[GRASS-user] azimuth of lines with v.to.db?

[Hamish]

Carlos wrote:
> > this doesn't:
> >
> > > echo "UPDATE Lineam_isobase SET ang_rad=atan2(dx,dy)" | db.execute
> > DBMI-DBF driver error:
> > SQL parser error:
> > in statement:
> > UPDATE Lineam_isobase SET ang_rad=atan2(dx,dy)
> >
> > Error in db_execute_immediate()
> >
> > ERROR: Error while executing: 'UPDATE Lineam_isobase SET
> >        ang_rad=atan2(dx,dy)

Martin wrote:
> Use instead of DBF e.g. pg driver, atan2() is not supported by DBF driver.

could you get the values of dx,dy to the shell with (v.)db.select then use awk
to do the math and send the result to db.execute?

Other DBs (SQLite, MySQL, Postgres,..) should support it directly.


Hamish


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