Re: [Jaspa-users] Questions

[Jose C. M. L. <jom...@cg...>]

Hi Simon,

On 11/01/2012 2:56, Simon Greener wrote:
> Jose,
>
>       Hi Simon, I know you because of the mailing list and your great
>     blog.
>
>
> Most kind. I know this is hard to believe but I get little recognition 
> for what I do so it is nice to hear it.
> I am actually quite ready to move to another database like PostGIS but 
> there is so little work in that space
> in Australia. SQL Server Spatial is my other option mainly because of 
> the amount of installs in Oz. Working
> with Oracle is awful.
>
>>     Jaspa Users,
>>
>>     I have a question. I am looking at either porting JASPA to Oracle
>>     to work in conjunction with SDO_GEOMETRY
>>     or to pull out particular methods for use on their own augmenting
>>     Oracle Sdo_Geometry functionality.
>     Marta Gonzales who has worked with me in the jaspa project is
>     working now about porting Jaspa to Oracle 11g in her Master
>     thesis. She has already done a good job about that using the
>     spatial indexes and migrating most of the jaspa functionality. I
>     dont know exactly the current status of her work but the idea is
>     to add it to the jaspa release.
>
>       Marta is you read this email maybe you can give some details
>     about your work to Simon.
>
>
> OK, look I have been working on exposing JTS in Oracle's JVM now for 
> quite a while. I am doing it more directly looking a functionality
> that complements or fills gaps in the Oracle stack rather than any 
> theoretically complete OGC/SFS compliant API. The results of my work
> are documented on my website under what is called the GEOPROCESS 
> PL/SQL package. I have actually renamed this to JTS and added
> in a lot more functionality. It is ready to go up on my site to 
> replace GEOPROCESS but it may not happen till next week. Still, GEOPROCESS
> gives you a feel for what I have done.
Thats good to know Simon, I think Marta already learned things from your 
blog about oracle. Im gonna meet her maybe tomorrow or Friday to see her 
work. She already told me though that at the beginning she started with 
Oracle 10.2 and java 1.4 but she changed to oracle 11 because she had 
problems with Jaspa, probably because java 1.5
The Jaspa idea about Oracle was to avoid some people to pay oracle 
spatial license and use Jaspa instead of it.
>
>
>>     *Firstly*, I note that Jaspa appears to have its own version of
>>     JTS as its definition of Coordinate.java includes a measure.
>>     I am currently working with JTS1.12 and its Coordinate.java does
>>     not have a measure ordinate. Is this the case? How deep
>>     do the changes go? Is there a plan to fold them back into JTS?
>       yes, you are right, jaspa has modified JTS but just a little bit
>     like the one you found out or a few methods. I dont think the
>     changes are useful for every jts users thats why I didnt even ask
>     Martin Davis about that.
>
>
> It is very important that you do merge this back into JTS. One major 
> issue I have with GeoTools/JTS is the handling of 3 and 4D geometies, 
> never mind the bigger issues of circular curve and geodetic support.
>
> As part of my GeoRaptor work exporting Oracle data to shapefiles, I 
> looked at the conversion from GeoTools to JTS and back again for 
> Oracle because it does not handle measures.
> To be honest, even though I am not a vastly experienced profesional 
> and full-time Java programmer I wasn't impressed with the code. It 
> didn't just need a fix for the measures it needed a complete
> re-write. I started work on the "fix" with Jody Garnett but I lost 
> interest for a bunch of reasons.
>
> Perhaps JASPA is the better framework in which to get Oracle/JTS 
> integration working.
>
> What are your plans for circular arc and geodetic support given that 
> JTS doesn't support either?
>
Geodetic support is very attractive research for me, specially because 
my mayor is Engineering in Geodesy and Cartography but before trying to 
implement Geodetic support in a serious way Jaspa must implement a 
tolerance system, as cluster in ArcGIS. Unfortunately PostGIS does not 
implement a tolerance system either  and its incredible!!

I think Martin Davis is working in geodetic support in JTS but JTS does 
not support tolerance system either.

