Yukon-Charley/Black River/Fortymile Earth Cover Classification

The Bureau of Land Management (BLM)-Alaska and Ducks Unlimited, Inc. (DU) have been cooperatively mapping wetlands and associated uplands in Alaska using remote sensing andgeographic information system (GIS) technologies since 1988. The National Park Service (NPS) has also had an ongoing mapping effort for their lands with the goal of mapping all Parks in Alaska. The goal of this project was to continue the mapping effort for both the BLM and NPS while reducing the overall cost by simultaneously mapping the Yukon-Charley Rivers National Preserve its surrounding environs and the Black River/Fortymile River BLM lands. One Landsat Thematic Mapper (TM) satellite scene (Path 66, Row 14, acquired August 20, 1991, shifted 40% south) was used to classify the project area into 30 earth cover categories. An unsupervised clustering or seeding technique was used to determine the location of field sites and a custom field data collection card and digital database were used to record field information. A helicopter was utilized to gain access to field sites throughout the project area. Global positioning system (GPS) technology was used both to navigate to pre-selected sites and record locations of new sites selected in the field. Data was collected on 316 field sites during a 10-day field season from August 3, 1997 through August 13, 1997. Approximately 40% (134) of these field sites were set aside for accuracy assessment. The field data collected in 1997 was supplemented with field data collected by the NPS in 1988 and 1990 for unrelated projects. The NPS data provided an additional 54 training sites and 112 accuracy assessment sites. Twenty-five accuracy assessment sites for earth cover classes not visited in the field (clear water, turbid water and snow) were obtained through photo interpretation. A modified supervised/unsupervised classification technique was performed to classify the satellite imagery. The classification scheme for the earth cover inventory was based on Viereck et al. (1992) and revised through a series of meetings coordinated by the BLM-Alaska and DU. The overall accuracy of the major categories was 80%.