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 Sanborn Map Company 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. Mapping zone 27 encompasses whole or portions of several states including New Mexico, Colorado, Texas, and Oklahoma. Questions about the NLCD mapping zone 27 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 zone 27 are as follows:
Spring-
Index 1 for Path 31/Row 34 on 05/11/00 = Scene_ID 7031034000013250
Index 2 for Path 31/Row 35 on 11/01/99 = Scene_ID 7031035009930550
Index 2 for Path 31/Row 36 on 11/01/99 = Scene_ID 7031036009930550
Index 3 for Path 31/Row 37 on 04/25/00 = Scene_ID 7031037000011650
Index 4 for Path 32/Row 33 on 04/16/00 = Scene_ID 7032033000010750
Index 4 for Path 32/Row 34 on 04/16/00 = Scene_ID 7032034000010750
Index 4 for Path 32/Row 35 on 04/16/00 = Scene_ID 7032035000010750
Index 4 for Path 32/Row 36 on 04/16/00 = Scene_ID 7032036000010750
Index 4 for Path 32/Row 37 on 04/16/00 = Scene_ID 7032037000010750
Index 5 for Path 33/Row 33 on 03/28/02 = Scene_ID 7033033000208750
Index 5 for Path 33/Row 34 on 03/28/02 = Scene_ID 7033034000208750
Index 5 for Path 33/Row 35 on 03/28/02 = Scene_ID 7033035000208750
Index 6 for Path 33/Row 36 on 05/09/00 = Scene_ID 7033036000013050
Index 7 for Path 33/Row 37 on 04/07/00 = Scene_ID 7033037000009850
Leaf-On (Summer)-
Index 1 for Path 31/Row 33 on 10/18/00 = Scene_ID 7031033000029250
Index 2 for Path 31/Row 34 on 06/15/01 = Scene_ID 7031034000116650
Index 3 for Path 31/Row 35 on 08/13/99 = Scene_ID 7031035009922550
Index 3 for Path 31/Row 36 on 08/13/99 = Scene_ID 7031036009922550
Index 4 for Path 31/Row 37 on 09/30/99 = Scene_ID 7031037009927350
Index 5 for Path 32/Row 33 on 06/06/01 = Scene_ID 7032033000115750
Index 6 for Path 32/Row 34 on 09/07/00 = Scene_ID 7032034000025150
Index15 for Path 32/Row 34 on 06/22/01 = Scene_ID 7032034000117350
Index 6 for Path 32/Row 35 on 09/07/00 = Scene_ID 7032035000025150
Index 6 for Path 32/Row 36 on 09/07/00 = Scene_ID 7032036000025150
Index 6 for Path 32/Row 37 on 09/07/00 = Scene_ID 7032037000025150
Index 7 for Path 32/Row 37 on 10/23/99 = Scene_ID 7032037009929650
Index 8 for Path 33/Row 33 on 08/13/00 = Scene_ID 7033033000022650
Index13 for Path 33/Row 33 on 10/16/00 = Scene_ID 7033033000029050
Index 9 for Path 33/Row 34 on 07/10/99 = Scene_ID 7033034009919150
Index10 for Path 33/Row 34 on 07/02/02 = Scene_ID 7033034000218350
Index11 for Path 33/Row 35 on 09/14/00 = Scene_ID 7033035000025850
Index12 for Path 33/Row 36 on 05/31/02 = Scene_ID 7033036000215150
Index14 for Path 33/Row 36 on 09/28/99 = Scene_ID 7033036009927150
Leaf-Off (Fall)-
Index 1 for Path 31/Row 34 on 10/18/00 = Scene_ID 7031034000029250
Index 2 for Path 31/Row 35 on 11/01/99 = Scene_ID 7031035009930550
Index 2 for Path 31/Row 36 on 11/01/99 = Scene_ID 7031036009930550
Index 2 for Path 31/Row 37 on 11/01/99 = Scene_ID 7031037009930550
Index 3 for Path 32/Row 33 on 10/09/00 = Scene_ID 7032033000028350
Index 8 for Path 32/Row 33 on 04/16/00 = Scene_ID 7032033000010750
Index 4 for Path 32/Row 34 on 10/23/99 = Scene_ID 7032034009929650
Index 4 for Path 32/Row 35 on 10/23/99 = Scene_ID 7032035009929650
Index 4 for Path 32/Row 36 on 10/23/99 = Scene_ID 7032036009929650
Index 4 for Path 32/Row 37 on 10/23/99 = Scene_ID 7032037009929650
Index 5 for Path 33/Row 33 on 10/16/00 = Scene_ID 7033033000029050
Index 6 for Path 33/Row 34 on 10/14/99 = Scene_ID 7033034009928750
Index 6 for Path 33/Row 35 on 10/14/99 = Scene_ID 7033035009928750
Index 7 for Path 33/Row 36 on 10/30/99 = Scene_ID 7033036009930350
Index 7 for Path 33/Row 37 on 10/30/99 = Scene_ID 7033037009930350
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)