.. _test_glred_ts:

Run GLOBK to get 3-epoch (4-yr) time series
===========================================

The key user-specific controls for this step (also incorporated in the :program:`sh_glred` runs within each year) are the list of sites to be used in defining the reference frame, and the *a priori* coordinates for these sites.
Here we use the same sites and coordinate file (:file:`igb14_comb.apr`) as in the single-year solutions, but this may not always be the case.
For the multi-year repeatabilities, we will use the combined H-files (:file:`.GLX`) created in the year :file:`gsoln/` directories.
So create a solution directory at the top level

.. code-block:: console

   $ mkdir vsoln

then change to the new directory and create a list of combined h-files for :program:`globk`:

.. code-block:: console

   $ cd vsoln
   $ ls ../????/gsoln/H*GLX > eura.gdl

Also copy the default template :file:`globk.cmd` and :file:`glorg.cmd` files to this directory, either using the same :console:`sh_glred -cmd`, as before, or directly from :file:`~/gg/tables/`.
For large or complex data sets, it's helpful at this point to run :program:`glist` which will check for blunders and give you a list of all the sites used and their spans.
Program :program:`glist2cmd` can then be helpful in establishing a :content:`use_site` list.
It may also be desirable to aggregate the data within each year, both to save time in the multi-year combination and to provide more representative long-term statistics.
The procedure for doing this is given in the file `sGPS_recipe.txt <http://geoweb.mit.edu/gg/courses/202303_GAGE-SAGE/examples/survey/sGPS_recipe.txt>`_ in the documentation directory on the web site.

.. code-block:: console

   $ rm globk_replong.org globk_replong.log
   $ glred 6 globk_replong.prt globk_replong.log eura.gdl globk.cmd >& glred.out

Unlike in :program:`sh_glred`, the :command:`rm` command may be needed here since :program:`glred` will concatenate the new :file:`.log` and :file:`.org` files with any previous files of the same name.
The :file:`globk_replong.prt` will not be created since we have set :content:`prt_opt NOPR` in :file:`globk.cmd`.