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Python script to calculate NDVI anomalies.

Question asked by vianna on Jun 7, 2018
Latest reply on Jun 14, 2018 by vianna

Why the last line of this code is not working? It is the line of "Minus_3d" calculation?

 

This is a python script to calculate NDVI anomalies.

 

Thanks.

 

# Import arcpy module
import arcpy
from arcpy import env
from arcpy.sa import *
arcpy.env.overwriteOutput = True

# Check out any necessary licenses
arcpy.CheckOutExtension("spatial")

#Define workspaces
arcpy.env.workspace="D:\\Modis250\\NDVI_10dias_norm" #Workspace with decendial (ten days period) NDVI
#Filenames standard is "norm_ndvi_yyyy_dec_d.tif" where "yyyy" is the year and "d" is the ten days period: d=1 = january 1-10; d=2 = january 11-20; ...

for n in range (1,37):
d=str(1)
y = str(2004)
NDVINormAll=arcpy.ListRasters("norm_ndvi_*_"+d+".tif", "tif")#List of decendial NDVI for all years to calculate the dcendial mean
NDVINormY=arcpy.ListRasters("norm_ndvi_"+y+"_dec_"+d+".tif", "tif")#List of decendial NDVI rasters for the last year (y)
NDVIMeanOut = "D:\\Modis250\\NDVI_10dias_mean\\"+"mean_dec_"+d+".tif" #Define the decendial NDVI mean output (could be temporary)
NDVIMean = arcpy.gp.CellStatistics_sa(NDVINormAll, NDVIMeanOut,"MEAN", "NODATA")#Calculate the decendial NDVI mean (could be temporary)
NDVIAnomOut = "D:\\Modis250\\NDVI_10dias_anom\\"+"anom_"+y+"_dec_"+d+".tif" #Define the last year decendial NDVI anomaly output
NDVIAnom=arcpy.gp.Minus_3d(NDVINormY, NDVIMean, NDVIAnomOut) #Calculate the last year decendial NDVI anomaly and record the output tifs
print ("Decade "+d+" of "+y+" ok")

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