Compressing map algebra outputs from ArcPy

Question

When creating a raster map algebra output, is it possible to set its compression? I'm creating a model which generates many hundreds of rasters, and currently each is being stored without any compression which quickly adds up. I expected to be able to use arcpy.env.compression but that seems to have no effect. Example script which produces this behavior:

import arcpy

arcpy.env.compression = 'LZW' # supported by GeoTIFF and most packages

map = Raster("raster.tif") + 100
map.save("raster_plus_100.tif") # would expect this output to have compresssion

Answer 1

I think the problem is that arcpy.env settings only apply to tools. Calling a method on an object is not technically a "tool". In a practical sense, the arcpy.env settings should apply to stuff like Raster.save() but it doesn't appear to work that way.

I was able to save a raster with compression by using arcpy.CopyRaster_management(). Something like this:

arcpy.env.compression = 'LZW'
t1 = arcpy.Raster('sample.tif') + 100
arcpy.CopyRaster_management(t1, 't1.tif')
del t1

Answer 2

Try using ApplyEnvironment on the raster variable.

#convert raster form meter to feet
raster = arcpy.Raster(raster_path) * 0.3048
arcpy.env.compression = 'LZW'
compressedRaster = arcpy.sa.ApplyEnvironment(raster)
compressedRaster.save(output_path)

Answer 3

I don't think it is what you are looking for, I think it if for unicode strings

>>> dir(arcpy.env.compression) ... ['__add__', '__class__', '__contains__', '__delattr__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__getslice__', '__gt__', '__hash__', '__init__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '_formatter_field_name_split', '_formatter_parser', 'capitalize', 'center', 'count', 'decode', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'islower', 'isnumeric', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']

Answer 4

I see a double quote in the online example...
arcpy.env.compression = "LZW"