[Gdal-dev] GDALDataset as a Base Class

[Matt Hanson]

There are some roadblocks to combining these two libraries but I think I have a decent plan of attack.  Certainly some algorithms can't be processed piecewise, but many can.   The important thing is to properly pad out each chunk based on the size of the neighborhood (for neighborhood-based algorithms).   Some algorithms will require a different approach, such as an FFT which requires processing entire columns, then rows.
 
As far as OSSIM goes, to be perfectly honest I've attempted to use it on several occasions and every time I throw my hands up in despair.   I think I'm a fairly educated guy (i have an MS in Remote Sensing/Image Processing), but OSSIM is way beyond me.   It's true these things can be accomplished with OSSIM and I've been very impressed with what OSSIM can do, but I can't do them.   There is a severe lack of documentation and tutorials, mixed with the fact that the actual code is extremely confusing (to me).    Personally I think OSSIM has way too many classes whose interactions are mind-boggling, and lacks an easy to use API.    Obviously OSSIM has been used to do very cool things such as the ImageLinker and osgPlanetViewer apps but I feel more comfortable writing my own then trying to make sense of it.   It won't be as powerful as OSSIM but it will have a more intuitive interface.
 
 
matt
 
 
Matt Hanson
http://www.omnium-gatherum.org
 

________________________________

From: Ari Jolma [mailto:ari.jolma at tkk.fi]
Sent: Fri 9/1/2006 12:38 PM
To: Matt Hanson
Cc: gdal-dev at lists.maptools.org
Subject: Re: [Gdal-dev] GDALDataset as a Base Class



Matt Hanson kirjoitti:
> To clarify what I'm doing, I'm creating an Geospatial Image Processing library.   The underlying dataset resides on disk and is interfaced through GDAL, and is read and processed in chunks, and written out.   My goal is to make the file I/O and chunking process as transparent as possible to the developer.  I'm essentially applying the power and ease of use of the CImg library to Geospatial imagery.   My hope is to make is publicly available but as both libraries are LGPL it is ultimately up to my boss to make that decision.
>  

How does what you try to accomplish differ from what can be done with OSSIM?

My first  impression, after looking briefly at CImg's website, is that
marrying GDAL and CImg elegantly won't be easy. It may be easy to use
GDAL to bring a piece of one band into CImg but not so easy to support
processing big images with CImg. I would assume taking chunks,
processing them, and putting them together again does not produce
correct results in all cases.

Ari

--
Prof. Ari Jolma
Kartografia ja Geoinformatiikka / Cartography and Geoinformatics
Teknillinen Korkeakoulu / Helsinki University of Technology
POBox 1200, 02015 TKK, Finland
Email: ari.jolma at tkk.fi URL: http://www.tkk.fi/~jolma