maths formatting for low_tan

wellpathpy/tan.py

@@ -84,7 +84,7 @@ def high_tan(md, inc, azi):
     Notes
     -----
     Formulae:
-    
+
     .. math::
         northing = \sum (md_l - md_u) \cdot sin(inc_l) \cdot cos(azi_l)
 
@@ -111,31 +111,42 @@ def high_tan(md, inc, azi):
     return tan_method(md, inc, azi, choice='high')
 
 def low_tan(md, inc, azi):
-    """
-    Calculate TVD using low tangential method.
+    """Calculate TVD using low tangential method.
+
     This method takes the sines and cosines of the inclination and azimuth
     at the top of the survey interval to estimate tvd.
 
     This method is not recommended as it can make gross tvd and offset
     errors in typical deviated wells.
 
-    Formula
-    -------
-    northing = sum((md_lower - md_upper) * sin(inc_upper) * cos(azi_upper))
-    easting = sum((md_lower - md_upper) * sin(inc_upper) * sin(azi_upper))
-    tvd = sum((md_lower - md_upper) * cos(azi_upper))
-
-    where:
-    md_upper: upper survey station depth MD
-    md_lower: lower survey station depth MD
-    inc_upper: upper survey station inclination in degrees
-    azi_upper: upper survey station azimuth in degrees
-
     Parameters
     ----------
-    md: float, measured depth in m or ft
-    inc: float, well deviation in degrees
-    azi: float, well azimuth in degrees
+    md : float
+        measured depth
+    inc : float
+        well deviation in degrees
+    azi : float
+        well azimuth in degrees
+
+
+    Notes
+    -----
+    Formulae:
+
+    .. math::
+        northing = \sum (md_l - md_u) \cdot sin(inc_u) \cdot cos(azi_u)
+
+    .. math::
+        easting = \sum (md_l - md_u) \cdot sin(inc_u) \cdot sin(azi_u)
+
+    .. math::
+        tvd = \sum (md_l - md_u) \cdot cos(azi_u)
+
+    where:
+    :math:`md_u`: upper survey station depth MD
+    :math:`md_l`: lower survey station depth MD
+    :math:`inc_u`: upper survey station inclination in degrees
+    :math:`azi_u`: upper survey station azimuth in degrees
 
     Returns
     -------