Polygon dynamic grid creation for a shape file

I have used QGIS Vector->ResearchTools-> Vector Grid to create a 1lat x 1 long grid for the landpolygon shape file (from osm).

Now, I am interested in creating dynamic grid for the original landpolygon shape file, i.e., close to the coastal-lines grid size should be .001 lat x .001 long and in the other areas existing grid size. Any suggestions? Thanks.