Which of the following is an example of a zonal function?
1) Applying a conditional operation to a grid cell within a 3x3 moving window.
2) Calculating the mean NDVI value within a 9x9 moving window of grid cells.
3) Calculating the deviation from a global mean temperature value at each grid cell within a raster dataset.
4) Calculating the total population within a county based on an ambient population raster dataset such as LandScan.