another purge criterion

src/Model/Geometry/PointXYZ.py

@@ -230,6 +230,7 @@ class PointXYZ(Point, SQLSubModel):
         c = PointXYZ.distance(p1, p3)
         return acos((a**2 + b**2 - c**2) / (2 * a * b))
 
+
     @staticmethod
     def triangle_height(p1, p2, p3):
         """triangle p1 p2 p3 height starting at p2.
@@ -247,3 +248,19 @@ class PointXYZ(Point, SQLSubModel):
         c = PointXYZ.distance(p1, p3)
         h2 = a**2 - ((c**2 - b**2 + a**2) / 2*c)**2
         return sqrt(h2)
+
+    @staticmethod
+    def triangle_area(p1, p2, p3):
+        """triangle p1 p2 p3 area.
+
+        Args:
+            p1: A XYZ Point
+            p2: A XYZ Point
+            p3: A XYZ Point
+
+        Returns:
+            triangle height starting at p2
+        """
+        h = PointXYZ.triangle_height(p1, p2, p3)
+        d = PointXYZ.distance(p1, p3)
+        return h*d/2

src/Model/Geometry/ProfileXYZ.py

@@ -435,7 +435,7 @@ class ProfileXYZ(Profile, SQLSubModel):
         return lcum
 
     @timer
-    def purge(self, np) -> list:
+    def purge1(self, np) -> list:
 
         points = self.points
         if (self.number_points <= np): return points
@@ -464,6 +464,20 @@ class ProfileXYZ(Profile, SQLSubModel):
 
         return points
 
+    @timer
+    def purge3(self, np) -> list:
+
+        points = self.points
+        if (self.number_points <= np): return points
+        while len(points) > np:
+            l2 = []
+            for i in range(len(points)-2)
+                l2.append(PointXYZ.triangle_area(points(i),points(i+1),points(i+2)))
+            imin = np.argmin(l2)+1
+            points.pop(imin)
+
+        return points
+