[tz] How good is pre-1970 time zone history represented in TZ database?
Alois Treindl
alois at astro.ch
Thu Jun 4 05:37:36 UTC 2020
Just to be clear: The statistics below represent the the geographical
distribution of the birth places of users of astro.com, i.e. of people
with an active interest in astrology.
The figures do not relate to the distribution of general population
figures, or state surfaces or anything like that.
On 03.06.20 12:01, Alois Treindl wrote:
>
> It is known that pre-1970 time zone history is represented in TZ
> database only for the cities which define the zone names.
> Other areas of countries are often not correctly represented in TZ
> database before 1970.
>
> The worst are the USA and Canada, because there, in many states, the
> authority about daylight time adherence was in the hands of counties
> or towns, up to the Uniform Timezone Act of 1967.
>
> I am personally responsible for providing correct timezone history for
> the astrological service company Astrodienst AG in Switzerland, which
> runs among other things the website www.astro.com
>
> As source for timezone history we use, besides TZ database, the
> International and American Atlas by Thomas Shanks, and our own research.
>
> The data we have are still far from perfect, because many local
> details of time zone and daylight saving time use are unknown,
> especially in the US and Canada.
>
> We have about 25 million birth data records in our database.
>
> I have analyzed to what extent TZ database represents the time zone
> information correctly, for these data.
>
> I think the results are of some interest for the TZ community.
>
> The overall sums are:
>
> tz_count 24'674'767 data records, 100%
> tz_irange 23'675'636 in time range and region which TZ covers
> correctly, 96%
> tz_good 736'769 in time range and region where TZ is
> unreliable, but correct, 3%
> tz_bad 262'362 in time range and region where TZ database
> gives false result. 1%
>
> This means that only 1% of our astrological charts would be false, if
> we used TZ database only, without any extra time zone history sources.
>
> More details by country or US/Canada state.
> state count in_range % good % bad %
> USA
> AK (US) 19889 99.6 0.0 0.3 Alaska
> AL (US) 64975 78.6 13.3 8.1 Alabama
> AR (US) 43159 77.2 12.7 10.0 Arkansas
> AZ (US) 96545 97.9 2.0 0.0 Arizona
> CA (US) 981941 100.0 0.0 0.0 California
> CO (US) 107204 99.5 0.5 0.0 Colorado
> CT (US) 89273 95.8 4.2 0.0 Connecticut
> DC (US) 58401 85.7 13.1 1.1 District
> of Columbia
> DE (US) 14376 91.3 8.5 0.3 Delaware
> FL (US) 241083 89.0 6.5 4.5 Florida
> GA (US) 114613 85.8 7.1 7.2 Georgia (US)
> HI (US) 44070 100.0 0.0 0.0 Hawaii
> IA (US) 50194 72.7 17.1 10.2 Iowa
> ID (US) 23877 92.2 6.4 1.4 Idaho
> IL (US) 267459 90.4 9.5 0.1 Illinois
> IN (US) 88263 76.8 21.6 1.6 Indiana
> KS (US) 45462 74.4 15.0 10.6 Kansas
> KY (US) 56494 74.6 12.5 12.9 Kentucky
