Infrastructures to improve user access to EO data

Kurzfassung

A huge and permanently increasing amount of remote sensing data has to be archived and is supposed to be utilized. Therefore the classical issues of long term preservation of products of various missions and sensors have to joined with easy and open data access. To cope with requirements of both aspects a separation of core systems and user information services (UIS) is indicated. This separation of duties generates flexibility in connecting multiple data sources with several user service systems. The German Remote Sensing Data Center (DLR) has developed and is operating the Data Information and Management System (DIMS). The main component of the core part of DIMS is a digital library, the so-called Product Library. It is composed of an inventory part hosting the metadata of all remote sensing products and an archive part with a hierarchical storage management system for product files. The Product Library provides the product reference by a consistent metadata and data management as well as data security. Further core components of DIMS manage user orders, customer information, product order options and production workflows. Processing systems are connected to process and format products or to generate delivery products for online or offline distribution. In comparison to the functionalities of the core components, the user information services provide the public access to the valuable products. In a user information service the emphasis lies on the user point of view to the data. Usually, higher level products are offered which can be used immediately without further processing steps. The products offered may exist as such in the core system, or they are producible on demand. This way additional products are offered which will be generated by a post-processing step performing tailoring of products originating from the core system. Therefore, the product collections in a user information service will be quite different to the ones in a core system. For external users the data source is of marginal interest, so the collections are sorted thematically. Quick search and user friendly ordering features are important issues in this domain. The first part of this paper presents the bridge between the DIMS core systems and the user information services. Data from one Product Library has to be loaded to different portals for data access and also data from different Product Libraries can be provided in one user information service. With the UIS-to-core interface component of DIMS it is possible to exchange products and order/user information by appropriate mechanisms including trigger, timer and query. Upload of new products or product updates in one-by-one or bulk mode can be configured. User orders can be mapped to and from user information services of different organizations, e.g. ESA or EUMETSAT. In the second part common, underlying hardware aspects are discussed to improve access to Earth Observation data. Future Earth Observation (EO) missions have also new challenges to the EO data management. Raw data and products are larger and new applications (real time, near real time) need the products in shorten time. But experiences of the last years show that a detached reflection on reduced access time to the archive will not lead automatically to shorten delay for the provision of user products. An integral approach to the whole production chain of user products enables the application of new storage architectures in the remote sensing settings which is necessary for future missions. After a short description and analysis of the existing infrastructure the second part of this paper provides proposals of a set of guidelines and suggestions for the application of new storage architectures. These proposals will be subjected to some tests whose first results round off this lecture.