Still needs more work for GPS info. The NMEA strings written on these
files don't seem to be complete.

This is to finalize the scripts for Hills et al. (2020) to be submitted
to the Radioglaciology Annals volume.
A total of 6 attenuation methods implemented:
Method 2 -- Jacobel et al. (2009)
Method 3 -- Schroeder et al. (2016a, 2016b)
Method 5 -- MacGregor et al. (2014); Matsuoka et al. (2010)
Method 6a -- Depth-resolved (regression similar to method 1)
Method 6b -- Depth-resolved (regression similar to method 3)
Method 7 -- Secondary reflection as in Christianson et al. (2016)

Accommodate multiple files and multiple bursts

Following Brennan et al. (2013) and Nicholls et al. (2015) calculate the
vertical motion using a moving window and correlation coefficient
calculated at subsequent depths in two acquisition profiles. Vertical
ice motion between acquisitions can be seen for both internal
reflections and the bed reflector.

Uses the correlation coefficient between two ApRES profiles to determine
the relative motion between acquisitions.

If the gps data onto which the interpolation will be done has longitude
notation different than the radar longitude, then raise an error. We
were having problems with one being written from 0 - 360 and the other
from -180 - 180.

Center the depth profile with each point now representing the center of
the window rather than the top.

There were too many options in the plot command which made it confusing.
I cut some out and hopefully made the help file more clear as to how one
could plot the spectral density for each trace using Joshua's function.

Following Kingslake et al. (2014) calculate uncertainty with a noise
phasor that has random phase and magnitude equal to the median of the
measured phasor.

Line to load the time step from the header file was looking for the time
window as 'WINDOW' when a later line has 'AMPLITUDE WINDOW' so it was
loading that number instead.

These files are mostly the same as the ImpDAR matlab files but commonly
have the data named as 'filtdata', 'interp_data', 'migdata', etc.

There were too many variables named similar things, so I made it a bit
more clear.

Removed 1e6 on the depth vector

This routine asks for some picked points on the left side of the image
and will spit out picks across the image for each.

The autopicker was not working nicely with the normal picker. That is,
when switching back and forth, the program would break. This was because
of an indexing issue with the pick number. Fixed.

…of .mat files, allow these to be loaded into ImpDAR

This is in regard to the adaptive horizontal filter. The scaling
function that is used to keep the filter from changing the deeper data
is much more complicated than what I would have used. Considering
simplifying.

This was overly complicated and different from that being used in hfilt.
I just copied from hfilt, and cleaned up some of the code. I also added
optionality for setting the window_size from the command line function.