Changes coming in the way NASA data files are obtained

Our correlators, AIPS, and CASA have depended on CDDIS for data files
providing estimates of the location of Earth's North Pole (EOPS) and
also total electron content.  But changes are coming.  The CDDIS data
distribution site has made the following announcement:

"The Crustal Dynamics Data Information System (CDDIS) supports data
archiving and distribution activities for a global user community. Since
its inception, users have relied on anonymous ftp for accessing and
downloading files from the system. Although this protocol allows users
to easily automate file downloads, many organizations, data systems, and
users have already migrated from ftp or are actively pursuing a move
away from the protocol due to problems from a system and security
standpoint. U.S. Government agencies have become increasingly concerned
about this legacy protocol and ensuring data integrity for the user
community and have recently begun to disallow the use of the ftp
protocol. The CDDIS, located at NASA GSFC, must therefore address these
concerns and provide alternative methods for access to its archive for
continued easy and automated download of its contents."

Further text regarding this change, which will occur in October 2020, may
be found at
   https://cddis.nasa.gov/Data_and_Derived_Products/CDDIS_Archive_Access.html
This text suggests that users may have to have an Earthdata login
account as well as a .netrc file in their home disk directory.  This is
reasonable for our correlator systems, but ii is NOT convenient for the
1000's of users of AIPS and CASA data reduction systems.  Fortunately,
there appears to be a "curl" command which will work with the new
system.

AIPS has now changed VLAPROCS and VLBAUTIL in both the 31DEC20 and
31DEC19 versions, as well as a number of help files, to support the
changed access methods.  For the EOPS file, the command (all one 1
line!)

   curl -u anonymous:daip@nrao.edu --ftp-ssl ftp://gdc.cddis.eosdis.
      nasa.gov/vlbi/gsfc/ancillary/solve_apriori/usno_finals.erp
      > /tmp/usno_finals.erp

(no blanks between ancillary/ and solve) seems to work for VLBAEOPS.
For the TEC file, again on 1 line, the command
curl -u anonymous:daip@nrao.edu --ftp-ssl ftp://gdc.ccdis.eosdis.nasa.gov/
   gps/products/ionex/YYYY/DDD/jplgDDD0.YYi.Z > /tmp/jplgDDD0.YYi.Z

(no blanks between gov/ and gps) where YYYY is the year e.g. 2015, YY is
the last 2 digits of the year e.g. 15, and DDD is the day number within
the year.

Experienced users may note that the lower levels of the paths to these
files have not changed.  The upper level name and the -u and --ftp-ssl
are the necessary changes.

Note that running the MNJ ($HOME/do_daily.<hostname>) in either 31DEC20
or 31DEC19 will get the updated procedures and help files.  The new web
access method already works, although the old methods should also work
through September.