class RGeo::WKRep::WKTGenerator

This class provides the functionality of serializing a geometry as WKT (well-known text) format. You may also customize the serializer to generate PostGIS EWKT extensions to the output, or to follow the Simple Features Specification 1.2 extensions for Z and M.

To use this class, create an instance with the desired settings and customizations, and call the generate method.

Configuration options

The following options are recognized. These can be passed to the constructor, or set on the object afterwards.

:tag_format: The format for tags. Possible values are :wkt11, indicating SFS 1.1 WKT (i.e. no Z or M markers in the tags) but with Z and/or M values added in if they are present; :wkt11_strict, indicating SFS 1.1 WKT with Z and M dropped from the output (since WKT strictly does not support the Z or M dimensions); :ewkt, indicating the PostGIS EWKT extensions (i.e. “M” appended to tag names if M but not Z is present); or :wkt12, indicating SFS 1.2 WKT tags that indicate the presence of Z and M in a separate token. Default is :wkt11. This option can also be specified as :type_format.
:emit_ewkt_srid: If true, embed the SRID of the toplevel geometry. Available only if :tag_format is :ewkt. Default is false.
:square_brackets: If true, uses square brackets rather than parentheses. Default is false.
:convert_case: Possible values are :upper, which changes all letters in the output to ALL CAPS; :lower, which changes all letters to lower case; or nil, indicating no case changes from the default (which is not specified exactly, but is chosen by the generator to emphasize readability.) Default is nil.

Public Class Methods

new(opts_={}) click to toggle source

Create and configure a WKT generator. See the WKTGenerator documentation for the options that can be passed.

# File lib/rgeo/wkrep/wkt_generator.rb, line 86
def initialize(opts_={})
  @tag_format = opts_[:tag_format] || opts_[:type_format] || :wkt11
  @emit_ewkt_srid = @tag_format == :ewkt ?
    (opts_[:emit_ewkt_srid] ? true : false) : nil
  @square_brackets = opts_[:square_brackets] ? true : false
  @convert_case = opts_[:convert_case]
end

Public Instance Methods

convert_case() click to toggle source

Returns the case for output. See WKTGenerator for details.

# File lib/rgeo/wkrep/wkt_generator.rb, line 113
def convert_case
  @convert_case
end

emit_ewkt_srid?() click to toggle source

Returns whether SRID is embedded. See WKTGenerator for details.

# File lib/rgeo/wkrep/wkt_generator.rb, line 102
def emit_ewkt_srid?
  @emit_ewkt_srid
end

generate(obj_) click to toggle source

Generate and return the WKT format for the given geometry object, according to the current settings.

# File lib/rgeo/wkrep/wkt_generator.rb, line 131
def generate(obj_)
  @begin_bracket = @square_brackets ? '[' : '('
  @end_bracket = @square_brackets ? ']' : ')'
  factory_ = obj_.factory
  if @tag_format == :wkt11_strict
    @cur_support_z = nil
    @cur_support_m = nil
  else
    @cur_support_z = factory_.property(:has_z_coordinate)
    @cur_support_m = factory_.property(:has_m_coordinate)
  end
  str_ = _generate_feature(obj_, true)
  if @convert_case == :upper
    str_.upcase
  elsif @convert_case == :lower
    str_.downcase
  else
    str_
  end
end

square_brackets?() click to toggle source

Returns whether square brackets rather than parens are output. See WKTGenerator for details.

# File lib/rgeo/wkrep/wkt_generator.rb, line 108
def square_brackets?
  @square_brackets
end

tag_format() click to toggle source

Returns the format for type tags. See WKTGenerator for details.

# File lib/rgeo/wkrep/wkt_generator.rb, line 96
def tag_format
  @tag_format
end

Also aliased as: type_format

type_format() click to toggle source

Alias for: tag_format