Redo Sounding.find_el() with Series.intersect()

lib/xmet/series.py

@@ -13,13 +13,17 @@ class Series(dict):
     def __init__(self):
         super().__init__()
 
-    def intersect(self, series: Self, intersection: SeriesIntersection) -> tuple[float]:
+    def intersect(self, series: Self, intersection: SeriesIntersection, start: float=None) -> tuple[float]:
         pairs = nearest(sorted(self.keys(),   reverse=True),
                         sorted(series.keys(), reverse=True))
 
         for pair in pairs:
             v1, v2 = self[pair[0]], series[pair[1]]
 
+            if start is not None:
+                if pair[0] > start:
+                    continue
+
             sign = cmp(v1, v2)
 
             if sign == intersection.value:

lib/xmet/sounding.py

@@ -185,11 +185,6 @@ class Sounding(DatabaseTable):
 
         return series
 
-    def find_el(self, temp: float, pressure: float, temp_line: Series) -> tuple[float]:
-        moist_adiabat = follow_moist_adiabat(temp, pressure)
-
-        return moist_adiabat.intersect(temp_line, SeriesIntersection.LESSER)
-
     def derive_parameters(self) -> SoundingParameters:
         temp_line   = self.follow_temp()
         dry_adiabat = follow_dry_adiabat(self.samples[0].temp,
@@ -203,7 +198,7 @@ class Sounding(DatabaseTable):
         moist_adiabat = follow_moist_adiabat(*lcl)
 
         lfc = moist_adiabat.intersect(temp_line, SeriesIntersection.GREATER)
-        el  = self.find_el(lfc[0], lfc[1], temp_line)
+        el =  moist_adiabat.intersect(temp_line, SeriesIntersection.LESSER, lfc[1])
 
         params = SoundingParameters()
         params.lcl = lcl