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Thanks everyone.<br>
<br>
I got the message "GeoTiff is the preferred alternative file
format to ECW and gdal on Windows the method of converting the ECW
to GeoTiff".<br>
<br>
It's lucky I still have access to a Windows machine <span
class="moz-smiley-s5"><span> :-D </span></span> but wonder what
I would do if I only had access to Linux <span
class="moz-smiley-s7"><span> :-\ </span></span><br>
<br>
Again, thanks for the timely responses<br>
<br>
On 05/08/15 07:29, Enrique wrote:<br>
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<blockquote
cite="mid:CADPrcj71Mb1fVvoTXtRjRbxk=UnjorQw51LiKEg+9qh_aGuMXA@mail.gmail.com"
type="cite">
<div dir="ltr">As recommended by Paul Ramsey, tiled schema is a
better option, so I add it to gdal_translate command.<br>
<br>
Thanks!<br>
<br>
<br>
a. Reading ECW and compressing to JPG (set your favourite
quality, 80 is a good choice for orthoimages; also CACHEMAX
could be increased):<br>
<br>
gdal_translate --config GDAL_CACHEMAX 1000 --config
GDAL_PAM_ENABLED NO -of GTIFF -co COMPRESS=JPEG -co TILED=YES
-co JPEG_QUALITY=80 -co PHOTOMETRIC=YCBCR "source_image.ecw"
"target_image.tif"<br>
<br>
b. Adding internal pyramids/overviews with JPG compression
(select your resampling method, I prefer average):<br>
<br>
gdaladdo --config COMPRESS_OVERVIEW JPEG --config
PHOTOMETRIC_OVERVIEW YCBCR --config INTERLEAVE_OVERVIEW PIXEL -r
average "image.tif" 2 4 8 16 32 64 128<br>
<br>
<div class="gmail_extra"><br>
<div class="gmail_quote">2015-08-04 17:23 GMT+02:00 Steve
Golden <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:stevenlgolden@gmail.com" target="_blank">stevenlgolden@gmail.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">If you
have access to Windows XP and can install GDAL,
gdal_translate is the<br>
way to go to convert ECW to something else and GeoTIFF
should be on your<br>
list for that something else. There are a lot of webpages
out there with<br>
sample gdal_translate commands, but I recommend reading
about GeoTIFF<br>
compression<br>
<<a moz-do-not-send="true"
href="http://blog.cleverelephant.ca/2015/02/geotiff-compression-for-dummies.html"
rel="noreferrer" target="_blank">http://blog.cleverelephant.ca/2015/02/geotiff-compression-for-dummies.html</a>><br>
from a very good source.<br>
<br>
-Steve<br>
<br>
<br>
<br>
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<br>
<div class="moz-signature">-- <br>
Cheers Simon<span style="padding:1cm; font-family: sans-serif;
font-size:150%; "></span><span style="padding:1cm"></span><br>
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