Opengis Progress toward Interoperability in Photogrammetry

The achievement of interoperability in photogrammetry is a difficult task. Today's photogrammetric services and servers tend to be tightly linked to proprietary environments, supported by heterogeneous platforms, distributed across networks not designed for shared image-related processes, and often are specific to one family of sensors. Interoperability, on the other hand, demands immediate access to any imagery, the image's geo-positioning information, and all photogrammetric processes that might display or otherwise exploit the image, whether these are distributed or heterogeneous or both, for the accomplishment of complex work flows in a single session. The key to progress toward interoperability in photogrammetry is consensus in the marketplace at the level of software interfaces. There are two consequences of consensus interfaces: 1) interoperability (the ability of processing components to cooperate, even when they are designed independently of each other), and 2) commodity software components that will change the face of the marketplace. The interfaces must be carefully placed, however, if the photogrammetric software components are to thrive in the marketplace. This paper reports on the progress made at the Open GIS Consortium, Inc. (OGC) toward market consensus on those interfaces. The organization and status of the Open GIS Consortium is introduced, and a vision of the photogrammetry and remote sensing marketplaces of the future is presented. The technology development methods of the Consortium are summarized, and a brief status report is given, with emphasis on the objects and methods already held in the consensus of OGC, and their relationships to photogrammetric objects. Examples showing how the Consortium is empowering its members to both guide and reflect the evolving digital image and remote sensing marketplace are given, with special attention to new infrastructure and new client services that open fresh market niches for entrepreneurs and that will enormously expand the size of the overall marketplace. The remainder of the paper charts likely future directions of the Consortium. Highlighted are the candidate objects of photogrammetry: images and other grid coverages, stored functions, evaluators, monoand stereoscopic photogrammetric models, accuracy and quality models, attributes and their values, metadata, photogrammetric processes, and their attributes and associations. Special attention is given to the methods (or "behaviors") supported by each class that enable interoperability. The OGC approach exploits the fact that images and other photogrammetric objects are subclasses of "GIS Feature," and so inherit many useful properties and behaviors from this and other more abstract object classes. The paper presents two alternative approaches to the "stored function" objects that enable the communication of photogrammetric equations between clients and servers in a distributed environment, even between software components that were developed without knowledge of each other. The concept of class "folders" is also discussed, in terms of future "shrink-wrap software components" that can carry the OGC certification mark. Finally, because interoperability is heavily dependent upon object-oriented design tools, we provide a summary of the software engineering tools in use at the Consortium, the role played by them, and the future impact of better object tools.