==============

usage: quick_adcp.py, user chooses

   --ref_method: ("smoothr", old method) implies "putnav":
                       - no automated xducerxy support
                       - uses "fixfile" to calculate ship speeds

                 ("refsm", default) implies put_tuv, put_txy 

       - navigation: position file depends on values of xducer_dx,xducer_dy

       - ship velocities: 
            - choose source
                --refuv_source 'navigation'  # (get shipuv with first diffs)
                --refuv_source 'uvship'      # (comes from uvship file)
    
            -  specify amount of smoothing
                --ref_smoothwin 3 [2,1,0]    # default is 3, bl_filt_halfwin

==============

what happens:

quick_adcp.py --steps2rerun navsteps

       means 
         (1) adcpsect, refabs, smoothr, putnav, reflayer pictures
         (2) reflayer smoothing:
                 (choose ref_method 'refsm'  or 'smoothr')

--ref_method smoothr
        fixfile --> (smoothr) --> refsm.sm --> (putnav) --> database
        positions come from smoothr output, shipspeeds are calculated from nav

--ref_method refsm (default)
        positions: fixfile --> (xducer_dx, xducer_dy) --> txy_file --> (put_txy) --> database
                               

        ship speeds: 
              "--refuv_source"
              if method is 'nav'    (use txy_file --> refuv.asc), then put_tuv --> database
              if method is 'uvship' (use  uvship  --> refuv.asc), then put_tuv --> database


xducer_dx, xducer_dy:

txy_file is:
         singleping         dbinfo  postprocessing
         0,0  (load/*gps2)  0,0     nav/aship.gps 
         X,Y  (load/*gpst2) X,Y     nav/aship.agt 


         but always gps        +(XY) --> agt
                (i.e. fixfile) +(XY) --> agt


pingdata must use smoothr
smoothr cannot use xducer_dx, xducer_dy
tuv_file is always refuv_tuv.asc (depends on "refuv_source"  and "refuv_smoothwin")

=================================

dbinfo:      --ref_method smoothr
-------
         refuv_smoothwin   None
            refuv_source   None
            txy_file   None   # unspecified, since putnav is used
           xducer_dx   None   # unspecified, not allowed with smoothr
           xducer_dy   None   # unspecified, not allowed with smoothr


dbinfo:    --ref_method refsm   
------

--ref_source nav

        refuv_source   nav      # put_tuv file "refsm.asc" from nav

--ref_source uvship

        refuv_source   uvship   # put_tuv file "refsm.asc" from uvship file

=========

--xducer_dx 0 --xducer_dy 0

            txy_file   aship.gps
           xducer_dx   0
           xducer_dy   0


--xducer_dx 1 --xducer_dy -36

            txy_file   aship.agt # positions shifted from aship.gps
           xducer_dx   1
           xducer_dy   -36