National Land Cover Database Zone 01 Land Cover Layer

Metadata also available as

Frequently-anticipated questions:


What does this data set describe?

Title: National Land Cover Database Zone 01 Land Cover Layer
Abstract:
The National Land Cover Database 2001 land cover layer for mapping zone 01 was produced through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of federal agencies (www.mrlc.gov), consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (FWS), the Bureau of Land Management (BLM) and the USDA Natural Resources Conservation Service (NRCS). One of the primary goals of the project is to generate a current, consistent, seamless, and accurate National Land cover Database (NLCD) circa 2001 for the United States at medium spatial resolution. This landcover map and all documents pertaining to it are considered "provisional" until a formal accuracy assessment can be conducted. For a detailed definition and discussion on MRLC and the NLCD 2001 products, refer to Homer et al. (2004) and <http://www.mrlc.gov/mrlc2k.asp>. The NLCD 2001 is created by partitioning the U.S. into mapping zones. A total of 66 mapping zones were delineated within the conterminous U.S. based on ecoregion and geographical characteristics, edge matching features and the size requirement of Landsat mosaics. Mapping zone 01 encompasses whole or portions of several states, including the state of Washington. Questions about the NLCD mapping zone 01 can be directed to the NLCD 2001 land cover mapping team at the USGS/EROS, Sioux Falls, SD (605) 594-6151 or mrlc@usgs.gov.
Supplemental_Information:
Corner Coordinates (center of pixel, projection meters) Upper Left Corner: -2147160.00 meters(X), 3180540.00 meters(Y) Lower Right Corner: -1736280.00 meters(X), 2777100.00 meters(Y)
  1. How should this data set be cited?

    U.S. Geological Survey, 20030901, National Land Cover Database Zone 01 Land Cover Layer: None None, U.S. Geological Survey, Sioux Falls, SD.

    Online Links:

    Other_Citation_Details:
    References: Homer, C., C. Huang, L. Yang, B. Wylie and M. Coan, 2004. Development of a 2001 national land cover database for the United States. Photogrammetric Engineering and Remote Sensing Vol.70,No.7,pp 829-840 or online at www.mrlc.gov/publications. The USGS acknowledges the support of NOAA and Space Imaging in development of data in this zone.
    This is part of the following larger work.

    National Oceanographic and Atmospheric Administration (NOAA) Coastal Services Center (CSC)/Coastal Change Analysis Program (C-CAP), 20041001, C-CAP Washington 2000-Era Land Cover Metadata: NOAA Coastal Change Analysis Program (C-CAP), NOAA CSC, Charleston, SC.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -125.274529
    East_Bounding_Coordinate: -118.634037
    North_Bounding_Coordinate: 49.660920
    South_Bounding_Coordinate: 45.144016

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 18-Oct-1999
    Ending_Date: 22-Jul-2002
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: remote-sensing image

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 13449 x 13697 x 1, type Pixel

    2. What coordinate system is used to represent geographic features?

      The map projection used is Albers Conical Equal Area.

      Projection parameters:
      Standard_Parallel: 29.500000
      Standard_Parallel: 45.500000
      Longitude_of_Central_Meridian: -96.000000
      Latitude_of_Projection_Origin: 23.000000
      False_Easting: 0.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 30.000000
      Ordinates (y-coordinates) are specified to the nearest 30.000000
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    Layer_1
    NLDC Land Cover Layer (Source: National Land Cover Database 2001)

    ObjectID
    Internal feature number (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Count
    A nominal integer value that designates the number of pixels that have each value in the file; histogram column in ERDAS Imagine raster attributes table (Source: NLCD 2001)

    Integer

    Value
    Land Cover Class Code Value. Class definitions marked with an asterisk (*) are Coastal NLCD Classes only. (Source: NLCD 2001)

