[Gvsig_english] QUESTION gvSIG -- Image files with fast rewrites

[Rahkonen Jukka]

Hi,
 
I would guess that JPEG compressed tiled tiff files might work fine.  They are not necessarily understood by all software but GDAL reads and writes them fine.
Read http://gdal.org/frmt_gtiff.html
Use creation option TILED=YES, COMPRESS=JPEG and PHOTOMETRIC=YCBCR.  Fine tuning can be done with JPEG_QUALITY. 
 
-Jukka Rahkonen-
 


________________________________

	Lähettäjä: gvsig_internacional-bounces at listserv.gva.es [mailto:gvsig_internacional-bounces at listserv.gva.es] Puolesta Simon Cropper (Botanicus Australia Pty Ltd)
	Lähetetty: 14. syyskuuta 2010 10:08
	Vastaanottaja: Users and Developers mailing list
	Aihe: [Gvsig_english] QUESTION gvSIG -- Image files with fast rewrites
	
	

	Hi,
	
	Most of my clients provide aerial photography in ECW format. These images provide high resolution, are relatively small and quickly rewrite on the screen when panning.

	

	Lately I have been getting JPG files. These files however are quite big and take significantly longer time to rewrite.

	

	What is an alternative image format to ECW in the 'open free' environment? Something GDAL can be used to convert from JPG without jumping through hoops.

	

	Ideally the file sizes should be low despite the high resolution, gvSIG able to read it natively and is quick to rewrite when panning.

	

	Any suggestions would be appreciated.

	

	PS. I know gdal_translate can, supposedly convert between JPG and ECW, but despite many attempts I have been unable to get this to work. I am looking for something else, if possible, that has the same intrinsic properties but is recognized by default in the gdal libraries so that every time I get an update of the 'free' Ubuntu version the FWTools or alternative 'commercially enabled' version is not replaced.
	

	-- 
	Cheers Simon

	Simon Cropper 
	Botanicus Australia Pty Ltd
	PO Box 160, Sunshine, Victoria 3020.
	P: 9311 5822. M: 041 830 3437.
	mailto: scropper at botanicusaustralia.com.au <mailto:scropper at botanicusaustralia.com.au>  
	web: www.botanicusaustralia.com.au <http://www.botanicusaustralia.com.au>  

	

	(C) Simon Cropper 2010. Creative Commons Attribution-ShareAlike 3.0 Australia
	

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