I just found an article that Fredrik wrote based on a discussion we had on memory limits back in 1999. Using the .tile attribute and doing your work in chunks is one sure-fire way of getting there, although it'll take some effort. I hope this helps!
http://effbot.org/zone/pil-large-images.htm Kevin. On Sep 8, 2011, at 7:07 AM, Craig Coleman (C) wrote: > Hi, > > I have a really thorny problem. > > I need to downsample a raster map that is 23622x23622 pixels to 7874x7874 > pixels using the ANTIALIAS filter. > > I have the following Python code: > > >>> import Image > >>> img = Image.open(r"C:\temp\24bit_nd.tif") > >>> nimg = img.resize((7874,7874),Image.ANTIALIAS) > > As soon as the resize method is called, python crashes instantly. I presume > this is a memory allocation issue. > > Is there another way of performing anti-aliasing on such a large image (its > 2.7GB uncompressed although I'm using LZW for storage). > > I have tried converting the file to 8bit with a palette and this successfully > downsamples but the ANTIALIAS is not performed. What am I doing wrong? > > Craig Coleman > Technical Lead > Information Systems, Ordnance Survey > L0F2, Adanac Drive, SOUTHAMPTON, United Kingdom, SO16 0AS > Phone: +44 (0) 2380 054641 > www.ordnancesurvey.co.uk | craig.cole...@ordnancesurvey.co.uk > Please consider your environmental responsibility before printing this email. > > This email is only intended for the person to whom it is addressed and may > contain confidential information. If you have received this email in error, > please notify the sender and delete this email which must not be copied, > distributed or disclosed to any other person. > > Unless stated otherwise, the contents of this email are personal to the > writer and do not represent the official view of Ordnance Survey. Nor can any > contract be formed on Ordnance Survey's behalf via email. We reserve the > right to monitor emails and attachments without prior notice. > > Thank you for your cooperation. > > Ordnance Survey > Adanac Drive > Southampton SO16 0AS > Tel: 08456 050505 > http://www.ordnancesurvey.co.uk > > _______________________________________________ > Image-SIG maillist - Image-SIG@python.org > http://mail.python.org/mailman/listinfo/image-sig
_______________________________________________ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