    ValueDefinition
    1No data value, Alaska zones only
    11Open Water - All areas of open water, generally with less than 25% cover or vegetation or soil
    12Perennial Ice/Snow - All areas characterized by a perennial cover of ice and/or snow, generally greater than 25% of total cover.
    21Developed, Open Space - Includes areas with a mixture of some constructed materials, but mostly vegetation in the form of lawn grasses. Impervious surfaces account for less than 20 percent of total cover. These areas most commonly include large-lot single-family housing units, parks, golf courses, and vegetation planted in developed settings for recreation, erosion control, or aesthetic purposes
    22Developed, Low Intensity -Includes areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 20-49 percent of total cover. These areas most commonly include single-family housing units.
    23Developed, Medium Intensity - Includes areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 50-79 percent of the total cover. These areas most commonly include single-family housing units.
    24Developed, High Intensity - Includes highly developed areas where people reside or work in high numbers. Examples include apartment complexes, row houses and commercial/industrial. Impervious surfaces account for 80 to100 percent of the total cover.
    31Barren Land (Rock/Sand/Clay) - Barren areas of bedrock, desert pavement, scarps, talus, slides, volcanic material, glacial debris, sand dunes, strip mines, gravel pits and other accumulations of earthen material. Generally, vegetation accounts for less than 15% of total cover.
    32Unconsolidated Shore* - Unconsolidated material such as silt, sand, or gravel that is subject to inundation and redistribution due to the action of water. Characterized by substrates lacking vegetation except for pioneering plants that become established during brief periods when growing conditions are favorable. Erosion and deposition by waves and currents produce a number of landforms representing this class.
    41Deciduous Forest - Areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. More than 75 percent of the tree species shed foliage simultaneously in response to seasonal change.
    42Evergreen Forest - Areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. More than 75 percent of the tree species maintain their leaves all year. Canopy is never without green foliage.
    43Mixed Forest - Areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. Neither deciduous nor evergreen species are greater than 75 percent of total tree cover.
    51Dwarf Scrub - Alaska only areas dominated by shrubs less than 20 centimeters tall with shrub canopy typically greater than 20% of total vegetation. This type is often co-associated with grasses, sedges, herbs, and non-vascular vegetation.
    52Shrub/Scrub - Areas dominated by shrubs; less than 5 meters tall with shrub canopy typically greater than 20% of total vegetation. This class includes true shrubs, young trees in an early successional stage or trees stunted from environmental conditions.
    71Grassland/Herbaceous - Areas dominated by grammanoid or herbaceous vegetation, generally greater than 80% of total vegetation. These areas are not subject to intensive management such as tilling, but can be utilized for grazing.
    72Sedge/Herbaceous - Alaska only areas dominated by sedges and forbs, generally greater than 80% of total vegetation. This type can occur with significant other grasses or other grass like plants, and includes sedge tundra, and sedge tussock tundra.
    73Lichens - Alaska only areas dominated by fruticose or foliose lichens generally greater than 80% of total vegetation.
    74Moss- Alaska only areas dominated by mosses, generally greater than 80% of total vegetation.
    81Pasture/Hay - Areas of grasses, legumes, or grass-legume mixtures planted for livestock grazing or the production of seed or hay crops, typically on a perennial cycle. Pasture/hay vegetation accounts for greater than 20 percent of total vegetation.
    82Cultivated Crops - Areas used for the production of annual crops, such as corn, soybeans, vegetables, tobacco, and cotton, and also perennial woody crops such as orchards and vineyards. Crop vegetation accounts for greater than 20 percent of total vegetation. This class also includes all land being actively tilled.
    90Woody Wetlands - Areas where forest or shrub land vegetation accounts for greater than 20 percent of vegetative cover and the soil or substrate is periodically saturated with or covered with water.
    91Palustrine Forested Wetland* -Includes all tidal and non-tidal wetlands dominated by woody vegetation greater than or equal to 5 meters in height and all such wetlands that occur in tidal areas in which salinity due to ocean-derived salts is below 0.5 percent. Total vegetation coverage is greater than 20 percent.
    92Palustrine Scrub/Shrub Wetland* - Includes all tidal and non-tidal wetlands dominated by woody vegetation less than 5 meters in height, and all such wetlands that occur in tidal areas in which salinity due to ocean-derived salts is below 0.5 percent. Total vegetation coverage is greater than 20 percent. The species present could be true shrubs, young trees and shrubs or trees that are small or stunted due to environmental conditions.
    93Estuarine Forested Wetland* - Includes all tidal wetlands dominated by woody vegetation greater than or equal to 5 meters in height, and all such wetlands that occur in tidal areas in which salinity due to ocean-derived salts is equal to or greater than 0.5 percent. Total vegetation coverage is greater than 20 percent.
    94Estuarine Scrub/Shrub Wetland* - Includes all tidal wetlands dominated by woody vegetation less than 5 meters in height, and all such wetlands that occur in tidal areas in which salinity due to ocean-derived salts is equal to or greater than 0.5 percent. Total vegetation coverage is greater than 20 percent.
    95Emergent Herbaceous Wetlands - Areas where perennial herbaceous vegetation accounts for greater than 80 percent of vegetative cover and the soil or substrate is periodically saturated with or covered with water.
    96Palustrine Emergent Wetland (Persistent)* - Includes all tidal and non-tidal wetlands dominated by persistent emergent vascular plants, emergent mosses or lichens, and all such wetlands that occur in tidal areas in which salinity due to ocean-derived salts is below 0.5 percent. Plants generally remain standing until the next growing season.
    97Estuarine Emergent Wetland* - Includes all tidal wetlands dominated by erect, rooted, herbaceous hydrophytes (excluding mosses and lichens) and all such wetlands that occur in tidal areas in which salinity due to ocean-derived salts is equal to or greater than 0.5 percent and that are present for most of the growing season in most years. Perennial plants usually dominate these wetlands.
    98Palustrine Aquatic Bed* - The Palustrine Aquatic Bed class includes tidal and nontidal wetlands and deepwater habitats in which salinity due to ocean-derived salts is below 0.5 percent and which are dominated by plants that grow and form a continuous cover principally on or at the surface of the water. These include algal mats, detached floating mats, and rooted vascular plant assemblages.
    99Estuarine Aquatic Bed* - Includes tidal wetlands and deepwater habitats in which salinity due to ocean-derived salts is equal to or greater than 0.5 percent and which are dominated by plants that grow and form a continuous cover principally on or at the surface of the water. These include algal mats, kelp beds, and rooted vascular plant assemblages.

