- From: Gannon Dick <gannon_dick@yahoo.com>
- Date: Tue, 29 Jul 2014 10:45:20 -0700
- To: "andrea.perego@jrc.ec.europa.eu" <andrea.perego@jrc.ec.europa.eu>, "frans.knibbe@geodan.nl" <frans.knibbe@geodan.nl>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, Chris Beer <chris@codex.net.au>, ChrisLittle <chris.little@metoffice.gov.uk>
- Cc: "public-locadd@w3.org" <public-locadd@w3.org>, "public-egov-ig@w3.org" <public-egov-ig@w3.org>, public-lod <public-lod@w3.org>, "temporal@lists.opengeospatial.org" <temporal@lists.opengeospatial.org>, Piero Campalani <cmppri@unife.it>, Matthias Müller <matthias_mueller@tu-dresden.de>
On Tue, 7/29/14, Little, Chris <chris.little@metoffice.gov.uk> wrote: And I agree that transparency about calendar algorithms is an issue, not just in their book. This isone thing that I hope that an OGC Best Practice document could help, in however a small way. ============ Hi Chris, Maybe it is time to "go big" - Universal Coordinated Calendar Time (UTCT). In the near term, (this Julian Century) the Calendar has no unidentified shifts. We know about Leap Days and the Calendar is ignorant of Leap Seconds. So, it is possible. This presents a problem for Linked Data because even though Personal Identity is coupled to Occupation and Occupation is coupled to the Location of the Workplace, these are couplings not correlations. Mid-day, Noon, is a mean value, but one can't assume regression to the mean. At the Equator the "Authority" - Solar Noon - has a whopping 7 1/2 minute time shift. This is not hidden, but it is overwhelmed by the Equation of Time. The shifts, on a day-to-day basis do not accumulate to significance on a year-to-year basis. To determine coupling constants is a fools errand. e.g. http://www.rustprivacy.org/2014/balance/utct.jpg When people triangulate in their heads they use 3,4,5 triangles to keep the math easy. For this reason, the Axis length is 500%. All "shifts" (events which impact Work Life Balance) are vertical. Sorry, the "Day" indicator can't update automatically - it's a PDF. WDYT? Best, --Gannon (J.) Dick ;-) I'm not a commuter, I have a funny name. -----Original Message----- From: Gannon Dick [mailto:gannon_dick@yahoo.com] Sent: Thursday, July 24, 2014 5:24 PM To: andrea.perego@jrc.ec.europa.eu; frans.knibbe@geodan.nl; Simon.Cox@csiro.au; Chris Beer; Little, Chris Cc: public-locadd@w3.org; public-egov-ig@w3.org; public-lod; temporal@lists.opengeospatial.org; Piero Campalani; Matthias Müller Subject: Re: OGC Temporal DWG. Was: space and time Hi Chris, who wrote: One concern that I have is that we do not re-invent the wheel, and do nugatory work, hence this email. I do not envisage that we will need to do much with Calendars, which have been covered so well by Dershowitz and Reingold. ===================================== No question the quality of the issue coverage (Calendars) is first rate. However, the computations are not transparently self-evident and the references you cite in the Wiki are not available on-line - or are they ? 3. Calendrical Tabulations 1900-2200, Edward M. Reingold, Nachum Dershowitz. Hardcover: 636 pages. Publisher: Cambridge University Press (16 Sep 2002) Language: English ISBN-10: 0521782538 ISBN-13: 978-0521782531 4. Calendrical Calculations, Nachum Dershowitz, Edward M. Reingold. Paperback: 512 pages. Publisher: Cambridge University Press; 3 edition (10 Dec 2007) Language: English ISBN-10: 0521702380 ISBN-13: 978-0521702386 Accessability to "Wheels known to have been invented" is a Wiki issue, I think. --Gannon -------------------------------------------- On Thu, 7/24/14, Little, Chris <chris.little@metoffice.gov.uk> wrote: Subject: OGC Temporal DWG. Was: space and time To: "Gannon Dick" <gannon_dick@yahoo.com>, "andrea.perego@jrc.ec.europa.eu" <andrea.perego@jrc.ec.europa.eu>, "frans.knibbe@geodan.nl" <frans.knibbe@geodan.nl>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, "Chris Beer" <chris@codex.net.au> Cc: "public-locadd@w3.org" <public-locadd@w3.org>, "public-egov-ig@w3.org" <public-egov-ig@w3.org>, "public-lod" <public-lod@w3.org>, "temporal@lists.opengeospatial.org" <temporal@lists.opengeospatial.org>, "Piero Campalani" <cmppri@unife.it>, "Matthias Müller" <matthias_mueller@tu-dresden.de> Date: Thursday, July 24, 2014, 9:36 AM #yiv4303497829 #yiv4303497829 -- .yiv4303497829EmailQuote {margin-left:1pt;padding-left:4pt;border-left:#800000 2px solid;}#yiv4303497829 Dear Colleagues, OGC started a Temporal Domain Working Group last year to address a number of problems in the geospatial domain. In particular, that time is usually just viewed as Yet Another Attribute of Features, rather than a first class coordinate. We agreed earlier this year, in Geneva, that the OGC Naming Authority would have a branch to register Temporal, and index based, Coordinate Reference Systems, and we agreed on the fundamental attributes that a CRS should have to be registered. We hope to produce a Best Practice document this year to help clarify many confusions between CRSs, notations, calendars, operations and calculations. I think that now we have a good enough understanding of the underlying conceptual issues and current geospatial standards. We have been accumulating info on an open wiki http://external.opengeospatial.org/twiki_public/TemporalDWG/WebHome and discussing via our mailing list, though we are not very disciplined about it. One concern that I have is that we do not re-invent the wheel, and do nugatory work, hence this email. I do not envisage that we will need to do much with Calendars, which have been covered so well by Dershowitz and Reingold. Best wishes, Chris Chris Little Co-Chair, OGC Meteorology & Oceanography Domain Working Group Co-Chair, OGC Temporal Domain Working Group IT Fellow - Operational Infrastructures Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom Tel: +44(0)1392 886278 Fax: +44(0)1392 885681 Mobile: +44(0)7753 880514 E-mail: chris.little@metoffice.gov.uk http://www.metoffice.gov.uk I am normally at work Tuesday, Wednesday and Thursday each week
Received on Tuesday, 29 July 2014 17:45:48 UTC