GNSS data of thousands of stations in Europe is stored on various servers, called nodes, across various countries. One of the objectives of the EPOS TCS GNSS Data and Products was to develop a software that would make the data from all these nodes discoverable using queries and to facilitate their download. The name of this software is GLASS (Geodetic Linking Advanced Software System). It will also be used to disseminate the derived GNSS products to the EPOS ecosystem.
The development of this software package is nearing its completing and we are now in the testing phase. To distribute the software to the various partners, the UBI team has put together a virtual machine, or simply VM, with most of the software that all partners have been developing pre-compiled and installed.
The virtual machine has been developed using Vagrant which is a wrapper for building and managing virtual machines. In this particular case, the virtual machine was created using the Oracle VirtualBox engine.
Easy-to-use – “The way it works is very simple: you just add the Box file to Vagrant, boot it up, configure the network, access the virtual machine and in the terminal type ‘startglass’ to execute a standard startup script. Once the start-up process is completed you should be able to fully use all the processing and visualization capabilities that were inserted in the VM”, explains Paul Crocker from UBI team. However, he also adds that as each site (node) where GNSS station data is managed is different it still means that the configuration of many parameters cannot be avoided.
Usefulness – The GLASS virtual machine is very useful for developing and testing purposes and for getting to know all the software from WP10, and this is its prime purpose, it is an alternative to the download, compilation and configuration of all the individual packages and dependencies. The VM is therefore very useful in the scope of developing, testing and training. The VM can also be used in a production environment for managing data from networks of GNSS stations, after suitable security precautions are taken into consideration, such a turn key solution may be desirable and the UBI team will work towards this goal.
Tools installed on the virtual machine – The VM contains the following core tools necessary for a Glass Node installation (between parentheses is the partner who was largely responsible for the development):
► The Database schema necessary for storing all metadata (IMO)
► IndexGD tool for indexing RINEX files (OCA)
► DB-API tool for inserting metadata, site logs, Rinex files, in the DB. (IMO and OCA)
► GlassFramework API tool that serves the metadata stored in the database (UBI)
► Anubis and RunQC tools to check the quality of the GNSS data (GOP)
► Synchronization system tool to synchronize metadata between nodes (UBI)
► Monitor Data Gateway (DGW) tools to control interaction between M3G and the data gateway (OCA)
Graphical Web Applications – The VM also contains Graphical Web Applications to help in visualization and administration:
► Glass Web Client GUI to visualize metadata stored in DB (OCA)
► Products Portal GUI to visualize GNSS data derived products (UBI)
► Node Manager GUI to manage the local node information (UBI)
Set of tools – With this set of tools, it is possible to fully to manage the functionality of the nodes. According to Rafael Couto, from UBI team, it is possible to insert new metadata, visualize all the data and metadata inserted in the database, check the quality of the data and interact with other testing partners using the synchronization tools.
“By putting all the development made until now together in just one virtual machine, we count on an integrated testing process and a more effectiveness way to fix bugs”, highlights Rui Fernandes, coordinator of the EPOS TCS GNSS Data and Products.
The Virtual Machine and its software are, however, not the only step necessary to join the EPOS network. Information about stations and networks that are being offered must be previously inserted using the M3G website, “which is a dedicated tool where each data supplier must make sure that the metadata of its GNSS stations are properly maintained”, explains Machiel Bos, from UBI team.
Virtualization – In terms of future work concerning virtualization, the UBI group is currently working on a more lightweight, approach using Docker containers, thereby giving developers and deployers more options when considering the installation of software components from WP10.
Metadata – Station metadata is the chronological description of the equipment at a GNSS station. Incorrect station metadata can cause errors in the computed coordinate positions. To avoid such errors, it is important that the researcher who analyses the GNSS data from the station has access to the full set of station metadata. Each data supplier must make sure that the metadata of its GNSS stations are properly maintained. The GNSS TCS developed a dedicated tool (M3G) for this.
More information on using and obtaining the virtual machine – http://glass.c4g-pt.eu/epos_vm
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