On 1 October 2010 18:12, andrzej zaborowski <[email protected]> wrote: > Hi, > > On 30 September 2010 20:27, Nick Austin <[email protected]> wrote: >> I'm a user of TWISST, a free service run by volunteers that sends >> tweets notifying the best viewing times for overhead passes of the >> International Space Station. Earlier today they put out a request for >> help via their web site: >> http://twisst.nl/timezones >> >> In summary they need volunteers to help program in LAMP (Mysql 5.1, PHP 5.2). >> >> If your too lazy to follow the link here's the first few paragraphs >> from the web site: >> >> ----- >> "To send people correct ISS-alerts, we need to know in which timezone >> they are. We need a script to tell us that." >> >> "To find out their timezone, we send peoples coordinates to the >> Geonames server. Geonames is an awesome service. However, sometimes >> Geonames is swamped with requests and then we don't get timezones (we >> could opt for a more stable paid subscription, but we don have any >> money to invest here). New followers then are left with UTC as their >> default timezone, which leads to confusion." >> >> "Also, sending requests to Geonames all the time causes a lot of data >> traffic. We would like to cut on our diet of data traffic." >> >> "So, we would like to figure out ourselves which timezone to use for >> certain coordinates. From what we gather, this is not impossible. It >> takes a map with the timezones of the world as polygons and a script >> to find out in which polygon a set of coordinates lies.:" >> --- >> >> It occurs to me that because OSM uses GeoNames that this would improve >> the chances of OSM requests succeeding, so everyone benefits. For >> further details see the link above. >> >> Once again, I am just a user of their service, I have no connection at >> all with TWISST. > > Checking if a point is inside a polygons is trivial, but is it what > they really want? Wouldn't just the longitude tell you the time > better than the timezone? > > E.g. offset_from_gmt = ((lon - 180) / 15) hours
oops, rather (lon / 15) hours _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
