[Gvsig_english] Tiff image pyramid

[Simone Giannecchini]

Ciao Kami,
GeoTools handles geotiff pyramids  through JAI-ImageIO. We are
currently  extending JAI-ImageIO with the Imageio-ext (see
https://imageio-ext.dev.java.net/) to support new formats from GDAL,
hence as soon as 1.5.3 gets released we will start tagging a first
official release. Roughly speaking, we should have official releases
for imageio-ext within the end of the year (FYI, we are also building
support for JP2 through kakadu directly and we are also looking into
integrating support for ImageMagick).

I have not looked at the gvSIG codebase lately, even though I had an
interesting discussion with the gcSIG mobile developers as well as
with Victor Olaya (sextante) during the OSGEO codesprint in bolsena
about collaboration on the IO raster side of the gvSIG world. As far
as I know gvSIG should make use of the pyramids even though I am aware
of some limitation. However, gvSG developers should have more
information on this (feel also free to correct me if I am wrong).

Just out of curiosity, I think it would be great to try and
collaborate at the raster I/O level with the gvSIG team since what we
are doing is currently used in GeoServer, GeoTools and uDig and
widening the audience would be just great IMHO. I'll leave this up to
the gvSIG developers/PMs.


Ciao,
Simone.

--
-------------------------------------------------------
Eng. Simone Giannecchini
GeoSolutions S.A.S.
Owner - Software Engineer
Via Carignoni 51
55041  Camaiore (LU)
Italy

phone: +39 0584983027
fax:      +39 0584983027
mob:    +39 333 8128928


http://www.geo-solutions.it
http://www.geo-solutions.it/simone.giannecchini
http://www.linkedin.com/in/simonegiannecchini

-------------------------------------------------------



On Fri, Oct 10, 2008 at 6:13 AM, Kami ROUSSEAU <kamikulture at yahoo.ca> wrote:
> Hello,
>
> I have a tiff file that contains a full size 16Kx16K image, compressed using JPEG. The file also contains ten reduced size overviews. When this image is opened in gvSIG, the overviews are not used; instead, the full size image is red in memory. This reading operation takes a long time to complete.
>
> I know that Java Advanced Imaging (JAI) can handle image pyramids and that Geotools uses this capability. I also know that gdal can use image pyramids. Quantum GIS uses gdal to display an overview of the image.
>
> Is there an existing automatic or semi-automatic way to read an appropriately sized overview instead, using gvSIG / jgdal?
>
> If so, what is it?
> If not, what development would be necessary? What are the relevent libraries / classes? Is there any reading material that could help?
>
> Kami Rousseau
>
>
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