[OSRS-PROJ] lib call results differ from exec results

Gerald I. Evenden gerald.evenden at verizon.net
Mon Jul 14 13:43:35 EDT 2003


First of all, I can't see how you can use Alber's Equal Area
conic without specifying the standard parallels.

./lproj +proj=aea +ellps=clrk66
libproj4 system
<./lproj>:
projection initialization failure
cause: conic lat_1 = -lat_2
program abnormally terminated

Is what I get on my machine.  Of course we are not using the
same basic animal but it would seem to me that the software
used should complain about the usage parameters.  Without
knowing the parallels, no computations were possible!

Out of curiosity, what programming language is used below?

On Mon, 2003-07-14 at 12:52, Sharon Mingus wrote:
> I'm using the latest cvs libproj for transformations
> of coords and am having a problem.  I wrote this test
> program:
> 
> #include <proj_api.h>
> #include <stdio.h>
> 
> int main( int argc, char** argv )
> {
>         char *parms[] = {
>                 "proj=aea",
>                 "ellps=clrk66"
>         };
> 
>         projPJ pj = pj_init( 2, parms );
>         if( !pj )
>         {
>                 printf( "COULD NOT INIT\n" );
>                 return -1;
>         }
> 
>         projXY xy;
>         xy.u = atof( argv[1] ) * DEG_TO_RAD;
>         xy.v = atof( argv[2] ) * DEG_TO_RAD;
> 
>         printf( "FWD " );
>         xy = pj_fwd( xy, pj );
> 
>         printf( "%10.4f, %10.4f\n\n", xy.u, xy.v );
>         return 1;
> }
> 
> Then I do this:
> 
> $ ./proj_test -110.969 39.7621
> FWD -7422073.9419, 9122801.8182
> 
> $ echo "-110.969,39.7621" | proj +proj=aea
> +ellps=clrk66
> -11303100.31    7467691.88,39.7621
> 
> very different resulting coordinates.  Why is this?
> 
> then I do this:
> 
> $ echo "-11303100.31    7467691.88" | ./invproj
> +proj=aea +ellps=clrk66
> 110d58'8.4"W    0dN
> 
> Shouldn't it result with original lon/lat input?
> 
> Also, this mailing list has a search link that doesn't
> work.  Is there a way to search this archive?
> 
> Thanks
> sing.org/proj for subscription, unsubscription
	...
-- 
Gerald I. Evenden <gerald.evenden at verizon.net>

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