Store probabilities as floats

db/xmet.sql

@@ -154,7 +154,8 @@ create table xmet_spc_outlook_probability_area (
     id          INTEGER PRIMARY KEY NOT NULL,
     outlook_id  INTEGER NOT NULL,
     hazard      TEXT NOT NULL,
-    probability INTEGER NOT NULL,
+    probability FLOAT,
+    sig         BOOLEAN NOT NULL DEFAULT FALSE,
 
     FOREIGN KEY (outlook_id) REFERENCES xmet_spc_outlook (id)
 );

lib/xmet/spc.py

@@ -112,14 +112,14 @@ class SPCOutlookArea(DatabaseTable):
 
 class SPCOutlookProbabilityArea(SPCOutlookArea):
     __slots__ = (
-        'hazard', 'probability',
+        'hazard', 'probability', 'sig',
     )
 
     __table__ = 'xmet_spc_outlook_probability_area'
     __key__   = 'id'
 
     __columns__ = (
-        'id', 'outlook_id', 'hazard', 'probability', 'poly'
+        'id', 'outlook_id', 'hazard', 'probability', 'sig', 'poly'
     )
 
 class SPCOutlookCategoryArea(SPCOutlookArea):
@@ -293,9 +293,15 @@ class SPCOutlookParser():
         for poly in each_poly(self.points):
             if self.area_type == 'PROBABILISTIC':
                 area = SPCOutlookProbabilityArea()
-                area.hazard      = self.hazard
-                area.probability = self.category
-                area.poly        = poly
+                area.hazard = self.hazard
+                area.poly   = poly
+
+                if self.category == 'SIGN':
+                    area.probability = None
+                    area.sig         = True
+                else:
+                    area.probability = float(self.category)
+                    area.sig         = False
 
                 self.outlook.probabilities.append(area)
             elif self.area_type == 'CATEGORICAL':