National Land Cover Database Zone 01 Tree Canopy Layer

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Frequently-anticipated questions:


What does this data set describe?

Title: National Land Cover Database Zone 01 Tree Canopy Layer
Abstract:
The National Land Cover Database 2001 tree canopy 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. For a detailed definition and discussion on MRLC and the NLCD 2001 products, refer to Homer et al. (2003) and <http://www.mrlc.gov/mrlc2k.asp.The> NLCD 2001 was 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 the western portion of Washington state . Questions about the NLCD mapping zone 01 can be directed to the NLCD 2001 land cover mapping team at the National Center, EROS, Sioux Falls, SD (605) 594-6151 or mrlc@usgs.gov.
Supplemental_Information:
Corner Coordinates (center of pixel, projection meters)Upper Left Corner: -2154300 meters(X), 3183760 meters(Y)Lower Right Corner: -1730730 meters(X), 2774050 meters(Y)Spatial-specific information not available
  1. How should this data set be cited?

    U.S. Geological Survey, 20030901, National Land Cover Database Zone 01 Tree Canopy 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.Huang, C., L. Yang, B. Wylie, and C. Homer, 2001. A strategy for estimating tree canopy density using Landsat 7 ETM+ and high resolution images over large areas. In: Third International Conference on Geospatial Information in Agriculture and Forestry; November 5-7, 2001; Denver, Colorado. CD-ROM, 1 disk.The USGS acknowledges the support of Space Imaging in development of data in this zone.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.72848576
    East_Bounding_Coordinate: -120.80586473
    North_Bounding_Coordinate: 48.18075242
    South_Bounding_Coordinate: 46.94310188

  3. What does it look like?

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

    Beginning_Date: 16-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 13658 x 14120 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 Canopy Layer (Source: National Land Cover Database 2001)

    ObjectID
    Internal feature number (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Value
    Percent Canopy (Source: NLCD 2001)

    Range of values
    Minimum:0
    Maximum:1
    Units:percentage
    Resolution:0.1

    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

    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.
    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 Coastal Analysis Program, Space Imaging.

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

    U.S. Geological Survey
    Customer Services Representative
    National Center, 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: Unknown (process 1 of 2)
    The method employed to map tree canopy density for NLCD 2001 consists of three key steps: deriving reference data of tree canopy density from the high spatial resolution images, calibrating density prediction models using reference data and Landsat spectral bands, and extrapolating the developed models spatially to map per-pixel tree canopy density. This method is described in detail in Huang et al. (2001). This approach was applied to mapping zone 01 by Space Imaging.

    Person who carried out this activity:

    Space Imaging - Sanborn Map Company
    c/o Maria Fiorella
    421 South West 6th Avenue, #850
    Portland, OR 97204
    USA

    503/228-8708 (voice)
    503/228-8751 (FAX)
    mfiorella@sanborn.com

    Data sources used in this process:
    • Landsat ETM, DOQQ, National Center, EROS

    Data sources produced in this process:

