[Live-demo] GGL2 application for OSGeo Live

[Víctor González]

Hello again,

Seems like we have to work a little more in order to get our software
included in the next OsGeo Live DVD release. It is released every year,
right? However, I'll reply your questions inline.

Regards,
Víctor.

El 3 de enero de 2012 21:00, Cameron Shorter
<cameron.shorter at gmail.com>escribió:

>  Hello Víctor,
>
> Great to hear about your interest in OSGeo-Live. GGL2 does sound like it
> is a good candidate, although there are a few hurdles I see before it would
> be a suitable candidate. In particular, I don't see there being enough time
> to make our 5.5 release which has a feature freeze on 7 January 2012. I
> have some comments inline, but firstly a few general questions.
>
>
>
> On 02/01/12 22:34, Víctor González wrote:
>
> Hi,
>
> I'm Víctor González and I'm currently working for the GGL2 project [1]. We
> would like to include it into the OSGeo Live DVD, so I have answered all
> the questions in the wiki [2] further down. Let me know if there is
> anything else that we need to do in order to include it.
>
> Thanks in advance,
> Víctor.
>
> [1] http://www.gearscape.org
> [2] http://wiki.osgeo.org/wiki/Live_GIS_Disc_Apply
>
> ---------------------
> * * What is its name? *
> GGL2
>  ** What is the home page URL?*
> http://www.gearscape.org
>  ** Which OSI approved Open Source License is used? *
> GPLv3
>  ** What does the application do and how does it add value to the
> GeoSpatial stack of software? *
> The application provides a new geoprocessing language with specific
> constructions to make geoprocessing creation more easy and reliable. It can
> be connected to GIS applications such as gvSIG in order to get the data and
> show the results so it interacts with some of the GeoSpatial stack of
> software in order to add new geoprocessing capabilities (fast creation and
> execution of custom geo-algorithms).
>
>
> This sounds like it has similar capability to that offered by the Web
> Processing Service (WPS) standard.
> Do GGL2 make use of the standard? If so, how?
> If not, why not?
> I see that this question is not in the wiki page you copied from, so I've
> just added the following line:
> "Does the application make use of OGC standards? Which versions of the
> standards? Client or server? You may wish to add comments about how
> standards are used."
>

GGL2 is the second version of the Gearscape Geoprocessing Language (GGL).
The first version was integrated into the 52º North WPS a few years ago (
http://52north.org/about/other-activities/2009-student-innovation-prize).
So we think that, firstly, a GGL2 process can be included into a WPS just
like we did before, and we plan to integrate the new version of the
language again into WPS. Plus, since it is possible to extend GGL2 to add
new "readers" (they can be seen as data providers), it could be possible to
include the result of a WPS execution as a variable in the GGL2 code.
However, this is not implemented and our priority is the integration on the
server side.

On the other hand, the geometry model we use in GGL2 is the same as in JTS,
so we use the Simple Feature Access for SQL standard.


>
> Also, I'm interested to understand the relationship with ETL tools like
> GeoKettle, or Business Process Execution Languages and tools like
> Bonitasoft, http://www.bonitasoft.com/ . Does GGL2 provide the same type
> of functionality as provided by GeoKettle or Bonitasoft?
>
>
Typically GGL2 scripts will Extract-Transform-Load data, but it is a
programming language so I guess it provides more flexibility (not sure
since I'm not user of GeoKettle nor any ETL tool).

GGL2 is a programming language aimed at writing geoprocesses easily.
I've read Geokettle provides scripting capabilities to transform data
based on javascript, SQL and regexp. GGL2 provides much more than that
so I dare say it is more fine grained. For example, with GGL2 it is
possible to set the Z coordinate of a vector dataset to the value of a
DEM with very few statements. It is possible also to consume web
services, etc.

As I said before, our plan is to stabilize the language and then integrate
it wherever
we can: WPS servers again and maybe, why not, Geokettle.

