This is a digital landuse dataset for the state of Oklahoma. These data can be used in a geographic information system (GIS) for many of purposes such as assessing wildlife habitat, water quality, pesticide runoff, and land-use change. The State datasets are provided with a 300-meter buffer beyond the State border to faciliate combining the State files into larger regions. The user must have a firm understanding of how the datasets were compiled and the resulting limitations of these data. The National Land Cover Dataset (NLCD) was compiled from Landsat satellite Thematic Mapper (TM) imagery (circa 1992) with a spatial resolution of 30 meters and supplemented by various ancillary data (where available). The analysis and interpretation of the satellite imagery was conducted by using very large, sometimes multistate image mosaics (as much as 18 Landsat scenes). by using a relatively small number of aerial photographs for "ground truth", the thematic interpretations were necessarily conducted from a spatially-broad perspective. Furthermore, the accuracy assessments (see Attribute Accuracy) correspond to "federal regions" that are groupings of contiguous states. Thus, the reliability of the data is greatest at the state or multistate level. The statistical accuracy of the data is known only for the region. Important Caution Advisory Users are cautioned to carefully scrutinize the data to see if these data are of sufficient reliability before attempting to use the dataset for larger-scale or local analyses. This evaluation must be made remembering that the NLCD represents conditions in the early 1990s. The Oklahoma part of the NLCD was created as part of land-cover mapping activities for Federal Region VI, which includes the States of Texas, New Mexico, Arkansas, Oklahoma and Louisiana. The NLCD classification contains 21 different land-cover categories with a spatial resolution of 30 meters. The NLCD was produced as a cooperative effort between the U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (USEPA) to produce a consistent, land-cover data layer for the conterminous United States by using early 1990s Landsat TM data purchased by the Multi-resolution Land Characterization (MRLC) Consortium. The MRLC Consortium is a partnership of federal agencies that produce or use land-cover data. Partners include, but not limited to, the USGS (National Mapping, Biological Resources, and Water Resources Divisions), USEPA, the U.S. Forest Service, and the National Oceanic and Atmospheric Administration.
The main objective of this project was to produce a generalized and nationally consistent land-cover data layer for the entire conterminous United States. These data can be used as a layer in a GIS for many purposes such assessing wildlife habitat, water quality, pesticide runoff, and land-use change.
The land-cover data files are provided as a "Geo-TIFF". The land-cover datasets are single band raster images. The X/Y corner coordinates (projection coordinates, center of pixel) for Oklahoma are: Upper Left Corner: -621210/1573800 meters, Lower Right Corner: -141600/1172790 meters.
ground condition
None. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
U.S. Geological Survey, EROS Data Center
This work was performed by the Raytheon STX Corporation under U.S. Geological Survey Contract 1434-92-C-40004.
An accuracy assessment is done on all NLCD on a Federal region basis following a revision cycle that incorporates feedback from MRLC partners and affiliated users. The accuracy assessments are conducted by private sector vendors under contract to the USEPA. A protocol has been established by the USGS and USEPA that incorporates a two-stage, geographically stratified cluster sampling plan (Zhu and others, 2000) utilizing National Aerial Photography Program (NAPP) photographs as the sampling frame and the basic sampling unit. In this design a NAPP photograph is defined as a first stage or primary sampling unit (PSU), and a sampled pixel in each PSU is treated as a second stage or secondary sampling unit (SSU). PSUs are selected from a sampling grid based on NAPP flight-lines and photographic centers, each grid cell measures 15' x 15' (minutes of latitude/longitude) and consists of 32 National High Altitude Photography (NHAP) photographs. A geographically stratified random sampling is performed with one NAPP photograph being randomly selected from each cell (geographic strata), if a sampled photograph falls outside of the regional boundary that photograph is not used. Second stage sampling is accomplished by selecting SSUs (pixels) in each PSU (NAPP photograph) to provide the actual locations for the reference land-cover classification. The SSUs are manually interpreted and misclassification errors are estimated and described by using a traditional error matrix as well as a number of measures including the overall proportion of pixels correctly classified, user's and producer's accuracies, and omission and commission error probabilities.
An unsupervised classification algorithm was used to classify the mosaic of multiple leaf-off TM scenes. Aerial photographs were used to interpret and label classes into land-cover categories and ancillary data sources resolved the class confusion. Further land- cover information from leaf-on TM data, National Wetlands Inventory (NWI) data, and other sources were incorporated to refine and augment the "basic" classification.
All photo-interpretable data are mapped.