    Red
    Red color code for RGB slice by value for canopy image display purposes. The value is arbitrarily assigned by the display software package, unless defined by user. Standard user defined ramp for NLCD project is start color light gray, end color red. (Source: NLCD 2001)

    Range of values
    Minimum:0
    Maximum:100
    Units:CSS Color Value Percentage
    Resolution:0.1

    Green
    Green color code for RGB slice by value for canopy image display purposes. The value is arbitrarily assigned by the display software package, unless defined by user. Standard user defined ramp for NLCD project is start color light gray, end color red. (Source: NLCD 2001)

    Range of values
    Minimum:0
    Maximum:100
    Units:CSS Color Value Percentage
    Resolution:0.1

    Blue
    Blue color code for RGB slice by value for canopy image display purposes. The value is arbitrarily assigned by the display software package, unless defined by user. Standard user defined ramp for NLCD project is start color light gray, end color red. (Source: NLCD 2001)

    Range of values
    Minimum:0
    Maximum:100
    Units:CSS Color Value Percentage
    Resolution:0.1

    Opacity
    A measure of how opaque, or solid, a color is displayed in a layer. (Source: NLCD 2001)

    Range of values
    Minimum:0
    Maximum:100
    Units:Percentage
    Resolution:0.1

    Entity_and_Attribute_Overview:
    Attributes defined by USGS and ESRI. Class Red Green Blue 0 0.000000000 0.000000000 0.000000000 1 0.000000000 1.000000000 0.000000000 11 0.325490196 0.462745098 0.662745098 12 0.854901961 0.913725490 1.000000000 21 0.913725490 0.819607843 0.815686275 22 0.890196078 0.615686275 0.545098039 23 0.976470588 0.000000000 0.000000000 24 0.705882353 0.000000000 0.000000000 31 0.741176471 0.725490196 0.670588235 32 1.000000000 1.000000000 1.000000000 41 0.443137255 0.701960784 0.419607843 42 0.137254902 0.423529412 0.231372549 43 0.752941176 0.827450980 0.607843137 51 0.694117647 0.588235294 0.235294118 52 0.835294118 0.764705882 0.533333333 71 0.925490196 0.925490196 0.796078431 72 0.823529412 0.823529412 0.505882353 73 0.635294118 0.796078431 0.321568627 74 0.513725490 0.725490196 0.619607843 81 0.901960784 0.882352941 0.282352941 82 0.709803922 0.486274510 0.200000000 90 0.760784314 0.878431373 0.949019608 95 0.486274510 0.674509804 0.772549020
    Entity_and_Attribute_Detail_Citation:
    Attribute accuracy is described, where present, with each attribute defined in the Entity and Attribute Section. Note: To ensure all areas of mapping zone 01 are completely covered, a 3,000 meter (100 Landsat pixels) buffer was added to the boundary of mapping zone 01.