Regarding Business Process Execution Languages. GGL2 is focused on
data: it provides a data abstraction (it has "geometry" and "raster"
datatypes) and constructions to process it. I guess it's not the same
thing.


>
> ** Which language is it written in? *
>  Java
>  * * Which version of the application should be included in the next
> OSGeo-Live release? *
> GGL2 m3 (milestone 3)
>  ** What is the size of the user community?*
> We had almost 500 downloads over the last two months. However, the mailing
> lists has been recreated a few months ago and they are not really busy yet:
> http://ggl2-usuarios.1062791.n5.nabble.com
>  http://ggl2-users.1062796.n5.nabble.com
>  ** What is the size of your developer community? *
>  We are two active developers.
>  ** Do you have a bug free, stable release? *
> Not yet. Bug fixing (http://xp-dev.com/trac/ggl2/report/1) is the next
> step in our roadmap and we plan to do so in the next few months, but the
> latest release (milestone 3) is not intended for production scenarios.
>
>
> For OSGeo-Live, we are only looking for rock-solid stable applications. We
> are wanting to demonstrate to new users that there is quality, production
> ready Open Source Software, and if a user strikes a bug or error then this
> will reflect badly on all other applications installed on OSGeo-Live.
>
> It sounds like GGL2 is not ready yet, but will likely be ready in future
> releases.
>
>
>

>  ** Please, discuss the level of testing that your project has gone
> through. How long has the project has had mature code. *
> The application is based on the Eclipse platform, similiar to the uDig
> approach, so we can trust on the platform stability. Apart of that, the
> GGL2 code running on top of that platform reuses some code from the
> previous GGL version, which was stable. Moreover, we have over 300 tests
> checking the code correction and stability.
>
>
> Are the 300 tests periodically run? Maybe during the build process? Or
> using hudson or similar?
>
>
We don't use any continuous integration system but tests are run very
frequently. We're only two developers and both of us are aware of the
importance of stability.


>  ** Does the application have a user interface that a user can interact
> with? *
> Yes, the user interface is inherited from the Eclipse platform.
>  ** Who will act as the project's liaison person? *
>  I will play that role.
>  ** Can you please discuss how your application will be installed.*
> Just like Eclipse, simply unzip the package. If gvSIG is installed, unzip
> the plugin into the gvSIG extensions directory and we're ready to go.
>  ** Can the application run in 512M of RAM? *
> The minimum required memory to run the application is 128M, so yes, it
> can. However, it will require more memory for geoprocessing. Whether 512M
> is enough or not will depend on the geoprocess algorithm and data.
>  ** How much disk space will be required to install the application and a
> suitable example application? *
> Less than 200M.
>
>
> This is quite large and we are getting very short of disk space. Are you
> including java in this 200M? (You don't need to). gvsig is already
> installed. Can you reduce disk space by bundling with gvsig?
>
>
Java is not included in the 200M amount, but since we use the same plugin
system than Eclipse, we can remove some optional plugins or features in
order to reduce disk space. Moreover, we plan to release a command-line
version that will be more lightweight. We will have this issue in mind for
our next releases.


>
>  ** If another dataset would be more approriate, please discuss here*.
> Maybe it will be interesting to have some CSV or GPX files to work with.
> We can include some simple sample files in our own package/sample project
> and it will not exceed the 200M limit.
>
>
> Our strong preference is to make use of existing datasets in order to
> reduce disk space, and maintenance of the data. Are you able to make use of
> existing datasets?
>
>
Yes I am. No problem.

> ** Each OSGeo-Live application requires a Project Overview available
> under a CC By and a Quickstart available under a CC By-SA license. Will you
> produce this? *
>  Yes.
>  ** In past releases, we have included Windows and Mac installers for
> some applications. It is likely we won't have space for these in future
> releases. However, if there is room, would you be wishing to include
> Windows and Mac installers?*
> It is not necessary.
>
>
> _______________________________________________
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>
>
>
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