diff --git a/bin/xmet-sounding-graph b/bin/xmet-sounding-graph
index 609de25..717316b 100755
--- a/bin/xmet-sounding-graph
+++ b/bin/xmet-sounding-graph
@@ -42,7 +42,7 @@ with cairo.SVGSurface(args.output, IMAGE_WIDTH, IMAGE_HEIGHT) as surface:
     cr.rectangle(0, 0, IMAGE_WIDTH, IMAGE_HEIGHT)
     cr.fill()
 
-    skew_t.draw(cr, 64, 64, sounding.samples)
+    skew_t.draw(cr, 64, 64, sounding)
 
     cr.set_source_rgb(0, 0, 0)
     cr.rectangle(64, 64, GRAPH_WIDTH, GRAPH_HEIGHT)
diff --git a/lib/xmet/hodograph.py b/lib/xmet/hodograph.py
index e2e4f64..48e0ace 100644
--- a/lib/xmet/hodograph.py
+++ b/lib/xmet/hodograph.py
@@ -1,10 +1,8 @@
 import math
 import cairo
 
-from typing import Iterable
-
 from xmet.igra     import IGRAReader
-from xmet.sounding import Sounding, SoundingSample
+from xmet.sounding import Sounding
 
 WIND_SPEED_MAX  = 100 # knots
 WIND_SPEED_MIN  =  10
@@ -123,11 +121,11 @@ class Hodograph():
             if height < key:
                 return self.COLORS[key]
 
-    def draw_samples(self,
-                     cr: cairo.Context,
-                     x,
-                     y,
-                     samples: Iterable[SoundingSample]):
+    def draw_sounding(self,
+                      cr: cairo.Context,
+                      x,
+                      y,
+                      sounding: Sounding):
         cr.save()
 
         first      = True
@@ -135,7 +133,7 @@ class Hodograph():
         sx_last    = None
         sy_last    = None
 
-        for sample in samples:
+        for sample in sounding.samples:
             if sample.pressure < 0 or sample.pressure is None:
                 continue
 
@@ -214,7 +212,7 @@ class Hodograph():
 
             offset += interval
 
-    def draw(self, cr: cairo.Context, x, y, samples: Iterable[SoundingSample]):
+    def draw(self, cr: cairo.Context, x, y, sounding: Sounding):
         cr.rectangle(x, y, self.width, self.height)
         cr.clip()
 
@@ -224,7 +222,7 @@ class Hodograph():
         self.draw_speed_lines(cr, x, y)
         self.draw_direction_lines(cr, x, y)
 
-        self.draw_samples(cr, x, y, samples)
+        self.draw_sounding(cr, x, y, sounding)
 
         self.draw_speed_legends(cr, x, y)
         self.draw_direction_legends(cr, x, y)
diff --git a/lib/xmet/skew_t.py b/lib/xmet/skew_t.py
index 29c54ab..c45adf0 100644
--- a/lib/xmet/skew_t.py
+++ b/lib/xmet/skew_t.py
@@ -1,9 +1,9 @@
 import math
 import cairo
 
-from typing import Iterable, Callable
+from typing import Callable
 
-from xmet.sounding import SoundingSample
+from xmet.sounding import Sounding
 
 PRESSURE_MAX  = 1050 # millibar
 PRESSURE_MIN  =  100
@@ -101,17 +101,17 @@ class SkewTGraph():
 
         cr.restore()
 
-    def draw_samples(self,
+    def draw_sounding(self,
                      cr: cairo.Context,
                      x: float,
                      y: float,
-                     samples: Iterable[SoundingSample],
+                     sounding: Sounding,
                      fn: Callable):
         cr.save()
 
         first = True
 
-        for sample in samples:
+        for sample in sounding.samples:
             if sample.pressure < 0 or sample.pressure is None:
                 continue
 
@@ -143,7 +143,7 @@ class SkewTGraph():
              cr: cairo.Context,
              x: float,
              y: float,
-             samples: Iterable[SoundingSample]):
+             sounding: Sounding):
         cr.rectangle(x, y, self.width, self.height)
         cr.clip()
 
@@ -151,10 +151,10 @@ class SkewTGraph():
         self.draw_isobars(cr, x, y)
 
         cr.set_source_rgb(1, 0, 0)
-        self.draw_samples(cr, x, y, samples, lambda s: s.temp)
+        self.draw_sounding(cr, x, y, sounding, lambda s: s.temp)
 
         cr.set_source_rgb(0, 1, 0)
-        self.draw_samples(cr, x, y, samples, lambda s: s.dewpoint)
+        self.draw_sounding(cr, x, y, sounding, lambda s: s.dewpoint)
 
         cr.reset_clip()