[GRASSLIST:4921] Re: Problems with importing polar data
morten at ngb.se
Sun Nov 10 01:02:44 EST 2002
On Sat, 9 Nov 2002, Eric G. Miller wrote:
> On Sat, Nov 09, 2002 at 09:56:25PM +0100, Morten Hulden wrote:
> > On Sat, 9 Nov 2002, Morten Hulden wrote:
> > > If proj does not have built-in default values for k0, x0 and y0 for this
> > > projection then src/libes/geo_init.c needs patching in order to add
> > > k-factor, false easting and northing.
> > I checked by running external proj with -V: Looks like proj really uses
> > k_0=0.9994, x_0=2000000 and y_0=2000000 as default values for UPS
> > projection.
> I'd think patching geo_init.c to set all the defaults and not ask except for
> lat_0 and south. I would just ask for south and then set lat_0
> appropriately, but g.setproj is too scary for words... Still requires
> user to know to use 90/-90 and n/y for south?, respectively...
also found out proj ignores lat_0 value in ups projection. so simplified
patch below. no need to ask for latitude at all and no need to touch the
the patch is purely cosmetic to make PROJ_INFO display real values used by
proj - ups projection should work correctly as is, even if values
PROJ_INFO are misleading.
better take this discussion over to developers' list.
--- geo_init.c 2002-06-16 17:29:25.000000000 +0200
+++ geo_init.c_new 2002-11-10 06:57:09.000000000 +0100
@@ -1150,11 +1150,16 @@
TABLE[UPS][LON0].ask = 1;
TABLE[UPS][LON0].def_exists = 1;
- TABLE[UPS][LON0].deflt = 20.0;
+ TABLE[UPS][LON0].deflt = 0.0;
- TABLE[UPS][LAT0].ask = 1;
- TABLE[UPS][LAT0].def_exists = 1;
- TABLE[UPS][LAT0].deflt = 55.0;
+ TABLE[UPS][KFACT].def_exists = 1;
+ TABLE[UPS][KFACT].deflt = 0.9994;
+ TABLE[UPS][X0].def_exists = 1;
+ TABLE[UPS][X0].deflt = 2000000.0;
+ TABLE[UPS][Y0].def_exists = 1;
+ TABLE[UPS][Y0].deflt = 2000000.0;
TABLE[UPS][SOUTH].ask = 1;
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