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

[Juan Lucas Dominguez Rubio]

Hello, Simon:
 
- If I remember it well, the gdal you get by using apt-get or similar does not include the ECW compressor, but I think the binaries from the FWTools website do, though I cannot test it right now:
 
http://home.gdal.org/fwtools/FWTools-linux-2.0.6.tar.gz
 
Your experience suggests otherwise? Which error message do you get when trying to create a ECW?
 
- Your JPG files should come with a WLD or JPW (or similar) text file with at least six lines. If the second and third lines are NOT zero, you need to convert them in two steps:
 
gdalwarp -r cubic image.jpg image.tif
gdal_translate -of ecw image.tif image.ecw
 
If they are zero, you only need one step:
 
gdal_translate -of ecw image.jpg image.ecw
 
- Have you tried compressed TIF?
 
gdal_translate -co "COMPRESS=JPEG" image.jpg image.tif
 
 
Regards,
Juan Lucas Domínguez Rubio
---
Prodevelop SL, Valencia (España)
Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
http://www.prodevelop.es <http://www.prodevelop.es/> 
---

________________________________

De: gvsig_internacional-bounces at listserv.gva.es en nombre de Simon Cropper (Botanicus Australia Pty Ltd)
Enviado el: mar 14/09/2010 9:07
Para: Users and Developers mailing list
Asunto: [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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