Issues found in code review

• Issue 1: grid_to_poly.ZonalSummary would not run when calc_nodata=False. I suggest adding an else statement at line 190 in grid_to_poly.py to set self.stats when calc_nodata is False.
• Issue 2: Percentile does not seem to be a stat that can be calculated in grid_to_poly.ZonalSummary
• Issue 3: grid_to_poly.ZonalSummary would not run without ‘count’ in the stats list while calc_nodata=False (after Issue 1 was fixed)