plotting.geodetic.gnss_fits: fix VR histogram, test for VR spread

beat/plotting/geodetic.py

@@ -373,14 +373,25 @@ def gnss_fits(problem, stage, plot_options):
 
  # get resulting bounds no plotting
  vmin, vmax = var_reductions_ens.min(), var_reductions_ens.max()
+ vspread = num.abs(vmax - vmin)
+ if vspread < 1e-4:
+ logger.warning(
+ "Spread in Variance Reduction is too small: %f, "
+ "skipping histogram plot!" % vspread
+ )
+ figs.append(m)
+ continue
+ # axis bounds
  imin, imax, sinc = get_nice_plot_bounds(vmin, vmax)
- nbins = 50
+ # hist bins
  Z = 0
 
  out_filename = "/tmp/histbounds.txt"
+ in_rows = num.atleast_2d(all_var_reductions[dataset.component]).T
+
  m.gmt.pshistogram(
- in_rows=num.atleast_2d(all_var_reductions[dataset.component]).T,
- W=(imax - imin) / nbins,
+ in_rows=in_rows,
+ W=1.5,
  out_filename=out_filename,
  Z=Z,
  I="o",
@@ -403,8 +414,8 @@ def gnss_fits(problem, stage, plot_options):
  ] + jxyr
 
  m.gmt.pshistogram(
- in_rows=num.atleast_2d(all_var_reductions[dataset.component]),
- W=(imax - imin) / nbins,
+ in_rows=in_rows,
+ W=1.5,
  G="lightorange",
  Z=Z,
  F=True,