Initial support Coordinate System Metadata for Proj 9.4 (not released…

… yet)

lib/api/api.rb

@@ -93,7 +93,7 @@ def self.load_api
                   '6.0.0', '6.1.0', '6.2.0', '6.3.0',
                   '7.0.0', '7.1.0', '7.2.0',
                   '8.0.0', '8.1.0', '8.2.0',
-                  '9.1.0', '9.2.0']
+                  '9.1.0', '9.2.0', '9.4.0']
 
       versions.each do |version|
         api_version = Gem::Version.new(version)

lib/api/api_9_4.rb

@@ -0,0 +1,6 @@
+module Proj
+  module Api
+    attach_function :proj_coordinate_metadata_create, [:PJ_CONTEXT, :PJ, :double], :PJ
+    attach_function :proj_crs_has_point_motion_operation, [:PJ_CONTEXT, :PJ], :int
+  end
+end

lib/proj/coordinate_metadata.rb

@@ -0,0 +1,38 @@
+# encoding: UTF-8
+
+module Proj
+  # Coordinate metadata is the information required to make coordinates unambiguous. For a
+  # coordinate set referenced to a static CRS it is the CRS definition. For a
+  # coordinate set referenced to a dynamic CRS it is the CRS definition together
+  # with the coordinate epoch of the coordinates in the coordinate set.
+  #
+  # In a dynamic CRS, coordinates of a point on the surface of the Earth may change with time.
+  # To be unambiguous the coordinates must always be qualified with the epoch at which they
+  # are valid. The coordinate epoch is not necessarily the epoch at which the observation
+  # was collected.
+  class CoordinateMetadata < PjObject
+    # Create a CoordinateMetadata object
+    #
+    # @param crs [Crs] The associated Crs
+    # @param context [Context]. An optional Context
+    # @param epoch [Double]. Epoch at wich the CRS is valid
+    #
+    # @return [CoordinateMetadata]
+    def initialize(crs, context=nil, epoch=nil)
+      ptr = Api.proj_coordinate_metadata_create(context || Context.current, crs, epoch)
+
+      if ptr.null?
+        Error.check_object(self)
+      end
+
+      super(ptr, context)
+    end
+
+    # Returns the coordinate epoch
+    #
+    # @return [Double]
+    def epoch
+      Api.proj_coordinate_metadata_get_epoch(self.context, self)
+    end
+  end
+end

lib/proj/crs.rb

@@ -461,6 +461,14 @@ def coordinate_operation
       self.class.create_object(ptr, self.context)
     end
 
+    # Returns whether a CRS has an associated PointMotionOperation
+    #
+    # @return [Boolean]
+    def point_motion_operation?
+      result = Api.proj_crs_get_coordoperation(self.context, self)
+      result == 1 ? true : false
+    end
+
     # Returns the prime meridian
     #
     # @see https://proj.org/development/reference/functions.html#c.proj_get_prime_meridian

lib/proj/pj_object.rb

@@ -31,6 +31,8 @@ def self.create_object(pointer, context)
                      Ellipsoid
                    when :PJ_TYPE_PRIME_MERIDIAN
                      PrimeMeridian
+                   when :PJ_TYPE_COORDINATE_METADATA
+                     CoordinateMetadata
                    else
                      # Return whatever the current class is
                      self