Land Use
100 percent coverage of a land use layer is not available for the City of Rochester. A new layer is developed through heads-up digitizing (Figure 3). Current land use, zoning, survey descriptions, and aerial photography were loaded into an ArcMap project. On-screen editing of the existing land use data reshapes polygons based on percent coverage of impervious structures. The features are then attributed by percent infiltration, or the difference of the impervious value from 100 (Appendix A). For example, a land use classified as ‘institutional’ (a church or school) has a percent impervious value of 45, and an infiltration value of 55. The boundary of the institutional property is outlined, and the entire polygon receives a 55 in the field for potential infiltration.