> LA (US) 76017 80.3 11.9 7.8 Louisiana
> MA (US) 193439 87.1 12.9 0.1 Massachusetts
> MD (US) 91577 91.2 8.1 0.7 Maryland
> ME (US) 31873 96.8 2.8 0.5 Maine
> MI (US) 185568 86.0 13.3 0.7 Michigan
> MN (US) 95725 75.0 17.0 7.9 Minnesota
> MO (US) 91038 79.4 14.4 6.2 Missouri
> MS (US) 28859 70.0 20.4 9.6 Mississippi
> MT (US) 19767 73.7 24.7 1.5 Montana
> NC (US) 106991 82.9 10.2 6.9 North Carolina
> ND (US) 12427 71.5 17.5 10.9 North Dakota
> NE (US) 28670 69.1 18.2 12.7 Nebraska
> NH (US) 23707 91.2 8.2 0.6 New Hampshire
> NJ (US) 190614 99.6 0.3 0.1 New Jersey
> NM (US) 42651 80.6 18.4 0.9 New Mexico
> NV (US) 36053 99.4 0.4 0.3 Nevada
> NY (US) 628944 96.8 3.0 0.1 New York
> OH (US) 191745 73.9 18.3 7.8 Ohio
> OK (US) 55229 73.7 16.5 9.8 Oklahoma
> OR (US) 98166 87.1 9.8 3.1 Oregon
> PA (US) 228064 89.8 9.7 0.6 Pennsylvania
> PR (US) 37149 100.0 0.0 0.0 Puerto Rico
> RI (US) 26089 97.1 2.8 0.1 Rhode Island
> SC (US) 40233 82.9 10.0 7.1 South Carolina
> SD (US) 12863 72.7 18.6 8.7 South Dakota
> TN (US) 75125 82.9 9.3 7.8 Tennessee
> TX (US) 327328 83.3 9.8 6.9 Texas
> UT (US) 48909 82.7 16.2 1.1 Utah
> VA (US) 109591 85.5 10.1 4.4 Virginia
> VT (US) 17598 86.4 12.7 0.9 Vermont
> WA (US) 159835 84.8 11.9 3.3 Washington
> WI (US) 85917 75.5 18.5 5.9 Wisconsin
> WV (US) 22800 72.7 20.3 7.0 West Virginia
> WY (US) 8962 75.1 23.9 0.9 Wyoming
>
>
> Canada
> AB (CAN) 64249 97.9 2.0 0.1 Alberta
> BC (CAN) 99214 98.0 2.0 0.0 British
> Columbia (CAN)
> MB (CAN) 21563 69.8 27.5 2.6 Manitoba (CAN)
> NB (CAN) 10438 89.0 8.3 2.7 New
> Brunswick (CAN)
> NF (CAN) 7329 98.4 1.2 0.4
> Newfoundland (CAN)
> NS (CAN) 18829 75.4 16.3 8.2 Nova
> Scotia (CAN)
> NT (CAN) 1137 80.7 0.0 19.3 Northwest
> Territories (CAN)
> ON (CAN) 239755 86.3 12.4 1.3 Ontario (CAN)
> PE (CAN) 2036 80.0 16.1 3.9 Prince
> Edward Island (CAN)
> QU (CAN) 126300 88.4 9.8 1.8 Quebec (CAN)
> SK (CAN) 24390 78.2 12.4 9.5
> Saskatchewan (CAN)
> YK (CAN) 932 100.0 0.0 0.0 Yukon
> Territories (CAN)
>
> Other countries with significant issues in TZ database, only those
> with > 1% bad results
> BY 13966 97.1 1.2 1.7 Belarus
> CAR 268 33.2 0.4 66.4 Central
> African Repub
> CHINA 214617 96.0 2.4 1.6 China
> CONGO 1026 49.9 0.0 50.1 Congo
> (Brazaville)
> GABON 704 47.7 0.0 52.3 Gabon
> GUAM 3613 45.6 0.0 54.4 Guam
> INDSA 51950 97.2 0.8 2.0 Indonesia
> NIGER 294 76.9 3.7 19.4 Niger
> NIRE (UK) 16228 97.1 0.7 2.1 Northern
> Ireland
> RU 177880 89.4 8.5 2.1 Russian
> Federation
> SUDAN 2495 0.0 0.0 100.0 Sudan
> (?? my be my fault)
> TAAF 2 0.0 0.0 100.0 French
> Kerguelen Islands
> TANZ 4162 68.3 30.2 1.5 Tanzania
> TOK 17 41.2 0.0 58.8 Tokelau
> UA 71260 95.9 2.4 1.7 Ukraine
> VIET 299630 97.6 0.8 1.6 Vietnam
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mm.icann.org/pipermail/tz/attachments/20200604/164bae97/attachment-0001.html>
More information about the tz
mailing list