[GRASS-dev] patch for v.voronoi/v.delaunay

[Hamish]

> Markus wrote:
> > It seems that the precision gets somewhere lost in
> > db_convert_column_value_to_string()
> > 
> > i.e. lib/db/dbmi_base/columnfmt.c
> > 
> > but I don't find where is is rounded.
> 
Hamish:
> lib/db/dbmi_base/valuefmt.c db_convert_value_to_string() does:
>         case DB_C_TYPE_DOUBLE:
>             sprintf (buf, "%lf",db_get_value_double(value));
>             G_trim_decimal(buf);
> 
> the %lf is rounding to %.6f?
> 
> maybe
> - "%lf"
> + "%.14f"
> 
> then let G_trim_decimal() remove any extra .00000s.
> 
> but maybe such noisy output is not always wanted. :-/
> (e.g. pretty output for d.what.vect tcl form)
> ?
> 
> FWIW v.out.ascii defaults to dp=8.
> 
> 
> for the v.colors script, SQL  "select * WHERE dbl_col = <FP number>" is
> always going to be problematic. 
> 
> the C way:
>  if( abs(test - value) < GRASS_EPSILON )


In the case of v.colors, the SQL set loop could be rewritten to avoid
this problem by matching to the cat number, not trying to logically match
the FP value.


Hamish



     
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