[Gdal-dev] GDAL, JPIP and OpenEV

[Norman Barker]

-----Original Message-----
From: fwarmerdam at gmail.com [mailto:fwarmerdam at gmail.com]On Behalf Of
Frank Warmerdam
Sent: Wednesday, January 11, 2006 3:20 PM
To: Norman Barker
Cc: gdal-dev at lists.maptools.org
Subject: Re: [Gdal-dev] GDAL, JPIP and OpenEV


On 1/11/06, Norman Barker <nbarker at rsinc.com> wrote:
> Hi,
>
> just by chance when I was using OpenEV I noticed that when displaying ECW or Jpeg2000 it seems to have a progressive quality display.
>
> If OpenEV does implement progressive display for wavelet based images (with quality and resolution layers) how hard would it be for OpenEV to take its data from a JPIP server?
>
> I have a JPIP image server, and will have a go with OpenEV and GDAL if someone can confirm that I haven't witnessed a trick of the eye!!

Norman,

I believe it was a trick of the eye.  In particular as
you zoom in OpenEV will interpolate up the lower
resolution data till it has a chance to reload higher
resolution data.  So you are seeing full res data filled
in over time, but it isn't due to use of progressive display
from the wavelet information.  The same thing happens
with uncompressed formats.

I have had a little success in the past with GDAL
and JPIP via the JP2KAK driver but also lots of
unexplained failures.  Also, the JPIP in GDAL is only
supported on windows.  But I think you should be able to
use a jpip url with gdal (or openev) on win32 currently.

Best regards,
--
Hi Frank,

thanks for the answer, I will get my eyes checked :-)!

Is is possible that you could explain how to use a URL such as jpip://149.171.92.175/meteora.jp2 (which I grabbed from the Kakadu website) with GDAL and OpenEV please?

Since OpenEV implements a display mechanism of rendering the data with a time phase, could it be easily adapted to progressive display?

Many thanks,

Norman