class RGeo::CoordSys::CS::GeographicCoordinateSystem

OGC spec description

A coordinate system based on latitude and longitude. Some geographic coordinate systems are Lat/Lon, and some are Lon/Lat. You can find out which this is by examining the axes. You should also check the angular units, since not all geographic coordinate systems use degrees.

Attributes

angular_unit[R]

Returns the AngularUnit. The angular unit must be the same as the CS_CoordinateSystem units.

prime_meridian[R]

Returns the PrimeMeridian.

Public Class Methods

create(name_, angular_unit_, horizontal_datum_, prime_meridian_, axis0_, axis1_, *optional_) click to toggle source

Create a GeographicCoordinateSystem, given a name, an AngularUnit, a HorizontalDatum, a PrimeMeridian, and two AxisInfo objects. The AxisInfo objects are optional and may be set to nil. You may also provide the optional parameters specified by the Info interface.

# File lib/rgeo/coord_sys/cs/entities.rb, line 1500
def create(name_, angular_unit_, horizontal_datum_, prime_meridian_, axis0_, axis1_, *optional_)
  new(name_, angular_unit_, horizontal_datum_, prime_meridian_, axis0_, axis1_, *optional_)
end

Public Instance Methods

get_axis(index_) click to toggle source

Implements RGeo::CoordSys::CS::CoordinateSystem#get_axis

# File lib/rgeo/coord_sys/cs/entities.rb, line 1456
def get_axis(index_)
  index_ == 1 ? @axis1 : @axis0
end

get_units(index_) click to toggle source

Implements RGeo::CoordSys::CS::CoordinateSystem#get_units

# File lib/rgeo/coord_sys/cs/entities.rb, line 1449
def get_units(index_)
  @angular_unit
end

get_wgs84_conversion_info(index_) click to toggle source

Gets details on a conversion to WGS84. Some geographic coordinate systems provide several transformations into WGS84, which are designed to provide good accuracy in different areas of interest. The first conversion (with index=0) should provide acceptable accuracy over the largest possible area of interest.

# File lib/rgeo/coord_sys/cs/entities.rb, line 1474
def get_wgs84_conversion_info(index_)
  @horizontal_datum.wgs84_parameters
end

num_conversion_to_wgs84() click to toggle source

Gets the number of available conversions to WGS84 coordinates.

# File lib/rgeo/coord_sys/cs/entities.rb, line 1463
def num_conversion_to_wgs84
  @horizontal_datum.wgs84_parameters ? 1 : 0
end