Frequently Asked Questions

What is EPOS?

EPOS stands for the European Plate Observing System. It is a unique e-infrastructure and collaborative environment for the solid earth science community. It covers a wide range of aspects which are grouped in various “Thematic Core Services” (TCS). This website is part of the TCS GNSS Data & Products. More information about this TCS can be found on their landing page.

Who provides the GNSS data?

The GNSS data comes from various national and regional GNSS networks. Many of them are part of the EUREF Permanent GNSS Network which is contributing to EPOS. Other examples are the French RENAG and the Italian RING networks. Information about the stations and their meta-data can be found at M3G. The actual RINEX data can be downloaded from GNSS Data Gateway. More information can also be found on the afore mentioned landing page.

Who computes the position time series, velocities and strain rates?

In EPOS there are various Analysis and Combination centres which are listed here. The position time series have been subjected to quality control and can be directly used for geophysical research. From these time series the velocity has been estimated. From the velocity field, a strain rate map has been computed. Which analysis/combination centre provides which type of product is listed in the table below.

Why do I need to login to download the products?

The products are free to download but to ensure continuous funding of this service, we would like to know who is downloading them. This will help us to obtain Key Performance Indicators (KPIs) that are quantifiable measurements to gauge our webservice overall long-term performance. For similar reasons, we request that the DOI's of the products are mentioned in any publication using our products. However, only an email is compulsory for creating an account. This is needed because products requested for multiple stations are sent to the user by email.

How do I automate download of the products?

The GNSS product portal makes use of RESTful API requests to our GLASS node that has all products in its database. The list of API's is given here

An example of how the product GLASS node can be queried is:

curl -X GET "https://gnssproducts.epos.ubi.pt/GlassFramework/webresources/products/velocities/BLIX/UGA-CNRS/xyz/json" -H "accept: application/json"

The result of this query is:

            [
              {
                "velz_sigma": 0.000542,
                "vel_rho_xz": 0.842543,
                "velx_sigma": 0.000557,
                "vel_rho_xy": 0.255307,
                "vel_rho_yz": 0.248058,
                "velz": 0.011762,
                "vely": 0.018921,
                "velx": -0.012973,
                "vely_sigma": 0.000211
              }
            ]