The ztd estimated values from three models named Site-wise, Grid-wise, and GPT3 and the ztd reference values provided by IGS between 2016 and 2020.

The data includes the zenith total delay (ztd) values computed by three models provided by the VMF data server, namely Site-wise, Grid-wise, and GPT3, for target stations during the period from 2016 to 2020, along with the corresponding ztd values extracted from IGS-ztd for the respective sites and epochs.

These data are utilized for specific accuracy analysis and model evaluation.