Index: /issm/trunk-jpl/src/m/plot/plot_unit.py
===================================================================
--- /issm/trunk-jpl/src/m/plot/plot_unit.py	(revision 17952)
+++ /issm/trunk-jpl/src/m/plot/plot_unit.py	(revision 17953)
@@ -42,5 +42,8 @@
 	   lims=options.getfieldvalue('caxis',[min(data),max(data)])
 	else:
-	   lims=[min(data),max(data)]
+		if min(data)==max(data):
+			lims=[min(data)-0.5,max(data)+0.5]
+		else:
+			lims=[min(data),max(data)]
 	norm = mpl.colors.Normalize(vmin=lims[0], vmax=lims[1])
 	if datatype==1:
Index: /issm/trunk-jpl/src/m/plot/processdata.py
===================================================================
--- /issm/trunk-jpl/src/m/plot/processdata.py	(revision 17952)
+++ /issm/trunk-jpl/src/m/plot/processdata.py	(revision 17953)
@@ -45,8 +45,14 @@
 	nanfill=options.getfieldvalue('nan',-9999)
 	if npy.any(npy.isnan(procdata)):
+		lb=npy.min(data[~npy.isnan(data)])
+		ub=npy.max(data[~npy.isnan(data)])
+		if lb==ub:
+			lb=lb-0.5
+			ub=ub+0.5
+			nanfill=lb-1
 		procdata[npy.isnan(procdata)]=nanfill
+		options.addfielddefault('clim',[lb,ub])
 		options.addfielddefault('cmap_set_under','1')
-		options.addfielddefault('clim',[npy.min(data[~npy.isnan(data)]),npy.max(data[~npy.isnan(data)])])
-		print "WARNING: nan's treated as -9999 by default.  Change using pairoption 'nan',nan_fill_value in plotmodel call"
+		print "WARNING: nan's treated as", nanfill, "by default.  Change using pairoption 'nan',nan_fill_value in plotmodel call"
 
 	#non-patch processing