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Like Float.compare(a. b) and Double.compare(a, b) 2015-04-21 17:14 GMT+03:00 John Caron <caron@xxxxxxxx>: > ok, and you always have to compare floats with a tolerance, not exact. ive > been bitten many times by that. > > John > > On Tue, Apr 21, 2015 at 8:02 AM, Daniele Romagnoli > <daniele.romagnoli@xxxxxxxxxxxxxxxx> wrote: >> >> Hi John, >> thanks for your reply. >> >> The problem I have with this is that I'm setting up a predefined set of >> custom CoordinateReferenceSystem definitions: >> as an instance, a LambertConformal projection where standard parallels is >> 25. >> Then, I'm parsing the gridMapping attributes in order to try to recognize >> a known custom CRS and I'm getting no matches since it is expecting 25 >> instead of 25.00002. (CRS matching checks use WKT parsing). >> >> In the meantime, I will investigate more on this. >> Cheers, >> Daniele >> >> >> >> == >> GeoServer Professional Services from the experts! Visit >> http://goo.gl/NWWaa2 for more information. >> == >> >> Ing. Daniele Romagnoli >> Senior Software Engineer >> >> GeoSolutions S.A.S. >> Via Poggio alle Viti 1187 >> 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. >> >> >> >> On Tue, Apr 21, 2015 at 2:15 AM, John Caron <caron@xxxxxxxx> wrote: >>> >>> Hi Daniele: >>> >>> GRIB projection info is stored in the GRIB file in (at most) 3 bytes, so >>> has a maximum precision of 24 bits. >>> >>> Im surprised that you are seeing a problem, it seems unlikely that a >>> roundoff in the low order bit of a float should matter. >>> >>> But theres not really a good reason that we couldnt use doubles if >>> needed. >>> >>> John >>> >>> >>> On Mon, Apr 20, 2015 at 3:45 AM, Daniele Romagnoli >>> <daniele.romagnoli@xxxxxxxxxxxxxxxx> wrote: >>>> >>>> Hi List, >>>> I'm using NetCDF Java 4.5.5. >>>> I have noticed that when computing the LambertConformal projection >>>> components (such as latin1, latin2...) in Grib1Gds I'm getting: >>>> >>>> latin1 = 25.00001 >>>> latin2 = 25.05002 >>>> dx1 = 13.545001 >>>> dy1 = 13.545001 >>>> >>>> Instead of: >>>> latin1 = 25 >>>> latin2 = 25.05 >>>> dx1 = 13.545 >>>> dy1 = 13.545 >>>> >>>> Plus, I'm getting some additional precision loss when extracting these >>>> attributes >>>> from the associated grid_mapping variable, as numbers (double values). >>>> I will surely investigate more on the topic to become more confident >>>> with that code and I will read again about representation errors on >>>> floating >>>> point arithmetics so my question could sounds trivial: Why these variables >>>> and scale constants are floats instead of doubles? (is it for size and >>>> performance issues?) >>>> >>>> Regards, >>>> Daniele >>>> >>>> >>>> >>>> >>>> == >>>> GeoServer Professional Services from the experts! Visit >>>> http://goo.gl/NWWaa2 for more information. >>>> == >>>> >>>> Ing. Daniele Romagnoli >>>> Senior Software Engineer >>>> >>>> GeoSolutions S.A.S. >>>> Via Poggio alle Viti 1187 >>>> 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. >>>> >>>> >>>> >>>> _______________________________________________ >>>> netcdf-java mailing list >>>> netcdf-java@xxxxxxxxxxxxxxxx >>>> For list information or to unsubscribe, visit: >>>> http://www.unidata.ucar.edu/mailing_lists/ >>> >>> >> > > > _______________________________________________ > netcdf-java mailing list > netcdf-java@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/
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