def create_new_grid(self):
    ' Create a new empty grid.'
    self.xx = np.arange(min(self._x), (max(self._x) + self.cs), self.cs)
    self.yy = np.arange(min(self._y), (max(self._y) + self.cs), self.cs)
    if (not (self.gridsizesanitycheck(self.xx) and self.gridsizesanitycheck(self.yy))):
        print('Grid size is too large.')
        return
    self.zw = np.empty((self.yy.size, self.xx.size))
    self.zw.fill(np.nan)
    self.nn = np.copy(self.zw)
    self.ww = np.copy(self.zw)
    self.varw = np.copy(self.zw)
Create a new empty grid.
def create_new_grid(self):
    ' '
    self.xx = np.arange(min(self._x), (max(self._x) + self.cs), self.cs)
    self.yy = np.arange(min(self._y), (max(self._y) + self.cs), self.cs)
    if (not (self.gridsizesanitycheck(self.xx) and self.gridsizesanitycheck(self.yy))):
        print('Grid size is too large.')
        return
    self.zw = np.empty((self.yy.size, self.xx.size))
    self.zw.fill(np.nan)
    self.nn = np.copy(self.zw)
    self.ww = np.copy(self.zw)
    self.varw = np.copy(self.zw)