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From "Mattmann, Chris A (388J)" <chris.a.mattm...@jpl.nasa.gov>
Subject Re: Rethinking spatial implementation
Date Mon, 08 Nov 2010 14:06:39 GMT
Hi All,

FYI, Apache SIS [1], currently Incubating, is working on building an ASLv2 licensed library
comparable to JTS or GeoTools. You'll notice that most of the GIS related libs out there are
GPL or LGPL (or at least I did), so I decided to do something about it.

If anyone else is interested in joining the cause, we'd welcome you over there.

At present, we have code that implements a QuadTree storage and does PointRadius and bounding
box computations, as well as a REST-ful web service to handle spatial location based on those
2 methods. We're close to making an 0.1-incubating release.

Cheers,
Chris

[1] http://incubator.apache.org/sis/


On 11/8/10 2:40 AM, "Chris Male" <gento0nz@gmail.com> wrote:

Hi,

I'll jump in and give my opinion:

Can you clarify what you mean with "the Sinusoidal projection is broken"?

Inside Spatial Lucene's Cartesian codebase is an implementation of Sinusoidal projection.
 Grant discovered while working on improving the testing coverage of the code that the implementation
doesn't actually match the formula specified on Wikipedia.  When we tried to change it, many
tests broke since the overall logic somehow depends on this broken implementation.


Would it be possible to use a LGPL library like the Java Topology Suite (JTS: http://www.vividsolutions.com/jts/JTSHome.htm)?

This is something we've talked about using.  I think it would be nice to offload some of the
geographic-specific from Lucene.  So using another library would be good.  At the same time
it limits our options for optimizations and the like.  I'm certainly looking into it though.

Thanks,
Chris


Neo4j is using JTS for creating a spatial index (code is here: https://github.com/neo4j/neo4j-spatial)...

(I've just seen that JTS has some index creation classes, but I'm not at all familiar with
them)

Christopher


On Mon, Nov 8, 2010 at 1:10 AM, Grant Ingersoll <gsingers@apache.org> wrote:

On Nov 6, 2010, at 5:23 PM, Christopher Schmidt wrote:

> Hi Ryan, thx for your answer.
>
> You mean there is room for improvement and volunteers?

We've been looking at replacing it with the Military Grid system.  The primary issue with
the current is that the Sinusoidal projection is broken which then breaks almost all the tests.
 I worked on it for a while trying to straighten it out, but gave up and now think it is easier
to implement clean.  I definitely would like to see a tier/grid implementation.


>
> On Friday, November 5, 2010, Ryan McKinley <ryantxu@gmail.com> wrote:
>> Hi Christopher -
>>
>> I do not believe there is any active work on this.  From what I
>> understand, the Tier implementation works OK within some constraints,
>> but we could not get it to pass more robust testing that the other
>> methods were using.
>>
>> However, LatLonType and GeoHashField are well tested and work well --
>> the Tier type may have better performance when your index is really
>> large, but no active developers understand it and no-one has stepped
>> up to figure it out.
>>
>> ryan
>>
>>
>> On Wed, Nov 3, 2010 at 3:16 PM, Christopher Schmidt
>> <fakod666@googlemail.com> wrote:
>>> Hi all,
>>> I saw a mail thread "Rethinking Cartesian Tiers implementation" (here).
>>> Is there any work in progress regarding this? If yes, is the current
>>> implementation deprecated or do you plan some enhancements (other
>>> projections or spatial indexes) ?
>>> I am asking because I want to use Lucene's spatial indexing in a production
>>> system...
>>>
>>> --
>>> Christopher
>>> twitter: @fakod
>>> blog: http://blog.fakod.eu
>>>
>>
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>>
>
> --
> Christopher
> twitter: @fakod
> blog: http://blog.fakod.eu
>
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--------------------------
Grant Ingersoll
http://www.lucidimagination.com/

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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Chris Mattmann, Ph.D.
Senior Computer Scientist
NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
Office: 171-266B, Mailstop: 171-246
Email: Chris.Mattmann@jpl.nasa.gov
WWW:   http://sunset.usc.edu/~mattmann/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Adjunct Assistant Professor, Computer Science Department
University of Southern California, Los Angeles, CA 90089 USA
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


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