Add doc on orientation as tutorials

navipy/trajectories/__init__.py

@@ -382,18 +382,26 @@ class Trajectory(pd.DataFrame):
                 raise KeyError('df should contains q_2 or alpha_2')
         return self
 
-    def from_markers(self, markers, triangle_mode, error=None):
+    def from_markers(self, markers, triangle_mode,
+                     error=None, markers_labels=[0, 1, 2]):
+        indeces = markers.index
+        # Reinit the pandas dataframe super class
+        # because we now know the indeces
+        super().__init__(index=indeces, columns=self.columns, dtype=float)
+        # If error is provided, we can propagate the error
         if error is not None:
             self.trajectory_error = pd.DataFrame(data=np.nan,
                                                  index=self.index,
                                                  columns=self.columns)
-        mark0 = markers.loc[:, 0]
-        mark1 = markers.loc[:, 1]
-        mark2 = markers.loc[:, 2]
+        markers2use = markers.loc[:, markers_labels]
+        markers2use = markers2use.dropna()
+        mark0 = markers2use.loc[:, markers_labels[0]]
+        mark1 = markers2use.loc[:, markers_labels[1]]
+        mark2 = markers2use.loc[:, markers_labels[2]]
         x = np.zeros(9)  # 3points with x,y,z
         kwargs = {'triangle_mode': triangle_mode,
                   'euler_axes': self.rotation_mode}
-        for index_i in self.index:
+        for index_i in markers2use.index:
             # Assign mark to pos
             x[0:3] = mark0.loc[index_i, ['x', 'y', 'z']].values
             x[3:6] = mark1.loc[index_i, ['x', 'y', 'z']].values
@@ -420,6 +428,7 @@ class Trajectory(pd.DataFrame):
 
             self.loc[index_i, 'location'] = position
             self.loc[index_i, self.rotation_mode] = orientation
+        return self
 
     def world2body(self, markers):
         """ Transform markers in world coordinate to body coordinate