Since the early 1980's the EROS Alaska Field Office (AFO) has been involved in the acquisition, classification, and analysis of digital land cover data over the State of Alaska, and to a limited extent, northwestern Canada and Wrangle Island, Russia. The digital data currently covers approximately 77% of the land and water within the boundaries of the State of Alaska. These data are currently being made available via the AFO web site to land managers and researchers who may be interested in land cover conditions over various portions of Alaska. The land cover maps as a result of digital analysis of Landsat multispectral scanner, Landsat thematic mapper, and SPOT multispectral scanner satellite data. Some data however, are missing from the database due to data degradation on storage media or loss of data tapes, although a limited number of hard copy map products may be in existence, for example, U.S. Forest Service land cover data for southeast Alaska. The land cover data are stored online in a series of directories and are available via the web. Each directory name is indicative of the area for which the land cover data exists. Some directories connote a U.S. Geological Survey 1:250,000 quadrangle (for example, anchorage_int), while others indicate a particular project area (for example, anwr represents Arctic National Wildlife Refuge) or the agency responsible for producing the data. For example, nowitna.fws indicates that the data were produced for the U.S. Fish and Wildlife Service. Directories with an '_int' suffix denote that the data correspond to the Interim Landcover Mapping project. Each directory contains five files with the following extensions: .bil, .blw, .hdr, .prj, and .stx. As a group, one or more of the files can be read by most image analysis and GIS software packages. The .bil file contains the binary raster land cover data and the others are ASCII files. The .bil file does not contain any header or footer records, and can be easily imported into image processing software by using the information contained in the .blw and .hdr files. The .blw file provides pixel size information as well as the upper left corner coordinate. The .hdr contains number of rows and columns of the data set, as well as band format (band interleave). The .prj file gives projection information, and the .stx file gives information on minimum/maximum/ mean values of the data. Projection parameters for the data sets are either in Universal Transverse Projection (UTM) or Alaska Albers Equal Area Conic.

Updated January, 2022BROOD AREA: Areas supporting sage grouse broods. This generally includes wet areas such as meadows, springs, ponds and streams which all function as important brood rearing sites. To be mapped as a 200m (.124 mile) buffer zone around the edges of such wet sites. HISTORIC HABITAT: Areas where viable populations have not occurred in five years or more. OVERALL RANGE: An area which encompasses all mapped seasonal activity areas within the observed range of a population of sage grouse. PRODUCTION AREA: An area that would include the majority of important sage grouse nesting habitat. Mapped as a buffer zone of two miles around an active lek. SEVERE WINTER: That part of the winter range where 90 percent of the individuals are located when annual snowpack is at its' maximum and/or temperatures are at a minimum in the two worst winters out of ten. The winters of 1983-84, or 96-97 are good examples. WINTER RANGE:Observed winter range.This information was derived from Colorado Parks and Wildlife field personnel. Data was captured by digitizing through a SmartBoard Interactive Whiteboard using topographic maps and NAIP imagery at various scales (Cowardin, M., M. Flenner. March 2003. Maximizing Mapping Resources. GeoWorld 16(3):32-35). These data are updated on a four year rotation with one of the four Colorado Parks and Wildlife Regions updated each year. These data are not updated on a statewide level annually.PRIORITY AND GENERAL HABITATSummaryThe priority habitat map and data were developed as part of the BLM National Planning Strategy for Greater sage-grouse. These data provide a biological tool for planning in sage-grouse habitats. These maps depict Priority and General Habitats within occupied range in Colorado. In February 2016, the Associated Governments of Northwest Colorado (AGNC) hired a consultant (Olsson) to help further refine CPW’s greater sage-grouse habitat maps in Northwest Colorado. The Olsson consultant team, have utilized CPW’s contemporary and rigorous habitat models and developed their own to produce revised PHMA and GHMA habitat data. These spatial datasets (i.e., habitat maps) are specifically designed to meet the management intent of the ARMPA and have been produced for formal submittal to the BLM for incorporation into Northwest Colorado Land and Resource Management Plans. LINKAGESThis dataset identifies linkage areas between sage-grouse populations across GrSG range in Colorado. It is assumed the habitat linkages will allow for movement between populations and will decrease the probability of extinction of the species by stabilizing population dynamics. These linkages should be considered only as potential areas for movements between populations. The linkage dataset was created by mapping efforts of the CPW biologists for the statewide conservation plan in 2005, and further refined in early 2012. The linkages were delineated based on a selection of vegetation classes in the Colorado Basin-wide dataset. Habitat within linkages is composed of a mosaic of contrasting land forms, landcover types, and land uses. They are a heterogeneous landscape, within the historical range of GrSG, composed of isolated patches of landcover types frequently used by sage-grouse. Vegetation classes used contain current or historic sagebrush communities (e.g., piñon-juniper -sagebrush mix). Therefore, linkages are comprised of a non-contiguous and patchy mix of vegetation classes.

The Innoko National Wildlife Refuge digital data sets contain land cover classifications derived from Landsat MSS data, and elevation, slope and aspect data derived from DEM data. Data can be keyed on a U.S. Geological Survey 1:250,000 quadrangle basis. Spatial referencing is from 50 meter grid cells and data source is Landsat MSS data and Digital Elevation Model (DEM) data. This data set contains 113 records. The amount of storage required varies by storage medium and selected area. The file structure is sequential. Data are available online.

    The data is organized by 7 1/2 ' or 15 ' quads. General area covered: 62 to 64
    north to 155 to 45' to 160 to 15' west.

This digital data set contains land cover classifications (for the Upper Kuskokwim River Resource Management Area, Alaska) was derived from Landsat 4 MSS data, and elevation, slope and aspect data derived from DEM data. Data can be keyed on a U.S. Geological Survey 1:250,000 quadrangle. Data source is Landsat 4 MSS data and Digital Elevation Model (DEM) data. The data set contains 21 records. Storage required varies by storage medium and selected area. The file structure is sequential. Data are available online.

 General area covered: 634' north to 15657' west to 6515' north to 16053' west. 
 Dataset was developed through a cooperative program between the Bureau of Land
 Management (BLM) and the U.S. Geological Survey.