.. _intro_proc_sh_glred:

:program:`sh_glred`
===================

To use :program:`sh_glred` to obtain a time series of position estimates, you need to edit one and possibly more control files in the :file:`gsoln/` directory established by :program:`sh_setup`.
In the simplest case, in which you want to use all of the sites in your GAMIT solutions and are not combining these solutions with h-files from an external source, you need only edit :file:`glorg.cmd` to specify which sites will be used to define your reference frame.
If you want to omit some sites or indicate where steps should be applied in the time series to account for earthquakes or changes in instrumentation, you may need to edit also :file:`globk.cmd` and an earthquake/rename file.
These are described in :numref:`intro_proc_globk`.
Then run, e.g.,

.. code-block:: console

   $ sh_glred -expt emed -s 2018 34 2018 36 -opt H G T >&! sh_glred.log

The :option:`H` option tells :program:`sh_glred` to translate GAMIT h-files in the day directory to GLOBK binary h-files and put them into :file:`glbf/`;
:option:`G` indicates that :program:`glred` is to be run (you can use :program:`sh_glred` just to do the h-file translation if you wish);
and :option:`T` indicates that time series plots are to be generated using :program:`sh_plot_pos` (invoking first :program:`tssum`, the program that extracts coordinates from the :program:`glred` output :file:`.org` file to produce :file:`.pos` files).
Prior to Release 10.6, the coordinates could be extracted only with programs :program:`ensum` and :program:`multibase` to produce :file:`mb` files and plotted with :program:`sh_plotcrd`.
This option is still available in 10.7 with key letter :option:`E` but will be deprecated in future releases.
Finally, it is possible to combine the h-files you have created in the day directories with global or regional h-files generated by an external processing center (e.g. MIT or SOPAC), using the :content:`hfnd` token in the project :file:`tables/process.defaults` (see :numref:`intro_proc_process.defaults`).

:program:`sh_glred` uses the :option:`-netext` option with one or more GNSS (or other netext) codes to select which day directories to access for GAMIT h-files, appending a (lowercase) letter to the GLOBK binary h-file to distinguish among files in the :program:`globk` :file:`.gdl` list.