Minnesota Land Cover, 1991–1992

This map depicts classes of vegetative land cover as derived from Landsat Thematic Mapper imagery. This data layer was created for the federal Gap Analysis Program (GAP), a nationwide effort to prioritize and focus conservation work. Scene pairs of leaf-on and leaf-off Landsat imagery were classified into four hierarchical levels with 49 classes in the most detailed fashion, with a minimum mapping unit of one acre. For display purposes, the classes have been condensed to 11, and the smallest vegetation unit shown is approximately five acres.

The 10 Ecological Classification System (ECS) sections of Minnesota shown on this map played an important part in the classification effort. To minimize vegetation variation, classification iterations were limited to a single ECS section at a time (as well as scene boundary). Existing descriptions of each section provided a priori information to help image analysts improve the efficiency of their classification efforts and the vegetation classes they were targeting. Further refinements were made using an upland/lowland mask created from National Wetland Inventory data. To this day, the ecological section boundaries have proven to be an efficient and logical system for refining classification and spatial analysis efforts.

The result of the GAP project was the first comprehensive statewide vegetation data layer for Minnesota with a uniform vegetation typology and analysis protocol, an important step forward for spatial analysis efforts. The layer is frequently used as input to analyses such as forest change detection and insect and disease modeling.

The map was designed in ArcMap 8.1 and revised using ArcMap 9. The shaded relief image was created by merging the classified GAP polygons with digital elevation model shaded relief using the GRID tool. It was created on Dell Precision 330 workstation as well as a Sun Ultra 2 UNIX workstation.

Visit the Land Management Information Center—Minnesota Land Use and Cover Web site for more information.