[Gdal-dev] Re: [UMN_MAPSERVER-DEV] MapServer and ECW

[Bill Binko]

On Tue, 28 Jun 2005, Frank Warmerdam wrote:

> On 6/28/05, Daniel Morissette <dmorissette at dmsolutions.ca> wrote:
> > This question is probably more for Frank, but I am interested in
> > feedback from anyone else who has played with MapServer and ECW on Linux
> > already...
> > 

I have seemed to taken on this yoke recently :)  (I got 16GB of compressed 
ECW DOQQs for $40, and suddenly, I cared about making it work.)

> > Now that ER-Mapper has modified its license to allow use of the ECW SDK
> > with open source server software such as MapServer, we need to get
> > Mapserver working with ECW on one of our client's servers. However,
> > before we go through the same experience as for MrSid, I'd like to know
> > if anyone else has tested/used MapServer with ECW files on Linux? Are
> > there specific requirements (GDAL version, DSDK version, etc.)? Anything
> > else we should know about?

If you have the option, I would wait until the next release of the SDK 
from ERMapper -- even the next Beta.  Tom Lynch (who has been a very good 
resource) says that the next version should have my fixes and may (MAY) 
have a autoconf-based (or at least better) build.

If you want to get started right away, I have had luck with GDAL 1.2.6 and 
the 3.1 release of the SDK -- if you apply my patch.  My patch is fairly 
simple: there is an uninitialized boolean member on one of their classes.  
If it's built with -g, it gets zeroed and works, if it's compiled with -O, 
it doesn't and it's random as to whether or not the program (or mapscript 
call) will ever return.

Here's a forum at ERMapper that is worth following (it also has my patch):

http://forums.ermapper.com/viewtopic.php?t=486&highlight=

Frank has made 3.2beta work with GDAL CVS Head (as he mentioned).  Here's 
a note on ermapper.com that helps there;

http://forums.ermapper.com/viewtopic.php?t=680&highlight=

>From what Frank says, I should be able to use gdal_merge.py with the CVS 
HEAD which has had some issues with 3.1.  However, I've been working on 
some PostGIS performance issues with strk and have put it off.  That needs 
to change.

Along the way, I ended up writting a small utility that lets you edit the 
headers of ECW files (adding Projections, etc.).  I have released that GPL 
and have given Tom the rights to ship it under their choice of license as 
well, so hopefully that will be a positive outcome of some of the pain.

I hope this helps.

Bill

PS: Tom, that beta3 would be great :)