Hi Mauro, When you say AggregationFunctions enum you mean this one: https://github.com/nmco/geotools/blob/917d43efca4a920ec3153304d644883101ca3921/modules/library/main/src/main/java/org/geotools/feature/visitor/Aggregate.java
One thing is not clear to me, will this computation by delegate the underling data store when possible ? For example this aggregation can be done like this in Postgis (using some OSM data as an example): SELECT admin_level, SUM(ST_AREA(geometry)) FROM public_osm_administrative_version_log GROUP BY admin_level; Since the aggregate attribute is an /Expression/: https://github.com/nmco/geotools/blob/917d43efca4a920ec3153304d644883101ca3921/modules/library/main/src/main/java/org/geotools/feature/visitor/GroupByVisitorBuilder.java#L37 I guess the attribute can be encoded as a function call and the SUM aggregation used to compute the aggregation. So will the new Area function be a composition of SUM aggregation function and the a geometry are function or a competently standalone thing ? Cheers, On 08/30/2017 12:02 PM, Mauro Bartolomeoli wrote:
Hi, I would like to add a new aggregation function to the Aggregate process, in particular one to aggregate the area(s) of a feature geometries. Obviously it will work only if the aggregation attribute is a Geometry. In practice I will add a new "Area" value to the AggregationFunctions enum and implement the related visitor to calculate the aggregation. Any objection / doubt / suggestion? -- Regards, Mauro Bartolomeoli ==GeoServer Professional Services from the experts! Visit http://goo.gl/it488V for more information.==Dott. Mauro Bartolomeoli@mauro_bartTechnical LeadGeoSolutions S.A.S.Via di Montramito 3/A55054 Massarosa (LU)Italyphone: +39 0584 962313fax: +39 0584 1660272http://www.geo-solutions.ithttp://twitter.com/geosolutions_it------------------------------------------------------- AVVERTENZE AI SENSI DEL D.Lgs. 196/2003 Le informazioni contenute in questo messaggio di posta elettronica e/o nel/i file/s allegato/i sono da considerarsi strettamente riservate. Il loro utilizzo è consentito esclusivamente al destinatario del messaggio, per le finalità indicate nel messaggio stesso. Qualora riceviate questo messaggio senza esserne il destinatario, Vi preghiamo cortesemente di darcene notizia via e-mail e di procedere alla distruzione del messaggio stesso, cancellandolo dal Vostro sistema. Conservare il messaggio stesso, divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od utilizzarlo per finalità diverse, costituisce comportamento contrario ai principi dettati dal D.Lgs. 196/2003. The information in this message and/or attachments, is intended solely for the attention and use of the named addressee(s) and may be confidential or proprietary in nature or covered by the provisions of privacy act (Legislative Decree June, 30 2003, no.196 - Italy's New Data Protection Code).Any use not in accord with its purpose, any disclosure, reproduction, copying, distribution, or either dissemination, either whole or partial, is strictly forbidden except previous formal approval of the named addressee(s). If you are not the intended recipient, please contact immediately the sender by telephone, fax or e-mail and delete the information in this message that has been received in error. The sender does not give any warranty or accept liability as the content, accuracy or completeness of sent messages and accepts no responsibility for changes made after they were sent or for other risks which arise as a result of e-mail transmission, viruses, etc. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ GeoTools-Devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
-- Regards, Nuno Oliveira == GeoServer Professional Services from the experts! Visit http://goo.gl/it488V for more information. == Nuno Miguel Carvalho Oliveira @nmcoliveira Software Engineer GeoSolutions S.A.S. Via di Montramito 3/A 55054 Massarosa (LU) Italy phone: +39 0584 962313 fax: +39 0584 1660272 http://www.geo-solutions.it http://twitter.com/geosolutions_it ------------------------------------------------------- AVVERTENZE AI SENSI DEL D.Lgs. 196/2003 Le informazioni contenute in questo messaggio di posta elettronica e/o nel/i file/s allegato/i sono da considerarsi strettamente riservate. Il loro utilizzo è consentito esclusivamente al destinatario del messaggio, per le finalità indicate nel messaggio stesso. Qualora riceviate questo messaggio senza esserne il destinatario, Vi preghiamo cortesemente di darcene notizia via e-mail e di procedere alla distruzione del messaggio stesso, cancellandolo dal Vostro sistema. Conservare il messaggio stesso, divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od utilizzarlo per finalità diverse, costituisce comportamento contrario ai principi dettati dal D.Lgs. 196/2003.The information in this message and/or attachments, is intended solely for the attention and use of the named addressee(s) and may be confidential or proprietary in nature or covered by the provisions of privacy act (Legislative Decree June, 30 2003, no.196 - Italy's New Data Protection Code).Any use not in accord with its purpose, any disclosure, reproduction, copying, distribution, or either dissemination, either whole or partial, is strictly forbidden except previous formal approval of the named addressee(s). If you are not the intended recipient, please contact immediately the sender by telephone, fax or e-mail and delete the information in this message that has been received in error. The sender does not give any warranty or accept liability as the content, accuracy or completeness of sent messages and accepts no responsibility for changes made after they were sent or for other risks which arise as a result of e-mail transmission, viruses, etc.
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