I am running a Python script to make point feature layer from a series of netCDF files and then perform a spatial join with a number of polygons and save the results as a table. I am using arcpy.MakeNetCDFFeatureLayer_md and address its output to a variable in 'in_memory' workspace. My problem is that even though I am deleting the 'in_memory' after each loop using arcpy.Delete_management('in_memory'), it does not free up my RAM and after a couple of iterations I run into Memory Error. The function that is being called for each netCDF file looks like this:

def spatialJoin(nc):
    arcpy.env.overwriteOutput = True
    arcpy.env.workspace = 'in_memory'
    arcpy.MakeNetCDFFeatureLayer_md(nc, "SM", "lon", "lat", "SMPoints", "time;lat;lon", "", "", "", "BY_VALUE")

    <does the spatial join>

    print arcpy.Exists('SMPoints')
    print arcpy.Exists('SMPoints')

And the console prints:


for each iteration, which means Delete_management is working. But checking the python process in windows task manager shows that the data is piling up in RAM! I have tried deleting individual features inside 'in_memory' as well as deleting the whole 'in_memory' but nothing seems to work. Am I missing something here?

P.S. Spatial join does not affect the problem here, problem exists even when I completely comment out the spatial join section.

  • It's nasty, but you could try and delete the arcpy module import after each iteration then re import it. Commented Aug 20, 2016 at 0:34
  • 1
    Did you see gis.stackexchange.com/questions/19684/…? Also it's worthwhile to have a look at geeohspatial.blogspot.com.au/2013/12/…
    – fatih_dur
    Commented Aug 20, 2016 at 3:29
  • Thanks @fatih_dur, the second link was useful. I managed to free up the memory by using multiprocessing module. It slowed down the process a bit, but the memory leak has stopped ;)
    – Monobakht
    Commented Aug 20, 2016 at 11:59

1 Answer 1


You shouldn't need to set your environment workspace to in_memory as you are doing in your script, so you can drop this line:

arcpy.env.workspace = 'in_memory'

Also, ensure that you are using double-quotes when referencing your in_memory workspace inside of the geoprocessing tool.

  • 3
    "ensure that you are using double-quotes when referencing your in_memory workspace" - that's a new one for me, can you explain/reference the double-quotes requirement over single-quotes?
    – Midavalo
    Commented Aug 19, 2016 at 21:12
  • Thanks @Radar, but changing to double-quote didn't help!
    – Monobakht
    Commented Aug 20, 2016 at 11:55

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