[postgis-users] Timezone for a given lat/long

suraj birla surajbirla at gmail.com
Tue Apr 11 16:05:06 PDT 2017


I imported timezone shapefile into postgis to get the timezone for the
lat/lon.

We have postgis on Greenplum with 32 segment and  running postgis query to
get TZ for 100K records takes around 70-90 secs.

I've index on geom table on both tz_world and source table .

Question : Whether 70-90 second to get TZ from tz_world table is good for
100K records on a 32 segment cluster?

2. Another requirement we have is to show 3 digit timezone code( for eg,
PST/PDT, EST/EDT , GMT , etc) for the derived tz_id (America/Los_Angeles)?






On Mon, Mar 27, 2017 at 9:47 PM, suraj birla <surajbirla at gmail.com> wrote:

> Thanks John and Jorge. It worked.
>
> On Wed, Mar 22, 2017 at 4:21 PM, John Abraham <jea at hbaspecto.com> wrote:
>
>> I use
>>
>> select tz.tzid from location
>>         join tz_world tz on st_within(location."locationPoint", tz.geom)
>>
>> with the tz_world shapefile that I'm 99% sure I got from
>>
>> *http://efele.net/maps/tz/world/ <http://efele.net/maps/tz/world/>*
>>
>>
>> --
>> John Abraham
>> jea at hbaspecto.com
>>
>> On Mar 22, 2017, at 3:23 PM, suraj birla <surajbirla at gmail.com> wrote:
>>
>> How to find the timezone for a given lat/long  using postgis?
>>
>> We have to requirement to fnd the local timezone for millions of records
>> which has  UTC timestamp and lat/long info.
>>
>> Google provide API but it's single request per call.. Not feasible for
>> milion records.
>>
>> Any suggestion?
>>
>> Thanks
>> Suraj
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