bug in label

app.py

@@ -361,7 +361,7 @@ def generate_climb_profile(df_hill: pd.DataFrame, title: str):
         .mark_area()
         .encode(
             x=alt.X("distance_from_start")
-            .axis(grid=False, tickCount=10, labelExpr="datum.label + ' km'", title=None)
+            .axis(grid=False, tickCount=10, labelExpr="datum.label + ' m'", title=None)
             .scale(domain=(0, df_hill["distance_from_start"].max())),
             y=alt.Y("elev").axis(
                 domain=False,
@@ -500,7 +500,7 @@ if gpx_file is not None:
             index=pd.Index(np.arange(0, df_hill["distance_from_start"].max(), 10))
         )
         df_hill_resample = pd.concat(
-            [df_hill.set_index("distance_from_start"), df_new_index], axis=1
+            [df_hill.set_index("distance_from_start"), df_new_index], axis=0
         ).sort_index()
         df_hill_resample = df_hill_resample[["elev", "grade"]].interpolate()
         df_hill_resample["color_grade"] = df_hill_resample["grade"].map(grade_to_color)