Geographic Document Architecture. Exchange mechanism (proposed) which organizes data into components called Content Architectures. This is similar to the concept of Office Document Architecture (ODA). GDA supposes that with many different standards for GIS interchange coming into existence and with there being little chance of convergence, some mechanism which separates content and carrier be devised. For each content type, a Content Architecture would be developed. For all Content Architectures, the same data coding and encapsulation techniques would be used.