U.S. Geological Survey Gap Analysis Program- Land Cover Data v2.2

This page last updated: 06/11/2013
Metadata created using FGDC Content Standard for Digital Geospatial Metadata


Go to Section:
1. Overview
2. Data Quality
3. Data Organization
4. Coordinate System
5. Attributes
6. Distribution - Get Data
7. Metadata Reference

Section 1 Overview
Originator U.S. Geological Survey Gap Analysis Program, Anne Davidson, Spatial Ecologist
Title U.S. Geological Survey Gap Analysis Program- Land Cover Data v2.2
Abstract This dataset combines the work of several different projects to create a seamless data set for the contiguous United States. Data from four regional Gap Analysis Projects and the LANDFIRE project were combined to make this dataset. In the northwestern United States (Idaho, Oregon, Montana, Washington and Wyoming) data in this map came from the Northwest Gap Analysis Project. In the southwestern United States (Colorado, Arizona, Nevada, New Mexico, and Utah) data used in this map came from the Southwest Gap Analysis Project. The data for Alabama, Florida, Georgia, Kentucky, North Carolina, South Carolina, Mississippi, Tennessee, and Virginia came from the Southeast Gap Analysis Project and the California data was generated by the updated California Gap land cover project. The Hawaii Gap Analysis project provided the data for Hawaii. In areas of the county (central U.S., Northeast, Alaska) that have not yet been covered by a regional Gap Analysis Project, data from the Landfire project was used. Similarities in the methods used by these projects made possible the combining of the data they derived into one seamless coverage. They all used multi-season satellite imagery (Landsat ETM+) from 1999-2001 in conjunction with digital elevation model (DEM) derived datasets (e.g. elevation, landform) to model natural and semi-natural vegetation. Vegetation classes were drawn from NatureServe's Ecological System Classification (Comer et al. 2003) or classes developed by the Hawaii Gap project. Additionally, all of the projects included land use classes that were employed to describe areas where natural vegetation has been altered. In many areas of the country these classes were derived from the National Land Cover Dataset (NLCD). For the majority of classes and, in most areas of the country, a decision tree classifier was used to discriminate ecological system types. In some areas of the country, more manual techniques were used to discriminate small patch systems and systems not distinguishable through topography. The data contains multiple levels of thematic detail. At the most detailed level natural vegetation is represented by NatureServe's Ecological System classification (or in Hawaii the Hawaii GAP classification). These most detailed classifications have been crosswalked to the five highest levels of the National Vegetation Classification (NVC), Class, Subclass, Formation, Division and Macrogroup. This crosswalk allows users to display and analyze the data at different levels of thematic resolution. Developed areas, or areas dominated by introduced species, timber harvest, or water are represented by other classes, collectively refered to as land use classes; these land use classes occur at each of the thematic levels. Raster data in both ArcGIS Grid and ERDAS Imagine format is available for download at http://gis1.usgs.gov/csas/gap/viewer/land_cover/Map.aspxSix
Purpose U.S. Geological Survey Gap Analysis Program Land Cover Data covers the continental United States, Alaska and Hawaii.
The original national coverage has been clipped to each of the 50 states, the 21 Landscape Conservation Cooperatives and 6 regions, This data may represent one of these subsets.
Time Period of Content Date
Currentness Reference ground condition
Progress In work
Maintenance and Update Frequency Irregular
Spatial Extent of Data
Bounding Coordinates -128.446443
-64.761475
52.496415
22.670194
Place Keywords Continental United States
Theme Keywords land cover
Theme Keyword Thesaurus None
Access Constraints none
Use Constraints The digital land cover dataset may be used for various purposes with user's discretion. Specifically, this dataset was created for regional terrestrial biodiversity assessment. These data are not intended to be used at scales larger than 1:100,000.
Contact Person Information , Spatial Ecologist

530 S. Asbury Suite 1
Moscow, Idaho  99163
Phone: 208-885-3720
Email: adavidson@uidaho.edu
Browse Graphic None available
Associated Data Sets

Section 2 Data Quality
Attribute Accuracy Accuracy assessments have been conducted for part of the Northwestern United States and the Southwestern United States
Logical Consistency Not applicable for raster data
Completeness All cells within the continental United States heve been assigned an Ecological System or land use Value and description. Work is ongoing to improve country wide consistancy in the class assignment process.
Horizontal Positional Accuracy
Lineage

Section 3 Spatial Data Organization (not used in this metadata)

Section 4 Coordinate System
Horizontal Coordinate Scheme
Horizontal Datum D North American 1983
Horizontal Units
Cell Width 0.0000000037527980722984474
Cell Height 0.0000000037527980722984474

Section 5 Attributes
Overview
Detailed Citation
Table Detail:
natgaplandcov_v2_2.img.vat
Field NameValid ValuesDefinitionDefinition Source
OID
-
Internal feature number.ESRI
VALUE
-
Code used to identify Ecological System or land use class. Repeated for Alaska, Hawaii, and Continental U.S. datasetsGAP
COUNT
-
Number of 30 m x 30 m pixels per classGAP
RED
-
Red color value
GREEN
-
Green color value
BLUE
-
Blue color value
CL
-
Code Representing the National Vegetation Classification- Classsee http://usnvc.org/overview/ for more details on NVC
NVC_CLASS
-
Textual description of the National Vegetation Classification-Class or Land Use Classsee http://usnvc.org/overview/ for more details on NVC
SC
-
Code Representing the National Vegetation Classification- Subclassssee http://usnvc.org/overview/ for more details on NVC
NVC_SUBCL
-
Textual description of the National Vegetation Classification-Subclass or Land Use Classsee http://usnvc.org/overview/ for more details on NVC
FRM
-
Code Representing the National Vegetation Classification- Formationsee http://usnvc.org/overview/ for more details on NVC
NVC_FORM
-
Textual description of the National Vegetation Classification- Formation or Land Use Classsee http://usnvc.org/overview/ for more details on NVC
DIV
-
Code Representing the National Vegetation Classification- Divisionsee http://usnvc.org/overview/ for more details on NVC
NVC_DIV
-
Textual description of the National Vegetation Classification-Division or Land Use Classsee http://usnvc.org/overview/ for more details on NVC
MACRO_CD
-
Code Representing the National Vegetation Classification- Macrogroupsee http://usnvc.org/overview/ for more details on NVC
NVC_MACRO
-
Textual description of the National Vegetation Classification- Macrogroup or Land Use Classsee http://usnvc.org/overview/ for more details on NVC
LEVEL3
-
Code used to identify the Ecological System/ Land use. Highest level of thematic resolution in data. Was used as the grid value in Version 1 of the National Gap Land Cover Data
ECOLSYS_LU
-
Textual description of the Ecological System or Land Use Classsee http://www.natureserve.org/explorer/ and http://www.natureserve.org/publications/usEcologicalsystems.jsp for details
NVCMES
-
code combining all NVC codes and Ecological systems codes into one valueGAP


Section 6 Distribution
Publisher
Publication Date
Contact Person Information , Spatial Ecologist


,  
Phone: 208 885-3720
Email:
Distributor's Data Set Identifier
Distribution Liability See access and use constraints information.
Ordering Instructions
Online Linkage None available

Section 7 Metadata Reference
Metadata Date 06/11/2013
Contact Person Information , Spatial Ecologist

530 S. Asbury Suite 1
Moscow, Idaho  83843
Phone: 208 885-3720
Email: adavidson@uidaho.edu
Metadata Standard Name FGDC Content Standard for Digital Geospatial Metadata
Metadata Standard Version FGDC-STD-001-1998
Metadata Standard Online Linkage


This page last updated: 06/11/2013
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