    • USGS NLCD

    Date: Unknown (process 2 of 2)
    To develop adequate training data for tree canopy density estimation, 19 1-m resolution DOQQs across mapping zone 01 were classified into either tree canopy or non-tree canopy areas, and then values summed within each 30 meter Landsat pixel cell to obtain the percentage of tree canopy. The training data were selected based on the degree of variance each training data set possesses with regards to Landsat ETM+ imagery used for mapping. Each added training data set decreased the amount of variance present within the Landsat data as a whole. The process was repeated until the required number of samples 70,192 had been allocated.By combining the training data with Landsat spectral data and other ancillary data, tree canopy prediction models were developed using "Cubist". After the best combination of possible input data layers had been determined and the final percent canopy density layer produced, a mask was made from the final land cover classification of the mapping zone and was used to eliminate those pixels from the canopy density file that fall into non-forested areas. The mask includes 5 land cover classes (deciduous forest, coniferous forest, mixed forest, woody wetlands, and developed open space).Acquisition dates of Landsat ETM+ (TM) scenes used for land cover classification in this zone are as follows:SPRING-Index 1 for Path 45/Row 26 on 03/21/01 = Scene_ID 5045026000108010Index 2 for Path 45/Row 27 on 03/26/00 = Scene_ID 7045027000008650Index 1 for Path 45/Row 28 on 03/21/01 = Scene_ID 5045028000108010Index 3 for Path 46/Row 26 on 05/07/01 = Scene_ID 7046026000112750Index 4 for Path 46/Row 27 on 05/31/01 = Scene_ID 5046027000115110Index 5 for Path 46/Row 28 on 04/10/00 = Scene_ID 5046028000010110Index 6 for Path 47/Row 26 on 02/13/00 = Scene_ID 5047026000004410Index 7 for Path 47/Row 27 on 02/26/02 = Scene_ID 7047027000205750Index 7 for Path 47/Row 28 on 02/26/02 = Scene_ID 7047028000205750Index 8 for Path 48/Row 26 on 04/03/01 = Scene_ID 7048026000109350Index 8 for Path 48/Row 27 on 04/03/01 = Scene_ID 7048027000109350LEAF ON (Summer)-Index 1 for Path 45/Row 26 on 07/16/00 = Scene_ID 7045026000019850Index 2 for Path 45/Row 27 on 07/22/02 = Scene_ID 7045027000220350Index 1 for Path 45/Row 28 on 07/16/00 = Scene_ID 7045028000019850Index 3 for Path 46/Row 26 on 08/11/01 = Scene_ID 7046026000122350Index 4 for Path 46/Row 27 on 07/07/00 = Scene_ID 7046027000018950Index 4 for Path 46/Row 28 on 07/07/00 = Scene_ID 7046028000018950Index 5 for Path 47/Row 26 on 07/30/00 = Scene_ID 7047026000021250Index 5 for Path 47/Row 27 on 07/30/00 = Scene_ID 7047027000021250Index 6 for Path 47/Row 28 on 07/01/01 = Scene_ID 7047028000118250Index 7 for Path 48/Row 26 on 07/21/00 = Scene_ID 7048026000020350Index 8 for Path 48/Row 27 on 06/03/00 = Scene_ID 7048027000015550LEAF-OFF (Fall)-Index 1 for Path 45/Row 26 on 10/18/99 = Scene_ID 7045026009929150Index 2 for Path 45/Row 27 on 10/04/00 = Scene_ID 7045027000027850Index 3 for Path 45/Row 28 on 08/17/00 = Scene_ID 7045028000023050Index 4 for Path 46/Row 26 on 09/12/01 = Scene_ID 7046026000125550Index 5 for Path 46/Row 27 on 09/25/00 = Scene_ID 7046027000026950Index 5 for Path 46/Row 28 on 09/25/00 = Scene_ID 7046028000026950Index 6 for Path 47/Row 26 on 10/05/01 = Scene_ID 7047026000127850Index 7 for Path 47/Row 27 on 11/01/99 = Scene_ID 7047027009930550Index 8 for Path 47/Row 28 on 10/16/99 = Scene_ID 7047028009928950Index 9 for Path 48/Row 26 on 09/23/00 = Scene_ID 7048026000026750Index 9 for Path 48/Row 27 on 09/23/00 = Scene_ID 7048027000026750Landsat data and ancillary data used for the tree canopy -Data Type of DEM composed of 1 band of Continuous Variable Type.Data Type of Slope composed of 1 band of Continuous Variable Type.Data Type of Aspect composed of 1 band of Categorical Variable Type.Data type of Position Index composed of 1 band of Continuous Variable Type.

    Person who carried out this activity:

    U.S. Geological Survey
    Customer Service Representative
    National Center, 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 this NLCD mapping zone can be directed to the NLCD 2001 land cover mapping team at the National Center, EROS, Sioux Falls, SD (605) 594-6151 or mrlc@usgs.gov.
    Data sources used in this process:
    • Landsat ETM, DEM

    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?

    Regression tree algorithms employed in NLCD 2001 mapping offer a cross-validation option for assessing classification and prediction reliability. Cross-validation can provide relatively reliable estimates for tree canopy predictions if the reference data used for cross-validation are collected based on a statistically valid sampling design. For mapping zone 01 tree canopy modeling, a 5-fold cross-validation was conducted by dividing the entire training data set into 5 subsets of equal size. For each model run, an accuracy estimate was derived using one subset to evaluate the model prediction (with the model developed using the remaining training samples). This process was repeated 5 times. After all 5 runs, an average value of all accuracy estimates and standard errors from the 5 runs were computed. Users should be cautioned that these cross-validation results provide users with only first-order estimates of data quality, and should not be considered a formal accuracy assessment.

  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 Tree Canopy layer is the version dated 10-01-2004.

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

    Nineteen 1-m resolution DOQQs across mapping zone 01 were classified into either tree canopy or non-tree canopy areas, and then values summed within each 30 meter Landsat pixel cell to obtain the percentage of tree canopy.


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
    National Center, 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 National Center, 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: 26-Jul-2005
Metadata author:
U.S. Geological Survey
Customer Services Representative
National Center, 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 12:34:28 2013