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    U.S. Geological Survey, NOAA, Space Imaging

  3. To whom should users address questions about the data?

    U.S. Geological Survey
    Customer Services Representative
    USGS/EROS
    Sioux Falls, SD 57198-0001
    USA

    605/594-6151 (voice)
    605/594-6589 (FAX)
    custserv@usgs.gov

    Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
    Contact_Instructions:
    The USGS point of contact is for questions relating to the data display and download from this web site. For questions regarding data content and quality, refer to: <http://www.mrlc.gov/mrlc2k.asp> or email: mrlc@usgs.gov


Why was the data set created?

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.


How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 01-Oct-2002 - 20041001 (process 1 of 2)
    This dataset was created by Space Imaging. This version of the classification is the late-date (2000-era). The study area is the Coastal Washington Region. An early-date (1995-era) classification is also available for the same area.
    Summary- This section outlines the classification procedure for the Oregon C-CAP. The three dates of imagery were first reviewed for image quality and shifts between image dates. Training points were used as the dependent variable in a CART (Classification Analysis by Regression Tree) approach. Ancillary data layers were calculated from the TM data and were used as additional independent variables in the analysis. Different versions of the map were produced using different combinations of independent variables. The rough map represented the output from the CART classification routine. Ancillary data were used in spatial models were applied to the rough map to produce the provisional map. This represented a fully automated product. This product was then altered by hand edits to refine the classification. In addition, a percent impervious data layer developed from TM data using high resolution imagery, was imbedded into the classification to define the developed classes. This produced the final-with-edits version which is the final version of the classification and is the one described here.
    Pre-processing steps- Each Landsat TM scene was geo-referenced by USGS (United States Geological Survey) EROS. The Space Imaging staff reviewed the spectral and spatial quality of the imagery. Areas that were greater than 1-2 pixels off were sent back to USGS for reprocessing. The data was geo-referenced to Albers Conical Equal Area, with a spheroid of GRS 1980, and Datum of WGS84. The data units is in meters. The Washington TM data was delivered in the form of USGS zone mosaics. The data included three dates of TM: leaf-on, leaf-off, and spring. For each date of TM, spectral and tasseled cap data were received.
    Acquisition dates of Landsat ETM+ (TM) scenes used for land cover classification in zone 01 are as follows: SPRING- Index 1 for Path 45/Row 26 on 03/21/01 = Scene_ID 5045026000108010 Index 2 for Path 45/Row 27 on 03/26/00 = Scene_ID 7045027000008650 Index 1 for Path 45/Row 28 on 03/21/01 = Scene_ID 5045028000108010 Index 3 for Path 46/Row 26 on 05/07/01 = Scene_ID 7046026000112750 Index 4 for Path 46/Row 27 on 05/31/01 = Scene_ID 5046027000115110 Index 5 for Path 46/Row 28 on 04/10/00 = Scene_ID 5046028000010110 Index 6 for Path 47/Row 26 on 02/13/00 = Scene_ID 5047026000004410 Index 7 for Path 47/Row 27 on 02/26/02 = Scene_ID 7047027000205750 Index 7 for Path 47/Row 28 on 02/26/02 = Scene_ID 7047028000205750 Index 8 for Path 48/Row 26 on 04/03/01 = Scene_ID 7048026000109350 Index 8 for Path 48/Row 27 on 04/03/01 = Scene_ID 7048027000109350 LEAF ON (Summer)- Index 1 for Path 45/Row 26 on 07/16/00 = Scene_ID 7045026000019850 Index 2 for Path 45/Row 27 on 07/22/02 = Scene_ID 7045027000220350 Index 1 for Path 45/Row 28 on 07/16/00 = Scene_ID 7045028000019850 Index 3 for Path 46/Row 26 on 08/11/01 = Scene_ID 7046026000122350 Index 4 for Path 46/Row 27 on 07/07/00 = Scene_ID 7046027000018950 Index 4 for Path 46/Row 28 on 07/07/00 = Scene_ID 7046028000018950 Index 5 for Path 47/Row 26 on 07/30/00 = Scene_ID 7047026000021250 Index 5 for Path 47/Row 27 on 07/30/00 = Scene_ID 7047027000021250 Index 6 for Path 47/Row 28 on 07/01/01 = Scene_ID 7047028000118250 Index 7 for Path 48/Row 26 on 07/21/00 = Scene_ID 7048026000020350 Index 8 for Path 48/Row 27 on 06/03/00 = Scene_ID 7048027000015550 LEAF-OFF (Fall)- Index 1 for Path 45/Row 26 on 10/18/99 = Scene_ID 7045026009929150 Index 2 for Path 45/Row 27 on 10/04/00 = Scene_ID 7045027000027850 Index 3 for Path 45/Row 28 on 08/17/00 = Scene_ID 7045028000023050 Index 4 for Path 46/Row 26 on 09/12/01 = Scene_ID 7046026000125550 Index 5 for Path 46/Row 27 on 09/25/00 = Scene_ID 7046027000026950 Index 5 for Path 46/Row 28 on 09/25/00 = Scene_ID 7046028000026950 Index 6 for Path 47/Row 26 on 10/05/01 = Scene_ID 7047026000127850 Index 7 for Path 47/Row 27 on 11/01/99 = Scene_ID 7047027009930550 Index 8 for Path 47/Row 28 on 10/16/99 = Scene_ID 7047028009928950 Index 9 for Path 48/Row 26 on 09/23/00 = Scene_ID 7048026000026750 Index 9 for Path 48/Row 27 on 09/23/00 = Scene_ID 7048027000026750
