On Mon, 18 Oct 2004, Markus Neteler wrote:
Roger,
following your suggestion I have added a warning in r.in.bin
to check if EW and NS differ significantly (indicating that
probably east= and west= are confused).
Not sure if I am doing that right, patch below.
Looks good to me, though 1:50 is quite liberal, given that most raster
grids are not far from square, maybe 1:10? I don't think there is any
other way round user error in this case given that east-west in lat-long
is, well, round. Maybe a comment on the man page: add to east and west:
"Eastern limit of geographic region (in projected coordinates must be east
of the west parameter value, but in geographical coordinates will wrap
around the globe; user errors can be detected by comparing the ewres and
nsres values of the imported map layer carefully)"
"Western limit of geographic region (in projected coordinates must be west
of the east parameter value, but in geographical coordinates will wrap
around the globe; user errors can be detected by comparing the ewres and
nsres values of the imported map layer carefully)"
and give an example, maybe the output og g.region when the first example
is run with east and west reversed? This was a bad trap, maybe the man
page is the best place for advice?
Roger
Markus
On Mon, Oct 18, 2004 at 02:35:27PM +0200, grass@intevation.de wrote:
> Author: markus
>
> Update of /grassrepository/grass/src/raster/r.in.bin
> In directory doto:/tmp/cvs-serv22175
>
> Modified Files:
> main.c
> Log Message:
> added test for LatLong in case the resolution differs significantly (two ways to go around the globe in E/W direction...)
>
> Index: main.c
> ===================================================================
> RCS file: /grassrepository/grass/src/raster/r.in.bin/main.c,v
> retrieving revision 1.14
> retrieving revision 1.15
> diff -u -d -r1.14 -r1.15
> --- main.c 18 Oct 2004 12:23:14 -0000 1.14
> +++ main.c 18 Oct 2004 12:35:25 -0000 1.15
> @@ -455,6 +455,9 @@
> x_s = (short *) x_v;
> x_c = (char *) x_v;
>
> + if( cellhd.proj == PROJECTION_LL && cellhd.ew_res/cellhd.ns_res > 50. ) /* TODO: find a reasonable value */
> + G_warning("East-West (ewres: %f) and North-South (nwres: %f) resolution differ significantly. Did you assign east= and west= correctly?", cellhd.ew_res, cellhd.ns_res);
> +
> fprintf(stderr, "Percent Complete: ");
> for (row = 0; row < grass_nrows; row++)
> {
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--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@nhh.no