National Land Cover Database (NLCD) 2011 - Alaska

Dates

Publication Date: 2020-02-21
Start Date: 1998-06-07
End Date: 2014-09-01

Citation

U.S. Geological Survey, 2014, National Land Cover Database (NLCD) 2011 Land Cover Conterminous United States (ver. 2.0, May 2024): U.S. Geological Survey data release, https://doi.org/10.5066/P97S2IID.

Summary

This update to the Alaska National Land Cover Database (NLCD) 2016 replaces the files dated 20200213. In this update the landcover footprint was extended along the northern coast to include the islands that were missed in previous versions, and several duplicate roads (offset by 1 or 2 pixels) were removed on the Aleutian Islands. The Alaska National Land Cover Database 2016 was created using change detection between the nominal dates of 2011 and 2016 utilizing Google Earth engine composites of Landsat imagery. Traditionally, previous classifications of Alaska used path row data and spectral comparisons between path rows along with ancillary data to derive areas of change. Alaska has many challenges for land cover classification, with [...]

Summary

This update to the Alaska National Land Cover Database (NLCD) 2016 replaces the files dated 20200213. In this update the landcover footprint was extended along the northern coast to include the islands that were missed in previous versions, and several duplicate roads (offset by 1 or 2 pixels) were removed on the Aleutian Islands. The Alaska National Land Cover Database 2016 was created using change detection between the nominal dates of 2011 and 2016 utilizing Google Earth engine composites of Landsat imagery. Traditionally, previous classifications of Alaska used path row data and spectral comparisons between path rows along with ancillary data to derive areas of change. Alaska has many challenges for land cover classification, with the largest of these being a very short “leaf on” imagery season for acceptable phenology. This is compounded by persistent cloud cover during this growing season, and increasing terrain shadow and sun angle problems outside of this season. For this reason, the timeframe of 10 years was needed for the first update to the Alaska land cover in order to have enough acceptable imagery between these 2001 and 2011 nominal dates that met these criteria in order to provide reasonable change detection. For 2016, there was not enough complete path row imagery to do this similar change detection. Google Earth engine was employed to create a composite imagery mosaic that uses much smaller pieces of Landsat imagery to create a complete Landsat imagery snapshot used to create change detection between 2011 and 2016. Although this composite technique is not as scientifically rigorous as utilizing direct Landsat imagery, it was the only method available to us during production that would allow completion of change detection in the desired five year timeframe. The original published 2001 and 2011 Alaska NLCD classifications are generally unchanged, except for slight updates in the northern part of the state to remove perennial ice and snow that were a result of lack of suitable imagery in the 2001 timeframe representing minimum snow and ice extent. See the 2001 and 2011 Land Cover products for the specific metadata process steps associated with the creation of those datasets.

Contacts

Point of Contact :: Customer Services Representative, U.S. Geological Survey
Process Contact :: Customer Services Representative, U.S. Geological Survey
Originator :: U.S. Geological Survey
Metadata Contact :: Customer Services Representative, U.S. Geological Survey
Publisher :: U.S. Geological Survey
Author :: Jon Dewitz
USGS Mission Area :: Core Science Systems
SDC Data Center :: Earth Resources Observation and Science (EROS) Center
Distributor :: U.S. Geological Survey - ScienceBase

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NLCD_2011_LandCover_AK_20200724.xml “Summary metadata” Original FGDC Metadata	View	36.16 KB	application/fgdc+xml
ak_nlcd_2011_landcover_1_15_15.zip “AK 2011 Land Cover (older version)”		242.77 MB	application/zip
ak_nlcd_2011_landcover_change_pixels_1_15_15.zip “AK 2011 Land Cover change pixels”		27.03 MB	application/zip
NLCD_2001_to_2011_Impervious_Change_Pixels_AK_20200724.zip “AK 2001-2011 Impervious change pixels”		185.71 KB	application/zip
NLCD_2001_to_2011_Land_Cover_Change_Pixels_AK_20200724.zip “AK 2001-2011 Land Cover change pixels”		50.14 MB	application/zip
NLCD_2011_Impervious_AK_20200724.zip “AK 2011 Impervious”		1.77 MB	application/zip
NLCD_2011_Impervious_Descriptor_AK_20200724.zip “AK 2011 Impervious descriptor”		876.64 KB	application/zip
NLCD_2011_Land_Cover_AK_20200724.zip “AK 2011 Land Cover”		389.73 MB	application/zip
NLCD_2011_Urban_Descriptor_AK_20200724.zip “AK 2011 Urban descriptor”		19.44 MB	application/zip

Related External Resources

Type: Online Link

Main page	https://doi.org/10.5066/P96HHBIE
Product page	http://www.mrlc.gov

Purpose

The goal of this project is to provide the Nation with complete, current and consistent public domain information on its land use and land cover.

National Land Cover Database (NLCD) 2011 - Alaska

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