    Field-Collected Data- The goals of the field data collection were to sample the diversity of the landscape, within the classes, and among image dates. Classes that would be more difficult to collect from air photos were targeted for field data collection. To meet these goals, Space Imaging stratified the image into spectral clusters and located the field sites throughout the study area based on these. In addition to these pre-arranged sites, Space Imaging collected points while driving between locations. Due to limited time and accessibility, not all polygons were assessed in the field. Those that we did not visit on the ground were labeled with digital orthophotographs or Emerge data if it was available. Both training and validation points were collected together. See the accuracy assessment section to see how the points were split into training and validation points.
    Space Imaging used laptop computers and GPS (Global Positioning System)to correctly locate field points on the TM imagery. Software downloaded from the Minnesota's Department of Natural Resources (DNR)was used to connect the Garmin GPS to the laptop (<http://www.dnr.state.mn.us/mis/gis/tools/arcview/extensions/DNRGarmin/DNRGarmin.html>) computer and ESRI's ArcView software. Space Imaging's programmer developed an ArcView application that allowed entry of location and field notes with a click of the mouse. These data were stored in a shape file.
    The items that were collected were- Land Cover characterization Special conditions and remarks Photograph Number Date/time X,Y location
    The data and equipment used for the fieldwork are as follows- Ancillary datasets- TIGER 2000 NLCD NWI - mosaicked into zones State road map and Delorme state atlas www.delorme.com
    Hardware- Lap-tops with ArcView and data GARMIN GPS modules and external antennae, redundant data cables Cameras Backup devices (Floppy Drives) Extra batteries (lap-top and GPS) Mobile phones System backup CD's with data and software Compass Binoculars Field notebooks with instructions and road maps with pre-determined routes Wetland and Vegetation Field Guides
    Imagery- Multi-spectral data for each zone Initial classifications
    Classification- After the field points for training were collected, they were combined with photo-interpreted points and used as the dependent variable in a CART classification approach. Many layers tested as independent layers. They included three dates of spectral and tasseled cap imagery, DEM, slope, aspect, texture, band indices (NDVI, Moisture, NDVI-Green), shape indices fractal dimension, compactness, convexity, and form), Census data (housing and population density). Statistical analyses and visual inspection of the output was used to eliminate data that was redundant or not useful in the classification. Additional training points were added to help reduce some of the confusion between classes. The rough classification was created at the end of this process using only the CART discrete decision-tree software. A provisional classification was produced by applying spatial models using ancillary data to the rough classification. The provisional map was then edited using hand editing techniques while using high resolution imagery as reference data. Independently, of this process, Space Imaging produced percent impervious data layers for Washington. This layer was developed from Regression Tree and used impervious classifications from IKONOS imagery to predict pixel level percent impervious at the TM pixel level. The continuous percent impervious data was thresholded to produce the developed categories and imbedded into the final map.
    Attributes for this product are as follows- 0 Background 1 Unclassified (Cloud, Shadow, etc) 2 High Intensity Developed 3 Low Intensity Developed 4 Cultivated Land 5 Grassland 6 Deciduous Forest 7 Evergreen Forest 8 Mixed Forest 9 Scrub/Shrub 10 Palustrine Forested Wetland 11 Palustrine Scrub/Shrub Wetland 12 Palustrine Emergent Wetland 13 Estuarine Forested Wetland 14 Estuarine Scrub/Shrub Wetland 15 Estuarine Emergent Wetland 16 Unconsolidated Shore 17 Bare Land 18 Water 19 Palustrine Aquatic Bed 20 Estuarine Aquatic Bed 21 Tundra 22 Snow/Ice
    Ancillary Datasets- Non-TM image datasets used are DEM (Digital Elevation Model), slope, aspect, positional index, NWI, NLCD, TIGER2000, field-collected points, photo-interpreted points, Washington (Gap Analysis Program), Census data (housing and population density), Ecoregions, IVMP (Interagency Vegetation Mapping Program), Washington Coastal Atlas, Washington ShoreZone Inventory Data.
    QA/QC Process- There were several QA/QC steps involved in the creation of this product. First, there was an internal QA/QC. This was done by viewing the classification frame- by-frame along with the TM imagery, the classification, and high resolution reference imagery. NOAA staff completed a similar review and provided both general and point comments.
    Post-Processing Steps- Both Washington and Oregon zones were classified concurrently but independently. When they were completed, they were edgematched to each other.

