There are many reasons this could be the case – a few most likely scenarios would be:
- Your AOI was partly cloudy this day. If clouds blocked our view of the ground where detections would have taken place, our feeds will not be able to detect anything
- Your AOI was completely cloudy. If clouds completely blocked out your area of interest, Planet might not publish the imagery. If there is no published imagery, there can be no detections.
There was nothing to detect. It could be that although we had a clear shot of the area, there were no objects to detect this day