ONDA and DIAS (Data and Information Access Services) Overview
ONDA is a platform enabling users to host data and to build their applications in the Cloud.
ONDA achieve this by fostering the exploitation of the freely available Earth Observation satellites Data and geospatial Information and by providing Access to Services for the development of new solutions.
In order to facilitate the use of Earth Observation satellite data and geospatial information, ONDA provides the added values of:
- full availability of all Copernicus data
- customisable solutions for diverse requirements and levels of expertise
- innovative data access technology (ENS, see below) allowing users to easily extract only the needed product information
ONDA do this by offering free solutions to all users for easily accessing, downloading and processing a wealth of data and information as well as fee-based services that benefit from the performance of our Cloud environment.
If you want to know more about ONDA.
ENS (Elastic Node Server) Overview
Elastic Node Server (ENS) is an Open Source software providing a simple and scalable front-end to one or more Data Storages for use with client Computing Instances. Elastic Node Server (ENS) extends traditional File or Object Storages by exposing not only standard Directories and Files but breaking them down further in a logical tree of Nodes up to the tiniest piece of information. ENS Nodes can be located, queried and accessed semantically via their names disregarding their physical formats and locations.
Once mounted on Computing Instances, Elastic Node Server (ENS) takes charge of the complexity of Files opening, format discovery, public or private library linking and any required data access engineering skill to finally expose the resulting unified tree of Nodes through standard and well known interfaces as the Network File System (NFS), probably the most wildly used distributed file system, the Common Internet File System (SMB/CIFS), an equivalent for Microsoft clients, or the OpenStack Object Storage (Swift). As such, a bare standard Operating System running modern or legacy software written in whatever language can access the content of a large variety of File formats without any a priori knowledge of their specifications and without linking any software library specific to the accessed data.
Elastic Node Server (ENS) enables unprecedented use cases including extracting data from ZIP, XML, HDF or even binary telemetry data up to the slightest bit from a Shell script, a FORTAN application, Java, C/C++, C#, Word/Excell VBA, etc. without linking or installing anything!
Unified Data Model
ENS can handle a large number of data types through a central and unified data model, clearly separating the data management logic from the implementation details specific to the data formats and access methods. ENS Data Model already supports a large number of data types among which most of the Earth Observation product types e.g. Sentinel-1/2/3 series, ENVISAT ASAR, Landsat-8, etc.
Multi and Standard Interfaces
For a seamless integration from client resources, ENS exposes its data model through various and standard local or networked interfaces as FUSE, NFS, SMB/CIFS or OpenStack Storage (Swift). This design makes ENS easy to mount on Linux, macOS or Windows platforms with standard services usually pre-installed on most platforms
Multi Backing Stores
ENS is a Storage wrapper that supports multiple backing storage types including the so called Block Storages (local or remote File Systems), Object Storage (as OpenStack Object Storage or Amazon S3), or even virtual storages
As a Storage wrapper/handler, ENS is by definition a performance overhead with respect to a direct access to the backing storage. In practice, users and applications don’t need the full content of the standard files or objects in the backing stores especially for Earth Observation data that are increasingly larger. The ease of selection of only the useful part of the data makes ENS faster and more efficient in most use cases
Especially in Cloud environments, a significant part of the costs attached to the storage size and the amount of data transferred from the storage parts to the computing instances. ENS saves a significant amount of space by offering live and optimized access within compressed archives and to scientific data in their native formats e.g. native telemetry. As for performances, the ease of selection of only the useful part of the data makes ENS cheaper in many cases by transferring less data to the computing instances
Scalability & High-Availability
ENS is designed to be integrated with horizontal scalability and high availability. As such, ENS can be operated as a cluster of instances that can be expanded according to the required workload. Single points of failures as proxies can be avoided by automatic failover mechanisms
ENS is a “ready-only” service with respect to the Backing Storages. As such, the data cannot be altered by the users from ENS interfaces. However, ENS supports POSIX compatible Access Control Lists (ACLs) to all or part of the data.
The core part of ENS is a 100% Java application that runs on most operating systems. Some native code maybe involved when absolutely required but this only occurs in dedicated or separate modules or extensions.
ENS is an Open Source Software released under GNU Affero GPL version 3.
If you want to know more about ENS.
ENS Virtual paths (Virtual path to products)
The backend storage contains millions of products. It cannot be believable to display the entire list of products to the end-user via ENS interface into a unique directory container.
The ENS solution is to spread products into directories hierarchy based on the anticipated usages of the end-users.
The complete list of virtual paths for each addon is provided in section below.
Each product of ONDA/DIAS service is decribed by a set of metadata (acquision platform name, times, sensor mode, etc.) These metadata follow the HMA/OGC standard (see http://docs.opengeospatial.org/is/10-157r4/10-157r4.html).
The complete list of metadata for each addon is provided in following section.
List of Addons for ONDA/DIAS
ONDA/DIAS supports the following list of addons: