[Gvsig_english] New Student for GVSIG within Google Summer OfCode2010: quick introduction

Mon May 17 13:51:56 CEST 2010

Hi Ben,

Benjamin Ducke escribió:
> Hi Juan Lucas
>
>   
>> As for Luca's project, I think JNI (on top of OGR or
>> SQLite/Spatialite) is unavoidable, no? OpenJUMP's plugin might be a
>> reference, as somebody said. They are using a JAR that includes a
>> native library (.dll, .so) in it:
>>
>> https://sourceforge.net/apps/mediawiki/jump-pilot/index.php?title=OpenJUMP_with_SpatialLite
>>
>>     
>
> Thanks for the link. There will certainly be interesting information
> in there.
>
> If we go for the simple WKB/WKT storage model, then Luca could model
> his work on the existing code for the PostGIS driver and avoid having
> to use JNI, at least until support for the native SpatiaLite format
> is required (but then that can still be done via the existing 
> GDAL/OGR driver bindings).
>   

I agree the simple model may be interesting, as a way to be able to work 
with existing sqlite databases or even as a first phase of development.

That work should be quite quick and easy, as there is a base 
implementation for JDBC based DAL providers, and our current Postgis and 
Mysql providers are already reading and writing geometries in WKB format 
by themselves, so they are good examples to start from.

But I think we shall go to the full spatialite support. gvSIG needs 
support for a local personal database, for many uses (cache, temporal 
storage, etc.), and we still haven't one because the java based ones 
(HSQLDB, etc.) doesn't have proper spatial support. With spatial support 
I mean, above all, spatial indexes support, or I fear performance will 
suffer badly.

I don't know if that work is too much to be done in the period available 
for Luca in the GsC, and should be continued in the next year's GsC, or 
by some other volunteer/s, but I would like to stress the importance of 
having spatialite support, at least at spatial indexes level.

Regards,

-- 
Cèsar Ordiñana Navarro
gvSIG software architect
DiSiD Technologies (http://www.disid.com)

> Cheers,
>
> Ben
>
>   
>> Nacho's work sounds very interesting too.
>>
>> Regards,
>>
>>
>> Juan Lucas Domínguez Rubio
>> ---
>> Prodevelop SL, Valencia (España)
>>
>> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
>> http://www.prodevelop.es
>> ---
>>
>>
>> De: gvsig_internacional-bounces at listserv.gva.es en nombre de Benjamin
>> Ducke
>> Enviado el: lun 17/05/2010 9:28
>> Para: Users and Developers mailing list
>> Asunto: Re: [Gvsig_english] New Student for GVSIG within Google Summer
>> OfCode2010: quick introduction
>>
>>
>>
>>
>>     
>>> Ben,
>>>
>>> you know for sure much better than me what would mean having
>>>       
>> problems
>>     
>>> with wrapping of C API so if we will have too much pain with
>>> SpatiaLite it could be perfect use the plain WKT/WKB. I've given a
>>> glance to the link you've suggested but I should read it better for
>>> understanding what it means on the development point of view.
>>>
>>> Ciao,
>>> Luca
>>>
>>>       
>> I think for a first stage implementation, the simple WKB/WKT
>> storage model is probably best. Others can always be added later
>> using the new GDAL 1.7 java bindings. That way, you shouldn't
>> have to worry about maintaining your own JNI stuff (which can
>> be a real pain).
>>
>> Give users the choice to use WKB (more compact) or WKT (more
>> easy to parse) when storing geometries. When reading, the
>> format should be auto-detected.
>>
>> Let me know if you have any problems understanding anything.
>> I can send you a little sample SQLite3 database with some WKB/WKT
>> tables for illustration. I produced them in GRASS GIS using the
>> GDAL/OGR drivers.
>>
>> But maybe start by adding plain SQLite3 non-spatial tables as
>> a new project document type first. And then work towards spatial
>> tables from there -- to keep things a little more simple for you
>> at the start!
>>
>> Best,
>>
>> Ben
>>
>>     
>>> [1] http://www.iosa.it/blogs/luca
>>> 2010/5/14 Benjamin Ducke <benjamin.ducke at oxfordarch.co.uk>
>>> Hi Juan, Luca
>>>
>>> That question is not so rhetorical, actually!
>>> There are several ways of storing spatial data in an SQLite3
>>> database, that are all in use by some software:
>>>
>>> http://www.gdal.org/ogr/drv_sqlite.html
>>>
>>> One of them is a simple WKT/WKB storage model that is also nicely
>>> documented (see link above).
>>>
>>> So if SpatiaLite is too much pain, because of the need to wrap the
>>> C API, then we can just use the plain WKT/WKB storage for our
>>> purposes.
>>> It's supported by GDAL/OGR, so we lose only the special SpatiaLite
>>> functionality.
>>>
>>> Cheers,
>>>
>>> Ben
>>>
>>> ----- Original Message -----
>>> From: "Juan Lucas Dominguez Rubio" <jldominguez at prodevelop.es>
>>> To: "Users and Developers mailing list"
>>> <gvsig_internacional at listserv.gva.es>, "Gvsig internacional"
>>> <Gvsig_internacional at listserv.gva.es>
>>> Sent: Friday, May 14, 2010 2:38:44 PM GMT +01:00 Amsterdam / Berlin
>>>       
>> /
>>     
>>> Bern / Rome / Stockholm / Vienna
>>> Subject: Re: [Gvsig_english] New Student for GVSIG within Google
>>> Summer Of Code2010: quick introduction
>>>
>>>
>>>
>>>
>>> Ciao, Luca.
>>>
>>> I too think Spatialite is a very interesting way to store and share
>>> GIS data, especially because its simplicity fits mobile devices very
>>> well.
>>>
>>> I know a pure-Java version of SQLite (not Spatialite) which will
>>> probably work on a wide range of Java-enabled mobile devices
>>>       
>> (Android
>>     
>>> supports SQlite too).
>>>
>>> I was wondering: what is the simplest Sqlite database that can be
>>>       
>> read
>>     
>>> and processed from Spatialite? Let's suppose I have a Sqlite
>>>       
>> database
>>     
>>> file with only one table and one of the columns of that table is of
>>> binary type (BLOB or similar), and that column contains some WKB
>>> describing a geometry. Would this be enough to open it from a
>>> Spatialite-enabled application (for example gvSIG in the future)?
>>>       
>> This
>>     
>>> is rather a rhetorical question... I need to look into it myself :)
>>>
>>> Can we see your progresses online? blog? SVN?
>>>
>>> Regards,
>>>
>>>
>>> Juan Lucas Domínguez Rubio
>>> ---
>>> Prodevelop SL, Valencia (España)
>>>
>>> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
>>> http://www.prodevelop.es
>>> ---
>>>
>>>
>>> De: gvsig_internacional-bounces at listserv.gva.es en nombre de luca
>>> bianconi
>>> Enviado el: jue 06/05/2010 15:17
>>> Para: Gvsig_internacional at listserv.gva.es
>>> Asunto: [Gvsig_english] New Student for GVSIG within Google Summer
>>>       
>> Of
>>     
>>> Code2010: quick introduction
>>>
>>>
>>> Hello gvsig-international mailing list,
>>>
>>> sorry for sending this email as a kind of spamming, I'd like just to
>>> introduce myself quickly to the whole list.
>>>
>>> My name is Luca Bianconi and I'm the "student" working with the
>>>       
>> gvSig
>>     
>>> team for the Google Summer of Code 2010.
>>> Our task is implementing the gvSig support for SQlite and SpatiaLite
>>> and I'll do my best for doing it.
>>>
>>> I'd like to say my "Hello" to everybody and I thank you all for the
>>> help you will be able to provide when we will be up to the
>>> implementation phase both in comments and suggestions!
>>>
>>> Nice to meet you all,
>>> Cheers,
>>> Luca
>>> _______________________________________________
>>>       

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