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

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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