> (Aside: How is it that PostGIS etc all seem to use JTS/GEOS but from 
> that basis extend to support circular arcs etc but don't work to help 
> JTS/GEOS get that support?)
The support of  PostGIS with curve geometries is very limited. In fact, 
if you wanna use the main spatial functionality you have to convert from 
and to curve geometries. It does not make sense for me.
In  my opinion PostGIS project should have funded a lot the JTS project 
because the JTS project is the PostGIS Core.
>
>     *Secondly*, I prefer to work with Java 1.4 as Oracle 10gR2 is 1.4
>     and only 11g is 1.5.  All in all this doesn't look too difficult
>     an issue
>>     if I pull out functions but more so if I work with Jaspa as a whole.
>>
>>     *Thirdly*, JASPA seems to allow for auto conversion of primitive
>>     ints to Integers, boolean to Boolean in its functions .... when
>>     moving
>>     back to an earlier JVM it is a pain because one has to do formal
>>     conversions eg
>>
>>     public static Double ST_Area(Geometry geom) {
>>
>>     if (Core.isNullGeometry(geom)) return null;
>>
>>     return geom.getArea();
>>     }
>>
>>     public static Double ST_Area(Geometry geom) {
>>
>>     if (Core.isNullGeometry(geom)) return null;
>>
>>       return new Double(geom.getArea()) ;
>>     }
>>
>>     I can see why one might use class types over the primitive types
>>     but wouldn't more formal casting/conversion from JTS to JASPA be
>>     better than compiler based conversion? But I have to admit I am
>>     not a vastly experienced Java programmer. When going from Oracle's
>>     PL/SQL to the JVM I use primitive types.
>     I think you are right about formal casting/conversion, it was just
>     for writing less code. You are talking just about the returning
>     values or you found any other problem with java 1.4 and Oracle?
>     Anyways this project is mainly maintained by me and I dont think i
>     can change the source code a lot right now because lack of time.
>     For the next release I can change the casting as you suggested if
>     you think this is really worth it.
>
>
> It is not a difficult thing to do. Mainly it is because of JASPA's use 
> of class data types like Integer whereas JTS uses the primitive types 
> like int. So, yes, I suggest you make the change.
>
> The only other changes I needed to make (for 1.4 compliance as JTS is 
> 1.4 compliant) were to change things like List<Geometry> ... to List 
> and add in casts when needed. This was actually very simple to do as JASPA
> doesn't seem to use LinkedHashMaps etc with key/value typing. The only 
> pain is:
>
>     public static <U> U[] removeNulls(U array[]) {
>
I would prefer to keep going with Oracle 11 and not change the Jaspa 
code about using java 1.4. I remember that I changed many methods with 
parametric types as List. e. g.: List <Geometry> list = ...
> I would be happy to change the code for you in agreed areas but only 
> once the Oracle integration has occurred. Also, I am happy to offer to 
> test Marta's work if you are interested.
> Perhaps once Marta is finished I could be involved as the maintainer 
> of this branch of the code? But isn't one thing about JASPA to offer 
> an alternate type system to Oracle (BTW
> aggregates with Java in Oracle are awful!) My needs are for a solution 
> that is about integration.
>
> Happy to keep talking or get involved in any way you are comfortable with.
We are happy too you can get involved in the Jaspa project. When Marta 
finishes her work (I think soon), we will send it to you and we will 
keep talking about that.
Marta is going to start working in a company  so probably no one is 
going to maintain the Oracle branch code, so you are very welcome.

I will talk to Marta about testing her project too.

Regards,

>
> regards
> Simon
> -- 
> Holder of "2011 Oracle Spatial Excellence Award for Education and 
> Research."
> SpatialDB Advice and Design, Solutions Architecture and Programming,
> Oracle Database 10g Administrator Certified Associate; Oracle Database 
> 10g SQL Certified Professional
> Oracle Spatial, SQL Server, PostGIS, MySQL, ArcSDE, Manifold GIS, FME, 
> Radius Topology and Studio Specialist.
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