Knut, That makes no sense - nobody does area calculations on lat/long (i.e. the geographical graticule), you must first project the lat/long data into a suitable projection and then calculate areas.
For smaller areas (e.g. small and medium-sized countries) you would typically use UTM (Transverse Mercator), but that is completely inappropriate for larger areas. Just think about it: on a standard global Mercator projection, Greenland looks twice as big as India - whereas the reality is that India has a 50% larger area than Greenland. Besides, if you do calculate areas using lat/long and decimal degrees, the "result" will be squared decimal degrees - which means nothing to anybody. Regards Calle On 25 April 2016 at 15:16, Knut Staring <knu...@gmail.com> wrote: > AFAIK all coordinates are lat/lon, so I suppose that also goes for the > area calculation. > > Knut > > On Mon, Apr 25, 2016 at 3:05 PM, Calle Hedberg <calle.hedb...@gmail.com> > wrote: > >> Lars, >> >> Thanks - it is downloading >> >> One initial question re GIS area calculations: what projection is used >> for the calculation? >> >> regards >> calle >> >> On 25 April 2016 at 14:53, Lars Helge Øverland <l...@dhis2.org> wrote: >> >>> >>> >>> On Mon, Apr 25, 2016 at 2:39 PM, Calle Hedberg <calle.hedb...@gmail.com> >>> wrote: >>> >>>> Hi, >>>> >>>> Good stuff - will go through it in more detail, but please note that >>>> trying to download the 2.23 demo database gives an error (file not found). >>>> >>>> regards >>>> Calle >>>> >>> >>> >>> Right - fixed now. >>> >>> >>> -- >>> Lars Helge Øverland >>> Lead developer, DHIS 2 >>> University of Oslo >>> Skype: larshelgeoverland >>> http://www.dhis2.org <https://www.dhis2.org/> >>> >>> >> >> >> -- >> >> ******************************************* >> >> Calle Hedberg >> >> 46D Alma Road, 7700 Rosebank, SOUTH AFRICA >> >> Tel/fax (home): +27-21-685-6472 >> >> Cell: +27-82-853-5352 >> >> Iridium SatPhone: +8816-315-19119 >> >> Email: calle.hedb...@gmail.com >> >> Skype: calle_hedberg >> >> ******************************************* >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~dhis2-devs >> Post to : dhis2-devs@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~dhis2-devs >> More help : https://help.launchpad.net/ListHelp >> >> > > > -- > Knut Staring > Dept. of Informatics, University of Oslo > Norway: +4791880522 > Skype: knutstar > http://dhis2.org > -- ******************************************* Calle Hedberg 46D Alma Road, 7700 Rosebank, SOUTH AFRICA Tel/fax (home): +27-21-685-6472 Cell: +27-82-853-5352 Iridium SatPhone: +8816-315-19119 Email: calle.hedb...@gmail.com Skype: calle_hedberg *******************************************
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