Extended Data
                                            KML 2.2 provides the option to store attribute data in individual placemarks using either <Data> or <SchemaData> elements. For background, please read: https://developers.google.com/kml/documentation/extendeddata?csw=1.
The key distinction between Data, and SchemaData is that SchemaData elements are associated with formal schema definitions in <Schema> elements.
The following element attributes are used by the KML reader and writer to read/write KML 2.2 extended data.
The KML reader and writer use a set of kml_data and kml_schema_data structured list attributes to read/write extended data.
| 
                                                             KML Element Attribute  | 
                                                        
                                                             KML Element  | 
                                                    
| 
                                                             kml_data{}.name  | 
                                                        
                                                             name attribute of <Data>  | 
                                                    
| 
                                                             kml_data{}.value  | 
                                                        
                                                             <Data><value>  | 
                                                    
| 
                                                             kml_data{}.display_name  | 
                                                        
                                                             <Data><displayName> Optional. Note   xml entities will be encoded on writing. 
                                                         | 
                                                    
| 
                                                             kml_data{}.display_name_raw_text  | 
                                                        
                                                             <Data><displayName> Optional. Note  Display_name values will written as raw text, i.e., xml entities will not be encoded. CDATA blocks should be added as necessary. 
                                                         | 
                                                    
| 
                                                             kml_schema_url  | 
                                                        
                                                             schemaUrl attribute of <SchemaData>  | 
                                                    
| 
                                                             kml_schema_data{}.name  | 
                                                        
                                                             name attribute of <SimpleData>  | 
                                                    
| 
                                                             kml_schema_data{}.value  | 
                                                        
                                                             Value of <SimpleData>  |