    Person who carried out this activity:

    CRS (Coastal Remote Sensing) Program Manager
    NOAA Coastal Services Center Coastal Change Analysis Program (C-CAP)
    CRS Program Manager
    2234 S. Hobson Ave.
    Charleston, SC 29405
    USA

    843-740-1210 (voice)
    843-740-1224 (FAX)
    clearinghouse@csc.noaa.gov

    Hours_of_Service: 8:00 am to 5:00 p.m. EST. M-F
    Data sources produced in this process:
    • NOAA CSC

    Date: Unknown (process 2 of 2)
    Methods used to generate the land cover dataset for zone 01 described above are similar to and compatible with methods used in other zones of the NLCD dataset. For coastal zones mapped by NOAA and/or NOAA contractors, the land cover dataset classification codes and the source dataset for classification of urban areas is different. For national consistency, an additional process step was added to cross-walk the NOAA class codes to standard NLCD 2001 class codes described in the Entity and Attribute Information section of this document. NOAA urban pixel values were replaced with values determined from the NLCD 2001 percent imperviousness mapping product. The four classes in urban and suburban areas were determined from the percent imperviousness mapping product (described in the next section). The threshold for the four classes is: (1) developed open space (imperviousness < 20%), (2) low-intensity developed (imperviousness from 20 - 49%), (3) medium intensity developed (imperviousness from 50 -79%), and (4) high-intensity developed (imperviousness > 79%).
    The completed single pixel product was then generalized to a 1 acre (approximately 5 ETM+ 30 m pixel patch) minimum mapping unit product using a "smart eliminate" algorithm. This aggregation program subsumes pixels from the single pixel level to a 5- pixel patch using a queens algorithm at doubling intervals. The algorithm consults a weighting matrix to guide merging of cover types by similarity, resulting in a product that preserves land cover logic as much as possible.

