I have multiple large rasters. Their 5 percentile and 95 percentile are needed to be calculated. After loading the rasters to the ArcMap, I am using the following codes - import numpy import arcpy rasters = ["raster1.tif", "raster2.tif", "raster3.tif", "raster4.tif"] for i in rasters: array = arcpy.RasterToNumPyArray(i,nodata_to_value=10000000000) marray = numpy.ma.masked_values(array,10000000000) del array percentile5 = numpy.percentile(marray.compressed(),(5)) percentile95 = numpy.percentile(marray.compressed(),(95)) del marray print percentile5 , percentile95 For the first two rasters, it provides the percentile values. For the third raster, it is showing memory errors as provided below. Traceback (most recent call last): File "E:\test\Stat\Inlinear data.py", line 89, in <module> marray = numpy.ma.masked_values(array,10000000000) File "C:\Python27\ArcGIS10.5\lib\site-packages\numpy\ma\core.py", line 2200, in masked_values condition = umath.less_equal(mabs(xnew - value), atol + rtol * mabs(value)) MemoryError Failed to execute (IntelinAir). I am using ArcMap 10.5 in desktop with 32 GB Ram. Is there any way to get rid of this memory issue?