About TGM

Since the Institute of Earth Sciences, Academia Sinica (IES) established its first continuous Global Navigation Satellite System (GNSS) station, S01R, in Baisha, Penghu Island, more than 400 continuous GNSS stations have been set up by several institutes and universities operating daily until now. Data from these stations have been used to produce high-precision, three-component velocity fields as well as position time series that track time-varying crustal deformation from small interesting area to the entire Island of Taiwan. In order to keep receiving as well as analyzing these valuable and enormous data, a huge investment of manpower and material resources is required from fields to laboratories. Since the field conditions are controlled by the installation agency, careful handling of the data collected from all corporate partners is even more important. To achieve the goal of providing a fast service of data collecting and coordinate positioning for earth sciences research. The Taiwan Geodetic Model (TGM) platform originated by IES aims to increase the quantity and availability of the data and to deliver products based on the raw data. High quality computed products such as stations positions, time series, velocities and strain rate fields provide researchers in Earth Science with relevant information for finding new data patterns, making new discoveries and even creating new science.

TGM platform framework

The TGM is an open source platform with web interface to capture data from a variety of continuous GNSS stations operating in Taiwan encompassing several key elements : (1) the metadata of continuous GNSS stations, which includes the supervising institute or organization responsible for operating the station, the location of the station, maintenance records for the station's instruments and equipment and raw data availability; (2) the data download portal, which provides downloads of standard RINEX (Receiver Independent Exchange Format) data files older than six months for all continuous GNSS stations maintained by IES in both single or batch download job; (3) the time series interactive viewer, which exhibits complete time series of all the continuous GNSS stations after installation. In addition to the original raw time series, functional choices are provided to fit time series data with coseismic offsets and postseismic deformation associated with moderate to large earthquakes or/and seasonality variations due to annual water storage change, the long-term linear velocity etc; (4) the product portal, which provides latest velocity and strain rate visualization maps, as well as coseismic displacement data, for inland earthquakes with a magnitude larger than 6.0.