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100-Meter Resolution Tree Canopy of Alaska, 2001

Identification Information

Citation
Title
100-Meter Resolution Tree Canopy of Alaska, 2001
Originator
Geological Survey (U.S.)
Publisher
Geological Survey (U.S.)
Place of Publication
Rolla , MO , US
Publication Date
2013-01-01
Identifier
http://purl.stanford.edu/cv542qn8153
Geospatial Data Presentation Form
mapDigital
Collection Title
National Atlas of the United States of America, 1997-2014
Other Citation Details
These data were downloaded from the National Atlas website (http://www.nationalatlas.gov/atlasftp.html) in August 2014.
Abstract
This raster layer is a georeferenced image containing tree canopy data for Alaska, in an Albers Equal-Area Conic projection and at a resolution of 100 meters. The tree canopy data were derived from the 2001 National Land Cover Database (NLCD) Percent Tree Canopy data set, a product of the Multi-Resolution Land Characteristics Consortium (MRLC). The MRLC is a multi-agency cooperative effort to study land cover change. This layer is part of the 1997-2014 edition of the National Atlas of the United States.
Purpose
The 100-meter resolution tree canopy data were developed to portray the tree canopy of the United States at 1:1,000,000 scale. They are intended primarily for visual purposes. The original NLCD data should be used for conducting scientific analysis.
Supplemental Information
NLCD data sets at 30-meter resolution may be downloaded from the MRLC Web site, http://www.mrlc.gov/nlcd01_data.php. Further information on NLCD, related data sets, and land cover research may be found at the online USGS Land Cover Institute http://landcover.usgs.gov/. Pixel values for tree canopy data and their corresponding RGB colors are listed in the color ramp (.clr) file that accompanies the data set. This table shows all tree canopy classes and the RGB color values used to represent them. Pixel value NLCD 2001 Tree Canopy classes R G B ================================================================================== 1 through 100 Percent tree canopy, 1% through 100% See .clr for RGB's 101, 102, 103 Non-U.S. land 240 235 211 104 Background U.S. land 104 104 104 0 Ocean water 193 224 250 Pixel values 1 through 100 represent the percentage covered by tree canopy, as seen from above. Pixel value 101 represents land in Canada or the British Virgin Islands. Pixel value 102 represents land in Mexico or Russia. Pixel value 103 represents land in The Bahamas and Cuba in the southeastern part of the data set. Pixel value 104 represents U.S. land that does not have valid data values. There are no null values in the image. Included with the GeoTIFF are an auxiliary information file (.aux.xml), an image overview file (.ovr), a value attribute database file (.vat.dbf), a .tfw file (more information included below), a .prj file (more information included below), and an Adobe Color Table (.act) file. The contents of the associated world file (.tfw) are: 100.0 0.0 0.0 -100.0 -3326950.0 2437950.0 The projection (.prj) file contains the following information: PROJCS["Albers_NAD83_Alaska", GEOGCS["GCS_North_American_1983", DATUM["D_North_American_1983", SPHEROID["GRS_1980",6378137.0,298.257222101]], PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433]], PROJECTION["Albers"], PARAMETER["False_Easting",0.0], PARAMETER["False_Northing",0.0], PARAMETER["Central_Meridian",-154.0], PARAMETER["Standard_Parallel_1",55.0], PARAMETER["Standard_Parallel_2",65.0], PARAMETER["Latitude_Of_Origin",50.0], UNIT["Meter",1.0]] Data set extent in meters (Albers Equal-Area Conic projection) North 2438000 West -3327000 East 1654000 South 346000 There are no NULL or NODATA values in the GeoTIFF. Instead, all tree canopy values in oceans have been set to zero as part of the masking process. A copy of the land/water mask used in processing is available on request. Information about National Atlas Web services can be found on the Web Map and Web Feature Services page; see http://nationalatlas.gov/infodocs/webservices.html. ; {"gdaId" : 6152790}
Scale Denominator
1000000
Temporal Extent
Currentness Reference
ground condition
Time Instant
2001-01-01T00:00:00
Bounding Box
West
-180
East
180
North
71.954724
South
43.053445
ISO Topic Category
imageryBaseMapsEarthCover
biota
Place Keyword
Alaska
Place Keyword Thesaurus
geonames
Theme Keyword
Forest canopies
Forests and forestry
Theme Keyword Thesaurus
lcsh
Legal Constraints
Use Limitation
Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. No responsibility is assumed by the U.S. Geological Survey in the use of these data.
Status
completed
Maintenance and Update Frequency
notPlanned
Collection
Collection Title
National Atlas of the United States of America, 1997-2014
URL
http://purl.stanford.edu/cv275yx9215
Language
eng
Credit
U.S. Geological Survey. (2013). 100-Meter Resolution Tree Canopy of Alaska, 2001. USGS. Available at: http://purl.stanford.edu/cv542qn8153.
Point of Contact
Contact
John Hutchinson
Delivery Point
47914 252nd Street
City
Sioux Falls
Administrative Area
South Dakota
Postal Code
57198-0001
Country
US
Email
atlasmail@usgs.gov
Phone
1 605 594 6049

