EROS ALASKA FIELD OFFICE - ALASKAN LAND COVER DATA BASE
Since the early 1980s, the EROS Alaska Field Office (AFO) has been involved in the acquisition, classification, and analysis of vegetative land cover data over the State of Alaska, and to a limited extent, northwestern Canada and Wrangle Island, Russia. Recently, an attempt has been made to acquire the historical land cover data produced by the various State and Federal agencies in Alaska and make them available to land managers and researchers who may be interested in land cover conditions over various portions of Alaska. The data currently available consists of final land cover maps as a result of spectral classification of Landsat multispectral scanner, Landsat thematic mapper, or SPOT multispectral scanner satellite data. The data within this database currently covers approximately 70% of the land and water within the boundaries of the State of Alaska. It should be noted that data over some areas of the State are missing from the database due to data degradation on storage tape media or loss of data tapes, although a limited number of hard-copy map products may be in existence (e.g., southeast Alaska).
The land cover data are currently in a series of directories and associated files which are available via ftp. Each directory name is indicative of the area for which the land cover data exists. Some directories indicate a U.S. Geological Survey 1:250,000 quadrangle (e.g., anchorage_int), while others indicate a particular project area (e.g., anwr for Arctic National Wildlife Refuge). Also associated with some of the names is an indicator of the agency responsible for producing the data (e.g., nowitna.fws or U.S. Fish and Wildlife Service). Directories with an '_int' suffix indicate that the data correspond to Interim Land cover Mapping project as described by Shasby and Carneggie 1986 or Fitzpatrick-Lins and others 1989.
Each directory contains five files with the following extensions: .bil, .blw, .hdr, .prj, and .stx. As a group, the files are easily read by ARC/INFO GRID, with the resulting grid containing all of the georeference information. The .bil file contains the binary raster land cover data and can be read into almost any of the common image processing software packages. The .blw file gives 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 sequential or interleave). The .prj file gives projection information, and the .stx file gives information on minimum/maximum/ mean values of the data.
Fitzpatrick-Lins, K., Doughty, E.F., Shasby, M., and Benjamin, S., 1989. Alaska Interim Land Cover Mapping Program - Final Report, U.S. Geological Survey Open-File Report 89-128, Reston, Virginia.
Shasby, M., and Carneggie, D., 1986. Vegetation and terrain mapping in Alaska using Landsat MSS and digital terrain data, Photogrammetric Engineering and Remote Sensing 52:779-786.
Land Cover Class Legend
2 Cloud/Cloud Shadow
3 Open Needleleaf Forest
4 Mixed Forest
5 Broadleaf Forest
6 Subalpine Scrub
7 Lowland Scrub
8 Lichen-Dwarf Shrub Peatland
9 Dwarf Shrub-Graminoid Peatland
10 Graminoid-Dwarf Shrub Peatland
11 Graminoid Tussock Dwarf Shrub Peatland
12 Erect Dwarf Shrub Heath
13 Prostrate Dwarf Shrub Heath
14 Dwarf Shrub Boulderfield
15 Forb Marsh
16,17 Graminoid Marsh
18 Graminoid Meadow
19 Wet Graminoid Bog
20 Mesic Graminoid Bog
21 Scarcely Vegetated Mudflats
22 Scarcely Vegetated Scree
23 Clear Onshore Water
24,25 Moderately Turbid Onshore Water
26,27 Very Turbid Onshore Water
28 Clear Offshore Water
29,30 Moderately Turbid Offshore Water
31 Very Turbid Offshore Water
32 No Data
33 Refuge Boundary (not on all maps)
***** Spatial Reference Information (Beg) *****
Number of Columns: 3650
Number of Rows: 2700
Pixel Resolution (m): 50
Data Type: byte
***** Spatial Reference Information (End) *****