OGR buffer vector data. From http://goo.gl/TjjQk Via https://gist.github.com/jgomezdans/808194

buffer.py

#!/usr/bin/env python
#buffer.py
import sys
import os
from osgeo import ogr

def buffer(infile,outfile,buffdist):
    try:
        ds_in=ogr.Open( infile )
        lyr_in=ds_in.GetLayer( 0 )
        drv=ds_in.GetDriver()
        if os.path.exists( outfile ):
            drv.DeleteDataSource(outfile)
        ds_out = drv.CreateDataSource( outfile )
    
        lyr_out = ds_out.CreateLayer( lyr_in.GetLayerDefn().GetName(), lyr_in.GetSpatialRef(), ogr.wkbPolygon)
        for i in xrange ( lyr_in.GetLayerDefn().GetFieldCount() ):
            field_in = lyr_in.GetLayerDefn().GetFieldDefn( i )
            field_out = ogr.FieldDefn( field_in.GetName(), field_in.GetType() )   
            lyr_out.CreateField ( field_out )
    
        for feat_in in lyr_in:
            geom = feat_in.GetGeometryRef()
            feat_out = feat_in.Clone()
            feat_out.SetGeometry(geom.Buffer(float(buffdist)))
            lyr_out.CreateFeature(feat_out)
            del geom
        ds_out.Destroy()
    except:
        return False
    return True

if __name__=='__main__':
    usage='usage: buffer <infile> <outfile> <distance>'
    if len(sys.argv) == 4:
        if buffer(sys.argv[1],sys.argv[2],sys.argv[3]):
            print 'Buffer succeeded!'
            sys.exit(0)
        else:
            print 'Buffer failed!'
            sys.exit(1)
    else:
        print usage
        sys.exit(1)