    Person who carried out this activity:

    U.S. Geological Survey
    Customer Services Representative
    USGS/EROS
    Sioux Falls, SD 57198-0001
    USA

    605/594-6151 (voice)
    605/594-6589 (FAX)
    custserv@usgs.gov

    Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
    Data sources used in this process:
    • Landsat ETM, DOQQ, USDA, FIA, DEM, USGS/EROS, IKONOS

    Data sources produced in this process:

    • USGS NLCD

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    According to accuracy assessment performed by Space Imaging, the overall accuracy is 86.1% and 85.0% Kappa. The accuracy results shown below are from a combined accuracy completed on both Oregon and Washington C-CAP areas. A total of 1043 points are located in Washington and 1165 points are located in Oregon.
    Each class accuracy is as follows: (Errors of Omission/Commission) 0 Background (N/A) 1 Unclassified (Cloud, Shadow, etc)(N/A) 2 High Intensity Developed (88%/98%) 3 Low Intensity Developed (99%/89%) 4 Cultivated Land (81%/79%) 5 Grassland (86%/81%) 6 Deciduous Forest (76%/81%) 7 Evergreen Forest (95%/90%) 8 Mixed Forest (80%/76%) 9 Scrub/Shrub (74%/88%) 10 Palustrine Forested Wetland (77%/78%) 11 Palustrine Scrub/Shrub Wetland (67%/70%) 12 Palustrine Emergent Wetland (83%/79%) 13 Estuarine Forested Wetland (N/A) 14 Estuarine Scrub/Shrub Wetland (N/A) 15 Estuarine Emergent Wetland (79%/79%) 16 Unconsolidated Shore (94%/96%) 17 Bare Land (88%/91%) 18 Water (98%/99%) 19 Palustrine Aquatic Bed (N/A) 20 Estuarine Aquatic Bed (100%/96%) 21 Tundra (N/A) 22 Snow/Ice (96%/100%)
    The validation points were both collected in the field and photo interpreted. The accuracy assessment selection methods were developed to minimize spatial autocorrelation between the training and accuracy assessment. The first pool of accuracy assessment sites came from field data and photo interpretation of black and white digital orthophotos and digital color infrared imagery (primarily Emerge and Ikonos data). These sites were collected prior to initial mapping and were collected at the same time as the training data. The sites were selected to capture the physical and spectral diversity of the land cover. After these sites were identified, they were separated into training and accuracy assessment sites by imposing a 1 km x 1 km grid over the study area. Accuracy assessment sites could only be selected from alternate 1 km squares. Only 1 sample per class was allowed from each potential square. After the first criteria was met, the accuracy assessment sites were buffered to see if they fell within 1000 meters of another accuracy assessment site of the same class or within 1000 meters of a training site of the same class. Those that fell within the 1000 meter buffer were eliminated. All sites were to be from a homogeneous 3x3 area.
    After an analysis of the point distribution, it became clear that there were not enough samples for every class. The remaining points were selected from the initial draft final classification and had to be a homogeneous 3x3 area. A stratified random sample was used to locate sites. These sites were restricted to the same alternate 1 km x 1 km grid that was used to separate training from AA sites in the initial analysis. Sampling was limited to areas where there was high resolution color infrared imagery. The imagery included the previous Ikonos and Emerge imagery, but also included an additional 60 scenes of Ikonos imagery. The additional Ikonos imagery provided sampling areas across the entire study area. When possible, we tried to identify 50 samples of the uncommon classes and 20 sites of the common classes. Samples were selected for the common classes so that there were samples for classes using this methodology.
    In total, an additional 637 additional points to the accuracy assessment analysis for a total of 2208. All classes have a minimum of 50 accuracy assessment points except for estuarine aquatic bed and estuarine emergent. These classes have 24 and 29 sites respectively. These classes are limited in the study area and to some extent in the imagery that was available to sample from.
    Also as part of the assessment, NOAA staff field tested the classification to determine a subjective goodness of fit.
    Post-Processing Steps: None
    Known Problems: None
    Spatial Filters: None

  2. How accurate are the geographic locations?

    N/A

  3. How accurate are the heights or depths?

    N/A

  4. Where are the gaps in the data? What is missing?

    This NLCD product of mapping zone 01 Land Cover layer is the version dated November 8, 2006.

