry
end

.from_ewkt(ewkt) ⇒ Object

Creates a geometry based on a EWKT string. Since WKT strings are a subset of EWKT, they are also valid.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 204

def self.from_ewkt(ewkt)
  factory = GeometryFactory.new
  ewkt_parser = EWKTParser.new(factory)
  ewkt_parser.parse(ewkt)
  factory.geometry
end

.from_geojson(geojson, srid = DEFAULT_SRID) ⇒ Object

Some GeoJSON files do not include srid info, so we provide an optional parameter


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 236

def self.from_geojson(geojson, srid = DEFAULT_SRID)
  geojson_parser = GeoJSONParser.new
  geojson_parser.parse(geojson, srid)
  geojson_parser.geometry
end

.from_georss(georss) ⇒ Object

Creates a geometry based on the GeoRSS string given.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 212

def self.from_georss(georss)
  georss_parser = GeorssParser.new
  georss_parser.parse(georss)
  georss_parser.geometry
end

.from_georss_with_tags(georss) ⇒ Object

sends back an array: The first element is the goemetry based on the GeoRSS string passed as argument. The second one is the GeoRSSTags (found only with the Simple format)


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 221

def self.from_georss_with_tags(georss)
  georss_parser = GeorssParser.new
  georss_parser.parse(georss, true)
  [georss_parser.geometry, georss_parser.georss_tags]
end

.from_hex_ewkb(hexewkb) ⇒ Object

Creates a geometry based on a HexEWKB string given.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 195

def self.from_hex_ewkb(hexewkb)
  factory = GeometryFactory.new
  hexewkb_parser = HexEWKBParser.new(factory)
  hexewkb_parser.parse(hexewkb)
  factory.geometry
end

.from_kml(kml) ⇒ Object

Sends back a geometry from a KML encoded geometry string.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 228

def self.from_kml(kml)
  factory = GeometryFactory.new
  parser = KmlParser.new(factory)
  parser.parse(kml)
end

Instance Method Details

#as_ewkb(allow_srid = true, allow_z = true, allow_m = true) ⇒ Object

Outputs the geometry as an EWKB string.

The allow_srid, allow_z and allow_m arguments allow the output to include srid, z and m respectively if they are present. If these arguments are set to false, srid, z and m are not included, even if they are present in the geometry. By default, the output string contains all the information in the object.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 57

def as_ewkb(allow_srid = true, allow_z = true, allow_m = true)
  ewkb = 1.chr # little_endian by default

  type = binary_geometry_type
  type |= Z_MASK if @with_z && allow_z
  type |= M_MASK if @with_m && allow_m

  if allow_srid
    type = type | SRID_MASK
    ewkb << [type, @srid].pack('VV')
  else
    ewkb << [type].pack('V')
  end

  ewkb  << binary_representation(allow_z, allow_m)
end

#as_ewkt(allow_srid = true, allow_z = true, allow_m = true) ⇒ Object

Outputs the geometry as an EWKT string.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 100

def as_ewkt(allow_srid = true, allow_z = true, allow_m = true)
  if allow_srid
    ewkt = "SRID=#{@srid};"
  else
    ewkt = ''
  end
  ewkt << text_geometry_type  # to distinguish the M from the Z when there is actually no Z...

  ewkt << 'M' if @with_m && allow_m && (!@with_z || !allow_z)
  ewkt << '(' << text_representation(allow_z, allow_m) << ')'
end

#as_georss(options = {}) ⇒ Object

Outputs the geometry in georss format. Assumes the geometries are in latlon format, with x as lon and y as lat. Pass the :dialect option to swhit format. Possible values are: :simple (default), :w3cgeo and :gml.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 123

def as_georss(options = {})
  dialect = options[:dialect] || :simple
  case (dialect)
  when :simple
    geom_attr = ''
    if options[:featuretypetag]
      geom_attr += " featuretypetag=\"#{options[:featuretypetag]}\""
    end
    if options[:relationshiptag]
      geom_attr += " relationshiptag=\"#{options[:relationshiptag]}\""
    end
    geom_attr += " floor=\"#{options[:floor]}\"" if options[:floor]
    geom_attr += " radius=\"#{options[:radius]}\"" if options[:radius]
    geom_attr += " elev=\"#{options[:elev]}\"" if options[:elev]
    georss_simple_representation(options.merge(geom_attr: geom_attr))
  when :w3cgeo
    georss_w3cgeo_representation(options)
  when :gml
    georss_gml_representation(options)
  end
end

#as_hex_ewkb(allow_srid = true, allow_z = true, allow_m = true) ⇒ Object

Outputs the geometry as a HexEWKB string. It is almost the same as a WKB string, except that each byte of a WKB string is replaced by its hex 2-char representation in a HexEWKB string.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 86

def as_hex_ewkb(allow_srid = true, allow_z = true, allow_m = true)
  as_ewkb(allow_srid, allow_z, allow_m).unpack('H*').join('').upcase
end

#as_hex_wkbObject

Outputs the geometry as a strict HexWKB string


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 93

def as_hex_wkb
  as_hex_ewkb(false, false, false)
end

#as_json(_options = {}) ⇒ Object Also known as: as_geojson


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 179

def as_json(_options = {})
  # Implemented by each class
end

#as_kml(options = {}) ⇒ Object

Iutputs the geometry in kml format : options are :id, :tesselate, :extrude, :altitude_mode. If the altitude_mode option is not present, the Z (if present) will not be output (since it won't be used by GE: clampToGround is the default)


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 149

def as_kml(options = {})
  id_attr = ''
  id_attr = " id=\"#{options[:id]}\"" if options[:id]

  geom_data = ''
  if options[:extrude]
    geom_data += "<extrude>#{options[:extrude]}</extrude>\n"
  end
  if options[:tesselate]
    geom_data += "<tesselate>#{options[:tesselate]}</tesselate>\n"
  end
  if options[:altitude_mode]
    geom_data += "<altitudeMode>#{options[:altitude_mode]}</altitudeMode>\n"
  end

  allow_z = (with_z || !options[:altitude].nil?) &&
            (!options[:altitude_mode].nil?) &&
            options[:atitude_mode] != 'clampToGround'
  fixed_z = options[:altitude]

  kml_representation(options.merge(id_attr: id_attr, geom_data: geom_data,
                                   allow_z: allow_z, fixed_z: fixed_z))
end

#as_wkbObject

Outputs the geometry as a strict WKB string.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 77

def as_wkb
  as_ewkb(false, false, false)
end

#as_wktObject

Outputs the geometry as strict WKT string.


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 115

def as_wkt
  as_ewkt(false, false, false)
end

#bounding_boxObject

to be implemented in subclasses


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 34

def bounding_box
end

#envelopeObject

Returns an Envelope object for the geometry


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 44

def envelope
  Envelope.from_points(bounding_box, srid, with_z)
end

#m_rangeObject

to be implemented in subclasses


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 38

def m_range
end

#to_json(options = {}) ⇒ Object

simple geojson representation TODO add CRS / SRID support?


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# File 'lib/geo_ruby/simple_features/geometry.rb', line 175

def to_json(options = {})
  as_json(options).to_json(options)
end