Sugar cane yield mapping improves the efficiency of sugar cane farming with benefits to both sugar producers and consumers. The improved database access system comprises a thin client interface layer, an integration layer, and a data layer made up of a plurality of disparate databases. Thus, according to the invention, the removal of the surface material formed on a surface of a resin substrate by coating or adhesive bonding can be carried out in enhanced efficiency, environment safety and processing capacity. A high resolution flood level elevation map is generated by interpolating flood level elevation from the selected points.