  5. How consistent are the relationships among the observations, including topology?

    The NLCD 2001 database for mapping zone 01 consists of three main data products including: (1) per pixel classified land-cover data (2) sub-pixel percent imperviousness and (3) sub-pixel percent tree canopy density. The land-cover database also includes three additional metadata layers that provide users a spatial node map of the land cover classification. The three layers are: (a) a spatial node map of the land cover classification, (b) a spatial confidence map of the land cover classification, and, (c) a text file of logical statements related to the land cover classification.
    Conceptually, the descriptive tree is a classification tree generated by using the final minimum-map- unit land cover product (1 acre) as training data, and Landsat and other ancillary data as predictors. The goal of the descriptive tree is to summarize the effects of boosted trees (10 sequential classification trees) into a single condensed decision tree that can be used as a diagnostic tool for the classification process. This descriptive tree can be used to assess the relative importance of each of the input data sets on each land cover class. Such information may also be useful to customize the minimum-mapping-unit classification to meet a user's specific needs through raster modeling. Descriptive trees usually capture 60 to 80% of the information from the original land cover data.
    The leaf or terminal nodes of the descriptive tree are assigned to sequential numbers (called node numbers) and mapped across the entire mapping zone on a pixel-by-pixel basis. These node numbers can then be matched with the various conditional statements associated with each respective terminal node. This spatial layer appears similar to a cluster map, but is the result of a supervised classification - not an unsupervised clustering. This node map can potentially be used as input by users to customize NLCD land cover, by linking the spatial extent of an individual node with the rules of the conditional statement.
    The Land Cover spatial classification confidence data layer is provided to users to help determine the per-pixel spatial confidence of the NLCD 2001 land cover prediction from the descriptive tree. The C5 algorithm produces an estimate (a value between 0% and 100%) that indicates the confidence of rule predictions at each node based on the training data. This spatial confidence map should be considered as only one indicator of relative reliability of the land cover classification, rather than a precise estimate. Users should be aware that this estimate is made based on only training data, and is derived from a generalized descriptive decision tree that reproduces the final land cover data. However, this layer provides valuable insight for a user to determine the risk or confidence they choose to place in each pixel of land cover.
    A logic statement from a descriptive tree classification describes each classification rule for each classified pixel. An example of the logic statement follows:
    IF tasseled-cap wetness > 140 and imperviousness = 0 and canopy density < 4, then classify as Water
    This logic file can be used in combination with the spatial node map to identify classification logic and allow modifications of the classification based on user's knowledge and/or additional data sets.
    Additional information may be found at <http://www.mrlc.gov/mrlc2k_nlcd.asp>.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints: None

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey
    Customer Service Representative
    USGS/EROS
    Sioux Falls, SD 57198-0001
    USA

    605/594-6151 (voice)
    605/594-6589 (FAX)
    custserv@usgs.gov

    Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
    Contact_Instructions:
    The USGS point of contact is for questions relating to the data display and download from this web site. Questions about the NLCD mapping zone 01 can be directed to the NLCD 2001 land cover mapping team at the USGS/EROS, Sioux Falls, SD (605) 594-6151 or mrlc@usgs.gov.
  2. What's the catalog number I need to order this data set?

    Downloadable data

  3. What legal disclaimers am I supposed to read?

    Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made by the USGS regarding the use of the data on any other system, nor does the act of distribution constitute any such warranty. Data may have been compiled from various outside sources. Spatial information may not meet National Map Accuracy Standards. This information may be updated without notification. The USGS shall not be liable for any activity involving these data, installation, fitness of the data for a particular purpose, its use, or analyses results.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Contact Customer Services Representative

  6. What hardware or software do I need in order to use the data set?

    ESRI ArcMap Suite and/or Arc/Info software, and supporting operating systems.


Who wrote the metadata?

Dates:
Last modified: 16-Nov-2006
Metadata author:
U.S. Geological Survey
Customer Services Representative
USGS/EROS
Sioux Falls, SD 57198-0001
USA

605/594-6151 (voice)
605/594-6589 (FAX)
custserv@usgs.gov

Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.6 on Wed Apr 10 12:34:26 2013