The HMA-I study phase is now completed.
Scenarios & High-level Requirements
The initial phase of the project, up to the System Requirements Review (SRR), has been mainly focused on agreeing with all the partners on a set of operational scenarios and requirements that would form the basis of the definition of the system and its interfaces. All parties were involved in this process by ways of workshops and direct contributions.
- This phase concluded with the production of the HMA Operational
- Technical Note and of the HMA Requirements Baseline document.
Service Specifications and ICD’s
The HMA project focused on the definition of 5 interfaces:
1. Catalogue service, to browse and retrieve metadata on collections and products available across the HMA collaborating catalogues
2. Ordering service, to order products identified in a catalogue
3. Programming Service, to place request for new acquisitions onto the HMA partner missions’ ground segments
4. Mission Planning Service, to facilitate programming requests preparation
5. Online Data Access Services, to retrieve products from the online access archives offered through the HMA
The first issue of the HMA catalogue ICD was submitted to OGC as a profile of the CSW 2.0 OGC catalogue specifications. This profile, the EO Application Profile for CSW 2.0, is compliant with the ISO Application Profile for CSW 2.0.Due to a change of orientation in OGC, pushing towards adopting the ebRIM model for all catalogue services, the HMA specifications were changed to become a profile of the ebRIM.
EO Profile Schema
The figure above describes the layered structure of the schema used to define the different classes of product metadata. The layer structure means that the upper layer main element type is defined by extending a type from the lower level schema. The top layer is mission type specific (e.g. radar missions), the HMA layer is generic to all mission types but is no covered in the ISO and GML layers.
This Ordering ICD describes a profile to order Earth Observation data products. The final goal is to agree to a coherent set of interfaces for ordering of EO products to support access to data from heterogeneous systems dealing with derived data products from satellite based measurements of the earth’s surface and environment.
The service proposed in this implementation specification is intended to support the ordering of Earth Observation (EO) data products either from previously identified data set collections via a typical catalogue interaction or from future acquisitions specified via a Programming service [OR6]. The intent of this specification is to describe an interface that can be supported by many data providers (satellite operators, data distributors, etc.), most of whom have existing (and relatively complex) facilities for the management of these data.
The Ordering Service ICD was originally specified on the basis of the ESA EOLI-XML specification as no suitable OGC baseline was found. The operations were later harmonised with the ones of the SPS profile.
The Programming service ICD has been created as a profile of the OGC SPS base specifications. This candidate implementation specification document explains how Sensor Planning Service is organised and implemented for the Earth Observation domain.
The final goal is to agree to a coherent set of interfaces for sending a programming request for EO products to support access to data from heterogeneous systems dealing with derived data products from satellite based measurements of the earth’s surface and environment.
The SPS configuration proposed in this profile is intended to support the programming process of Earth Observation (EO) sensors system. This profile describes a consistent SPS configuration that can be supported by many satellite data providers, most of whom have existing facilities for the management of these programming requests.
The Sensor Planning Service (SPS) is intended to provide a standard interface to collection assets (i.e., sensors, and other information gathering assets) and to the support systems that surround them. Not only must different kinds of assets with differing capabilities be supported, but also different kinds of request processing systems, which may or may not provide access to the different stages of planning, scheduling, tasking, collection, processing, archiving, and distribution of requests and the resulting observation data and information that is the result of the requests. The SPS is designed to be flexible enough to handle such a wide variety of configurations.
Mission Planning Services
This service is to be provided through 2 main components:
- A central HM Feasibility server, capable of answering all user requests for quick feasibility assessments
- A (set of) higher-level services, such as operator based services, to handle more complex data requests through the DAIL. Such a high-level service could be used to manage the GMES related acquisitions
The programming and ordering ICD cover the needs of both these services.
Online Data Access Services
The following Online Data Access services have been identified for HMA:
- On-line collection: the product is available on the network via FTP / HTTP / etc.; the URL of the product is available in the product metadata attributes of the Catalogue and the data can be retrieved following a catalogue search. No additional ICD necessary to implement this service.
- On-line access: the product data is not already on-line available, but will be made so on user request. This service is provided as a dissemination option of the Ordering service and other ICD is needed.
- On-line consumption: the data required by the user is not delivered to it, but it is published on a server and made available to it via the OGC-WMS or OGC-WCS interfaces. Existing standard ICD’s (e.g. OGC web services) will be used for these services.
- Virtual FTP Service: its aim is to provide a centralised access to different remote servers hosting Earth Observation product data. No additional ICD necessary to implement this service.
The following ICD’s and the application schema, resulting from the efforts on the above topics, are among the most significant outputs of the HMA-I project:
- OGC 06-080 GML 3.1.1 Application schema for Earth Observation
- OGC 06-131 OGC Catalogue Services Specification 2.0 Extension Package
for ebRIM (ISO/TS 15000-3) Application Profile
- OGC 06-141 Ordering Services for Earth Observation Products
- OGC 07-018 Opengis Sensor Planning Service Application Profile for EO
The latest versions of the above documents and a baseline for all HMA specifications are available on the HMA WIKI.