Spatial Reference Information

Reference System Identifier
Code
0
Code Space
Version

Data Quality Information

Lineage
Process Step
Description
Four tree canopy mosaics at 30-meter resolution were downloaded from the MRLC web site and used to produce tree canopy data files of the conterminous United States, Alaska, Hawaii, and Puerto Rico and the U.S. Virgin Islands. NLCD stores data for the conterminous United States, Alaska, and Hawaii in the same Albers Equal-Area Conic projection used by the National Atlas. Data for Puerto Rico and the U.S. Virgin Islands (PRVI) were reprojected to match the Albers projection parameters used by the National Atlas for that area. All data were resampled to 100-meter resolution and extents set to match National Atlas neatlines for the four areas. This map layer includes the data file for Alaska. Using the ArcGIS Feature-to-Raster command, a 0/1 land/water mask for Alaska was created from the 1:1,000,000-scale National Atlas coastline, at the same 100-meter resolution and with the same extent as the tree canopy data. The land/water mask was applied to the tree canopy grid with a software routine that used the ArcGIS Multiply command to clip tree canopy values that fell in ocean areas. Tree canopy values were not filled out to the coastline. Ocean areas were set to a pixel value of 0. The land/water mask is available on request. In the conterminous United States tree canopy data set, non-data pixels were set to separate values: 101 for Canada, 102 for Mexico, and 103 for The Bahamas and Cuba. In Alaska: 101 for Canada and 102 for Russia. In PRVI: 101 for the British Virgin Islands.
Process Date
2012-01-01T00:00:00
Source
Title
1:1,000,000-Scale Coastlines of the United States
Publication Date
2012-07-01
Originator
National Atlas of the United States
Description
Spatial information.
Source
Title
NLCD 2001 Percent Tree Canopy
Publication Date
2007-01-01
Originator
U.S. Geological Survey
Publisher
U.S. Geological Survey
Description
Spatial and attribute information

Distribution Information

Format Name
GeoTIFF
Distributor
Stanford Geospatial Center
Online Access
http://purl.stanford.edu/cv542qn8153
Protocol
http
Name
treeaki0100a.tif
Function
download

Content Information

Content Type
thematicClassification

Spatial Representation Information

Raster
Number of Dimensions
2
Row Count
20920
Column Count
49810
Cell Geometry Type
area
Corner Points
Point
-3327000.000000 346000.000000
Point
-3327000.000000 2438000.000000
Point
1654000.000000 2438000.000000
Point
1654000.000000 346000.000000
Center Point
-836500.000000 1392000.000000

Metadata Reference Information

Hierarchy Level
dataset
Metadata File Identifier
edu.stanford.purl:cv542qn8153
Parent Identifier
http://purl.stanford.edu/cv275yx9215.mods
Dataset URI
http://purl.stanford.edu/cv542qn8153
Metadata Date Stamp
2016-01-12
Metadata Standard Name
ISO 19139 Geographic Information - Metadata - Implementation Specification
Metadata Standard Version
2007
Character Set
utf8
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