I wish JIRA wouldn't default to major - it would make those tags much more useful.
Simon Willnauer (JIRA) wrote: > [ > https://issues.apache.org/jira/browse/LUCENE-1815?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel > ] > > Simon Willnauer updated LUCENE-1815: > ------------------------------------ > > Priority: Minor (was: Major) > > I don't think this shouldn't be major! > > >> Geohash encode/decode floating point problems >> --------------------------------------------- >> >> Key: LUCENE-1815 >> URL: https://issues.apache.org/jira/browse/LUCENE-1815 >> Project: Lucene - Java >> Issue Type: Bug >> Components: contrib/spatial >> Affects Versions: 2.9 >> Reporter: Wouter Heijke >> Priority: Minor >> >> i'm finding the Geohash support in the spatial package to be rather >> unreliable. >> Here is the outcome of a test that encodes/decodes the same lat/lon and >> geohash a few times. >> the format: >> action geohash=(latitude, longitude) >> the result: >> encode u173zq37x014=(52.3738007,4.8909347) >> decode u173zq37x014=(52.373799999999996,4.890934) >> encode u173zq37rpbw=(52.373799999999996,4.890934) >> decode u173zq37rpbw=(52.373799999999996,4.8909329999999995) >> encode u173zq37qzzy=(52.373799999999996,4.8909329999999995) >> if I now change to the google code implementation: >> encode u173zq37x014=(52.3738007,4.8909347) >> decode u173zq37x014=(52.37380061298609,4.890934377908707) >> encode u173zq37x014=(52.37380061298609,4.890934377908707) >> decode u173zq37x014=(52.37380061298609,4.890934377908707) >> encode u173zq37x014=(52.37380061298609,4.890934377908707) >> Note the differences between the geohashes in both situations and the >> lat/lon's! >> Now things get worse if you work on low-precision geohashes: >> decode u173=(52.0,4.0) >> encode u14zg429yy84=(52.0,4.0) >> decode u14zg429yy84=(52.0,3.999999) >> encode u14zg429ywx6=(52.0,3.999999) >> and google: >> decode u173=(52.20703125,4.5703125) >> encode u17300000000=(52.20703125,4.5703125) >> decode u17300000000=(52.20703125,4.5703125) >> encode u17300000000=(52.20703125,4.5703125) >> We are using geohashes extensively and will now use the google code version >> unfortunately. >> > > -- - Mark http://www.lucidimagination.com --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
