Class: Proj4::Projection

Inherits:
Object
  • Object
show all
Includes:
Tools
Defined in:
lib/ffi-proj4/projection.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Tools

#bool_result, #deg_to_rad, #rad_to_deg

Constructor Details

#initialize(arg, auto_free = true) ⇒ Projection

Returns a new instance of Projection.



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# File 'lib/ffi-proj4/projection.rb', line 11

def initialize(arg, auto_free = true)
  args = case arg
    when Array
      arg.collect { |a| a.sub(/^\+/, '') }
    when String
      arg.strip.split(/ /).collect { |a| a.sub(/^\+/, '') }
    when Hash
      arg.collect { |k, v|
        if v.nil?
          k.to_s
        else
          "#{k.to_s.strip}=#{v.to_s.strip}"
        end
      }
    when Proj4::Projection
      arg.definition.strip.split(/ /).collect { |a| a.sub(/^\+/, '') }
    else
      raise ArgumentError.new("Unknown type #{arg.class} for projection definition")
  end

  params = args.collect(&:strip).collect { |a|
    if !(a =~ /^\+/)
      "+#{a}"
    else
      a
    end
  }.join(' ')

  ptr = FFIProj4.pj_init_plus(params)

  if ptr.null?
    errno = FFIProj4.pj_get_errno_ref.read_int
    raise ProjectionParseError.new(FFIProj4.pj_strerrno(errno))
  else
    @ptr = FFI::AutoPointer.new(
      ptr,
      auto_free ? self.class.method(:release) : self.class.method(:no_release)
    )
  end
end

Instance Attribute Details

#ptr ⇒ Object (readonly)

Returns the value of attribute ptr.



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# File 'lib/ffi-proj4/projection.rb', line 9

def ptr
  @ptr
end

Class Method Details

.no_release(ptr) ⇒ Object

:nodoc:



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# File 'lib/ffi-proj4/projection.rb', line 52

def self.no_release(ptr) #:nodoc:
end

.release(ptr) ⇒ Object

:nodoc:



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# File 'lib/ffi-proj4/projection.rb', line 55

def self.release(ptr) #:nodoc:
  FFIProj4.pj_free(ptr)
end

Instance Method Details

#datum_transform(proj, x, y, z = nil) ⇒ Object Also known as: datum_transform_rad 



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# File 'lib/ffi-proj4/projection.rb', line 154

def datum_transform(proj, x, y, z = nil)
  if !proj.is_a?(Proj4::Projection)
    raise ArgumentError.new("Expected a Proj4::Projection")
  end

  x_ptr = FFI::MemoryPointer.new(:double)
  y_ptr = FFI::MemoryPointer.new(:double)
  z_ptr = FFI::MemoryPointer.new(:double) unless z.nil?

  x_ptr.write_double(x)
  y_ptr.write_double(y)
  z_ptr.write_double(z) unless z.nil?

  result = FFIProj4.pj_transform(self.ptr, proj.ptr, 1, 1, x_ptr, y_ptr, z_ptr)

  if result >= 0 && !bool_result(result)
    Point.new(
      x_ptr.read_double,
      y_ptr.read_double,
      z_ptr.read_double
    )
  else
    raise TransformError.new(FFIProj4.pj_strerrno(result))
  end
end

#datum_transform_deg(proj, x, y, z = nil) ⇒ Object 



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# File 'lib/ffi-proj4/projection.rb', line 181

def datum_transform_deg(proj, x, y, z = nil)
  self.datum_transform(proj, x, y, z).tap { |ret|
    ret.x = rad_to_deg(ret.x)
    ret.y = rad_to_deg(ret.y)
    ret.z = rad_to_deg(ret.z)
  }
end

#definition ⇒ Object 



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# File 'lib/ffi-proj4/projection.rb', line 67

def definition
  @definition ||= FFIProj4.pj_get_def(self.ptr, 0).strip
end

#definition_as_hash ⇒ Object 



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# File 'lib/ffi-proj4/projection.rb', line 71

def definition_as_hash
  self.definition.split(/ /).inject({}) { |memo, opt|
    memo.tap {
      k, v = opt.split(/=/)
      k.sub!(/^\+/, '')
      v = true if v.nil?
      memo[k.to_sym] = v
    }
  }
end

#forward(x, y) ⇒ Object Also known as: forward_deg

end alias :inspect :to_s



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# File 'lib/ffi-proj4/projection.rb', line 87

def forward(x, y)
  xy = ProjXY.new(x, y)
  ret = FFIProj4.pj_fwd(xy, self.ptr)
  errno = FFIProj4.pj_get_errno_ref.read_int
  if errno == 0
    Point.new(ret[:x], ret[:y])
  else
    raise TransformError.new(FFIProj4.pj_strerrno(errno))
  end
end

#forward_rad(x, y) ⇒ Object 



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# File 'lib/ffi-proj4/projection.rb', line 99

def forward_rad(x, y)
  self.forward(deg_to_rad(x), deg_to_rad(y))
end

#geocentric? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ffi-proj4/projection.rb', line 63

def geocentric?
  bool_result(FFIProj4.pj_is_geocent(self.ptr))
end

#inverse(x, y) ⇒ Object Also known as: inverse_deg 



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# File 'lib/ffi-proj4/projection.rb', line 103

def inverse(x, y)
  xy = ProjXY.new(x, y)
  ret = FFIProj4.pj_inv(xy, self.ptr)
  errno = FFIProj4.pj_get_errno_ref.read_int
  if errno == 0
    Point.new(ret.x, ret.y)
  else
    raise TransformError.new(FFIProj4.pj_strerrno(errno))
  end
end

#inverse_rad(x, y) ⇒ Object 



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# File 'lib/ffi-proj4/projection.rb', line 115

def inverse_rad(x, y)
  self.inverse(deg_to_rad(x), deg_to_rad(y))
end

#lat_long? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ffi-proj4/projection.rb', line 59

def lat_long?
  bool_result(FFIProj4.pj_is_latlong(self.ptr))
end

#transform(proj, x, y, z = nil) ⇒ Object Also known as: transform_rad 



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# File 'lib/ffi-proj4/projection.rb', line 119

def transform(proj, x, y, z = nil)
  if !proj.is_a?(Proj4::Projection)
    raise ArgumentError.new("Expected a Proj4::Projection")
  end

  x_ptr = FFI::MemoryPointer.new(:double)
  y_ptr = FFI::MemoryPointer.new(:double)
  z_ptr = FFI::MemoryPointer.new(:double)

  x_ptr.write_double(x)
  y_ptr.write_double(y)
  z_ptr.write_double(z.nil? ? 0 : z)

  result = FFIProj4.pj_transform(self.ptr, proj.ptr, 1, 1, x_ptr, y_ptr, z_ptr)

  if result >= 0 && !bool_result(result)
    Point.new(
      x_ptr.read_double,
      y_ptr.read_double,
      z_ptr.read_double
    )
  else
    raise TransformError.new(FFIProj4.pj_strerrno(result))
  end
end

#transform_deg(proj, x, y, z = nil) ⇒ Object 



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# File 'lib/ffi-proj4/projection.rb', line 146

def transform_deg(proj, x, y, z = nil)
  self.transform(proj, x, y, z).tap { |ret|
    ret.x = rad_to_deg(ret.x)
    ret.y = rad_to_deg(ret.y)
    ret.z = rad_to_deg(ret.z)
  }
end