On Tue, Dec 31, 2013 at 1:18 PM, Jonathan Moules <
[email protected]> wrote:
>
>> Then again, Jonathan has this data in Oracle... I did not want to venture
>> there: loading
>> data there is a pain, the styles need fixing because of the uppercase
>> attributes,
>> and honestly, why waste an open source developer spare time on closed
>> source databases anyways?
>
> Completely concur. And thanks for all your work given it's your free time!
> (That said, these styles are completely interchangeable between shapefile
> and our Oracle, with just one change - search/replace "ROAD_NO" (shapefile)
> to "ROAD_NUMBER" (Oracle)).
>
> Now, this is PostGIS specific (no
>> plain simplification in Oracle, only the topology preserving one is
>> available, which
>> is supposedly more expensive than not doing it, at least, it is in
>> PostGIS),
>
>
> There is plain "simplify" in Oracle:
> http://docs.oracle.com/cd/E11882_01/appdev.112/e11830/sdo_util.htm#BJEHCIBF-
> that tool is available via Oracle Locator and doesn't require Oracle
> Spatial. It's just a simple Douglas-Peucker implementation
> *"Topological characteristics of the input geometry might not be
> maintained after simplification."*
>
Ah, doh, I looked at that page and for some reason I thought it was
topology preserving.
Btw, how did you import your data in Oracle again? ogr2ogr?
>
> Spatialite of course has one too -
> http://www.gaia-gis.it/gaia-sins/spatialite-sql-4.1.0.html#p6
>
> And with MSSQL Server it seems to be "Reduce" -
> http://technet.microsoft.com/en-us/library/bb933814.aspx
>
Cool stuff
>
> I don't know if OGR is used as an input source in GeoServer (shapefile
> reading?), but it appears to have a Simplify function too (If I'm looking
> in the right place) -
> http://www.gdal.org/ogr/classOGRGeometry.html#afd3ea0ffa1e2994427032d0212206ccf
>
Shapefile reading is done via pure java code. We do have an unsupported OGR
based store in GeoTools (which I've originally developed, guess what, in my
spare time), but it has been difficult to make it graduate
to supported status as installations that could justify the work normally
try to stay away from native packages, unless they are super-duper tested
(as they will bring down the whole JVM if they segfault). Sort of catch 22
situation...
>
> So the ST_Simplify optimisation could potentially be carried over to other
> datastores (although that does presume that ST_Simplify is as fast on the
> other implementations as it is in PostGIS).
>
Right, that needs to be verified indeed.
>
> Again, thanks for your free-time work! :-)
>
Always happy to spend some time looking into performance improvements :-p
Cheers
Andrea
--
*== GeoSolutions will be closed for seasonal holidays from 23/12/2013 to
06/01/2014 ==*
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
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