[GRASS-user] Re: r.in.gdal oddity

Brian Oney zenlines at gmail.com
Thu Nov 3 06:28:25 EDT 2011

Hmmm, maybe just a suggestion, although it won't fix the current problem 
but to make the code better (I  hope)... because it apperas the if one 
has an imprecise 0-360 map that thing could go awry, which may justify 
another flag (if I may) or something similar to the few changes below.

     /* constrain to geographic coords */
     if (flag_l->answer&&  G_projection() == PROJECTION_LL) {
         if (cellhd.north>  90.) cellhd.north = 90.;
         if (cellhd.south<  -90.) cellhd.south = -90.;
         if (cellhd.east>  360.) cellhd.east = 360.;

	/* for the case of imprecise coordinates 0-360: if the difference is greater than 360 AND it is the "other" ll projection AND the cellhd.west is strange THEN set cellhd.west to  0*/
         if (cellhd.east - cellhd.west>  360.&&  cellhd.east>= 181.&&  cellhd.west<  0.) cellhd.west = 0.;

	/* maybe just one degree of imprecision allowed? */
	if (cellhd.east>  180.&&  cellhd.east<  181.) cellhd.east = 180.;
         if (cellhd.west<  -180.) cellhd.west = -180.;
         cellhd.ns_res = (cellhd.north - cellhd.south) / cellhd.rows;
         cellhd.ew_res = (cellhd.east - cellhd.west) / cellhd.cols;
         cellhd.ew_res3 = cellhd.ew_res;
         cellhd.ns_res3 = cellhd.ns_res;

         G_warning(_("Map bounds have been constrained to geographic "
             "coordinates. You will almost certainly want to check "
             "map bounds and resolution with r.info and reset them "
             "with r.region before going any further."));

I am not sure how to perform math operations in if-expressions in C, but 
above is the general idea.

Again, I doubt this will fix the r.in.gdal oddity, but it may improve 
the -l flag.

Notice that the resolution in the mentioned post is the same as my 
case... prob just a coincidence.


On 11/03/2011 07:21 AM, Markus Neteler wrote:
> On Thu, Nov 3, 2011 at 5:17 AM, Hamish<hamish_b at yahoo.com>  wrote:
>> Hi, coming to this thread a bit late, sorry if I miss the point;
>> I'll study the rest of the thread/situation better asap, but some
>> general comments--
>> Markus wrote:
>>>> Just force it to be 180W and 180E... I thought (the -l
>>>> flag) it is just a recent addition to GRASS 6.4, so maybe
>>>> it needs a some t.l.c...
>> AFAIK it is working as intended and without bugs.
> Please check then
> http://article.gmane.org/gmane.comp.gis.grass.user/41407
> Here I don't see that -l works.
> thanks
> Markus

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