Thank you all for answering my question.I will look for another way to handle
NTv2.
Sun
________________________________
From: Andrea Aime <aa...@opengeo.org>
To: Rueben Schulz <r_j_sch...@yahoo.ca>
Cc: Li Sun <lisu...@yahoo.ca>; geotools-gt2-users@lists.sourceforge.net
Sent: Tue, November 24, 2009 1:42:59 AM
Subject: Re: [Geotools-gt2-users] NTV1 and NTV2 support
Rueben Schulz ha scritto:
> To Sun,
>
> The short answer is no, geotools does not support NTV2 (or 1). If it
> did, the math transform would be in the referencing module, beside the
> NADCON transform (a similar NAD27 to NAD83 datum shift method used in
> the USA).
>
> http://geotools.org/javadocs/org/geotools/referencing/operation/transform/NADCONTransform.html
>
> I looked into adding NTV2 many years ago (there may even be an email on
> the devel list about it somewhere), but while the people at Natural
> Resources Canada were very helpful, they were not at that time setup to
> license to an open source project. I think there is a fee to license the
> NTV2 files (which you are then allowed to distribute), and various
> agreements need to be signed to guarantee to them that your
> implementation is correct. Now that Geotools is under the OSGeo
> Foundation, getting this licensing sorted out should be much easier.
I actually successfully made a NTV2 transform some time ago, when
checking how hard it would have been to integrate, by using the
http://jgridshift.sourceforge.net/ library and a grid that was
kindly provided to me by a national cartographic representative
(a grid that I cannot share, as you say it's something that is being
sold).
Long story short, it's definitely doable, it would just take some
time to make to integrate in GeoTools and to make
grid lookups flexible enough to be usable in a variety of situations:
think custom apps putting them in the classpath, GeoServer probably
putting them somewhere in the data directory, uDig somewhere else,
and so on.
We'd probably also need some way to declare that a grid is available
besides the cases already contemplated by the EPSG database itself
(and override factory, but for datum transformations as opposed
to CRS definitions).
Sounds like one-two weeks of work, but it's definitely doable.
Cheers
Andrea
-- Andrea Aime
OpenGeo - http://opengeo.org
Expert service straight from the developers.
__________________________________________________________________
Looking for the perfect gift? Give the gift of Flickr!
http://www.flickr.com/gift/------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
trial. Simplify your report design, integration and deployment - and focus on
what you do best, core application coding. Discover what's new with
Crystal Reports now. http://p.sf.net/sfu/bobj-july
_______________________________________________
Geotools-gt2-users mailing list
Geotools-gt2-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
