Re: [Jts-topo-suite-user] What to do with Spatial4j?

[Jody G. <jod...@gm...>]

A couple quick thoughts, I had not heard of the project before but I really
like the idea of having an answer to PostGIS geography type for the Java
community.

And it is good that Martin's recent email on moving JTS to BSD+EPL is
having an immediate benefit, I wonder how many other projects are held back
by a non LGPL requirement.

I have been going through the steps of joining LocationTech for the uDig
project. When that group was being formed I tried to provide clear marching
orders: ie implementation of Geometry and Referencing. That list appears to
be expanding to include geocoding (providing a bridge from business objects
to location). If you are interested I suggest getting in early while a
technology stack is being assembled - it would be a valuable contribution.

As for it being used - it may not be clear, but the GeoTools feature model
does support using different implementations for the "geometry" of a
feature and I have long looked for an excuse to try this out. This mostly
needless flexibility was originally intended to allow the library a chance
to work with any ISO 19107 implementations that came along. I suspect that
following in the footsteps of PostGIS with a Geography representation makes
more immediate sense.



On Wed, Sep 25, 2013 at 4:06 PM, Smiley, David W. <ds...@mi...> wrote:

>  Hello JTS list,
>
>  I'm writing to solicit the opinions of the folks on the JTS list on the
> direction I should take with Spatial4j — a ~2 year old open-source project
> I run with Ryan McKinley.
> https://github.com/spatial4j/spatial4j
>
>  Background:
> Spatial4j came about as a subset of a body of Java spatial code in support
> of spatial information-retrieval for Apache Lucene and Solr. Spatial4j is
> the subset that deals solely with defining shapes, computing distances,
> shape intersection, and parsing and writing shape strings. To my knowledge,
> it is only used by Lucene's new spatial module. Spatial4j is an independent
> part of Lucene spatial for two reasons: Most importantly, it uses (albeit
> optionally) the 3rd party JTS library which is LGPL licensed. The Apache
> Software Foundations forbids a dependency, even an optional one, on LGPL
> licensed software. The second reason is that Spatial4j should be
> independently useful on its own. I don't know of the geodetic shape
> intersection algorithms it has existing in any other open-source software.
> Perhaps I didn't look hard enough but that is to the best of my knowledge.
>
>  Some specific features of note to the list here:
>  * A circle implementation, both in euclidean 2D mode and geodetic
> surface-of-sphere mode
>  * computs intersection cases (disjoint, contains, within, intersects)
> between the shapes it has and points and rectangles (either euclidean 2D or
> geodetic)
>  * Rewrites JTS geometries of lat & lon coordinates to support dateline
> crossing.  No pole wrap support yet.
> There are extensive randomized tests, by the way.
>
>  So there's useful code here for sure, but it's only used by Lucene's
> Spatial module (which I work on a great deal).  With JTS about to be
> re-licesned in a way compatible with ASF projects, it is no longer required
> that Spatial4j's code exist outside of Lucene spatial.
>
>  I'm thinking of taking one of two paths:
>  (A) Merge it into Apache Lucene's spatial module.  I'm a committer there.
>  Spatial4j as an independent project would be effectively dead but the code
> would live on co-located where it is used.  It would always be in sync with
> Lucene (no separate releases).
>  (B) Join LocationTech.  This approach will only be deemed successful, as
> far as I'm concerned, if "eventually" people start using it.
>
>  What do you guys think of Spatial4j and what I should do with it?
>
>  ~ David Smiley
>
>
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