time-aware composite mosaic dataset and MaxPS

Discussion created by ncurri on May 26, 2014
Latest reply on May 27, 2014 by hlzhang1022

I am creating a composite mosaic dataset from three other mosaic datasets, each of which holds four orthophoto tiles from different years: 2004, 2009, and 2013. The goal was to create a time-aware layer and use the time slider to demonstrate this functionality for my students. The extent of the tiles are the same across years and the coordinate system is all state plane (feet), the only difference between the datasets is that the 2009 photos are higher resolution (0.5 ft) than the 2004 and 2013 (1 ft). After I combine the mosaic datasets into the master mosaic dataset and enable time on the layer, ArcMap does not display the 2009 set when the time slider comes to that year. It's footprint appears, but nothing else, and the other two years display just fine.

At first, I tried using "build overviews" to see if that would fix it. It didn't. Then, I looked at the master mosaic dataset's footprint layer. I noticed that identical values are produced for MinPS, MaxPS, LowPS, and HighPS for the 2004 and 2013 sets in the master dataset's footprint attribute table. The LowPS for the 2009 orthos is (expectedly) 0.5, reflecting the higher resolution of this series. However, the MaxPS value is set to 1 for the 2009 set, while for the 2004 and 2013 sets the MaxPS value is 270.(Please see attached screenshot of the attribute table showing.)


I still wasn't quite sure what the MaxPS field does even after reading the help article on cell size ranges, but I changed it to 270 for the 2009 set, as it was set for the 2004 and 2013 sets, and then it displayed. In order to understand this better, I kept changing the value until I discovered that the image would appear if I set the value to 6 or greater. When set to 5 or less, the image would not appear when moving the time slider to 2009. I would LOVE it if someone can explain to me why so that I can explain it to my students!