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.
The USGS acknowledges the support of the United States Department of Agriculture (USDA), the United States Forest Service (USFS), the International Institute of Tropical Forestry(IITF), and the National Oceanic and Atmospheric Administration (NOAA) in development of data in this zone.
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. The Commonwealth of Puerto Rico Mapping zone encompasses the whole territory of Puerto Rico. Questions about the Commonwealth of Puerto Rico NLCD mapping zone 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.
By combining the training data with Landsat spectral data and other ancillary data, percent imperviousness prediction models were developed using a regression tree algorithm (named "Cubist"). All data layers used as input for running the Cubist in order to establish the prediction model for imperviousness are listed in the "Supplemental Information" section. Three ancillary data sets were used for urban/suburban delineation masking, which is essential to confine the imperviousness mapping within the developed areas.
After the best combination of possible input data layers had been determined and the final percent impervious layer produced, the urban mask created was used to eliminate those pixels from the final percent impervious file that fall outside identified impervious surface areas. Thus, the impervious pixels identified within the mask were retained, while all non-impervious surface pixels were removed from the final product. This corrected for any small areas of pixels that may have been included as part of the impervious surface layer because their spectral signature was not covered in the Cubist modeling process. Finally, visual inspection of imperviousness layer was made with limited manual editing to eliminate non-urban areas based on area of interest delineated by the mapping team.
Acquisition dates of Landsat ETM+ (TM) scenes used for land cover classification in Commonwealth of Puerto Rico zone are as follows:
Index 1 For Path 04 /Row 48 on 03/27/00 = Scene ID 7004048000008710
Index 2 For Path 04 /Row 47 on 02/26/01 = Scene ID 7004047000105750
Index 3 For Path 05 /Row 48 on 11/13/00 = Scene ID 7005048000031810
Index 4 For Path 05 /Row 47 on 01/22/03 = Scene ID 7005047000302250
Index 5 For Path 05 /Row 47 on 11/27/99 = Scene ID 7005047009933110
Index 6 histogram_match
Landsat data and ancillary data used for the imperviousness prediction -
Data Type of DEM composed of 1 band and a Continuous Variable Type.
Data Type of Slope composed of 1 band and a 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.
Ancillary data used for urban area masking include: 1. NOAA Defense Meteorological Satellite Program 1 km city light data (1 band) 2. MRLC 1992 classification (1 band) 3. TIGER 2000 roads (1 band)