Produire un document A4 paysage

\documentclass[a4paper,twocolumn,landscape,10pt]{article}

\usepackage[latin1]{inputenc}

\usepackage{geometry}
\geometry{dvips,left=2cm,right=1cm,top=3cm,bottom=0cm,noheadfoot}
\setlength{\columnseprule}{1.2pt}
	
\setlength{\textheight}{18cm}
\setlength{\textwidth}{27cm}

\addtolength{\voffset}{0.03cm}
\setlength{\headheight}{15pt}
\setlength{\headsep}{10pt}