I've installed the qgis on ubuntu 12.04 following the instructions on http://hub.qgis.org/projects/quantum-gis/wiki/Download. I am trying to test the Python API and try to do the follwoing
from qgis.core import *
layer = QgsVectorLayer("coast.shp", "coast_shp", "ogr")
But layer.isValid()
returns false. Any ideas why it might happen?