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Posted to user@commons.apache.org by Gary Lucas <gw...@sonalysts.com> on 2011/07/26 14:44:14 UTC

[sanselan] Question about loading a partial image

I have a question about loading partial images using Sanselan.

I am using Sanselan to load and process GeoTIFF images and so far it works like a champ.   Unfortunately, some of the source files I'm using are quite large (12000x4000 pixels). When I "zoom in" to the image, the part that I am showing on my display is often much smaller (1000x1000 pixels).   Is there a means to load up a partial image?  I would like to accomplish too goals:

a) Loading time is about 6 seconds, which is a long time for a user to have to wait.  It would be nice to load a partial image and save loading time.

b) The buffered image produced by Sanselan when loading the file uses one 4-byte int per pixel, which is really convenient for my processing, but has the consequence that the memory use for the raw pixels is about 183 meg.  Loading a partial would reduce this.

The other thing I'm looking at is cases where I am "zoomed out".  It would be useful to copy the raw image to a reduced size using image processing built into Sanselan.  Do you have a code sample that shows how to do that.

Gary




Computer Programming is the Art of the Possible
Gary W. Lucas
Sonalysts, Inc.
215 Parkway North
Waterford, CT 06385
41-22-12.35 N / 72-10-07.54 E  (USNG/MGRS:  43T BF 63213 83711)



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