Each Landsat TM image used to create the NLCD was precision terrain-corrected by by using 3-arc-second digital terrain elevation data (DTED), and georegistered by using ground-control points. This resulted in a root mean square registration error of less than 1 pixel (30 meters).
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provided the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provdes the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the land-cover classification is determined.
The image provides the base from which the lland-cover classification is determined.
Land-Cover Characterization: The project is being carried out by using 10 Federal regions that make up the conterminous United States; each region is composed of multiple states; each region is processed in subregional units that are limited to the area covered by no more than 18 Landsat TM scenes. The general NLCD procedure is to: (1) run a mosaic on subregional TM scenes and classify these scenes by using an unsupervised clustering algorithm, (2) interpret and label the clusters/classes by using aerial photographs as reference data, (3) resolve the labeling of confused clusters/classes by using the appropriate ancillary data source(s), and (4) incorporate land-cover information from other datasets and perform manual edits to augment and refine the "basic" classification developed. Two seasonally distinct TM mosaics are produced, a leaves-on version (summer) and a leaves-off (spring/autumn) version. TM bands 3, 4, 5, and 7 are a mosaic for both the leaves-on and leaves-off versions. For mosaic purposes, a base scene is selected for each mosaic, and the other scenes are adjusted to mimic spectral properties of the base scene by using histogram matching in regions of spatial overlap. Following the mosaic, either the leaves-off version or leaves-on version is selected to be the "base" for the land-cover mapping process. The 4 TM bands of the "base" mosaic are clustered to produce a single 100- class image by using an unsupervised clustering algorithm. Each of the spectrally distinct clusters/classes is then assigned to one or more Anderson level 1 and 2 land-cover classes by using NHAP program and NAPP aerial photographs as a reference. Almost invariably, individual spectral clusters/classes are confused between two or more land-cover classes. Separation of the confused spectral clusters/classes into appropriate NLCD class is accomplished by using ancillary data layers. Standard ancillary data layers include: the "nonbase" mosaic TM bands and 100- class cluster image; derived TM normalized vegetation index, various TM band ratios, TM date bands; 3-arc second DTED and derived slope, aspect and shaded relief; population and housing density data; USGS land use and land cover; and NWI data, if available. Other ancillary data sources may include soils data, unique state or regional land-cover datasets, or data from other federal programs such as the National Gap Analysis Program of the USGS Biological Resources Discipline. For a given confused spectral cluster/class, digital values of the various ancillary data layers are compared to determine: (1) which data layers are the most effective for splitting the confused cluster/class into the appropriate NLCD class, and (2) the appropriate layer thresholds for making the split(s). Models are then developed by using one to several ancillary data layers to split the confused cluster/class into the NLCD class. For example, a population density threshold is used to separate high-intensity residential areas from commercial/industrial/transportation areas. Or a cluster/class might be confused between row crop and grasslands. To split this particular cluster/class, a TM normalized vegetation index threshold might be identified and used with an elevation threshold in a class-splitting model to make the appropriate NLCD class assignments. A purely spectral example is by using the temporally opposite TM layers to discriminate confused cluster/classes such as hay pasture vs. row crops and deciduous forests vs. evergreen forests; simple thresholds that contrast the seasonal differences in vegetation between leaves-on vs. leaves-off. Not all cluster/class confusion can be successfully modeled out. Certain classes such as urban/recreational grasses or quarries/strip mines/gravel pits that are not spectrally unique require manual editing. These class features are typically visually identified and then reclassified by using on-screen digitizing and recoding. Other classes such as wetlands require the use of specific datasets such as NWI to provide the most accurate classification. Areas lacking NWI data are typically subset out and modeling is used to estimate wetlands in these localized areas. The final NLCD product results from the classification (interpretation and labeling) of the 100-class "base" cluster mosaic by using automated and manual processes, incorporating spectral and conditional data layers. For a more detailed explanation please see Vogelmann and others, 1998a and Vogelmann and others, 1998b. Discussion: While the authors believe that the approach taken has yielded a good general land-cover classification product for the nation, it is important to indicate to the user where there might be some potential problems. The biggest concerns are listed below: 1) Some of the TM datasets are not temporally ideal. Leaves-off datasets are heavily relied upon for discriminating between hay/pasture and row crop, and also for discriminating between forest classes. The success of discriminating between these classes by using leaves-off datasets hinges on the time of data acquisition. When hay/pasture areas are nongreen, these areas are not easily distinguishable from other agricultural areas by using remotely sensed data. However, there is a temporal window during which hay and pasture areas green up before most other vegetation (excluding evergreens, which have different spectral properties); during this window these areas are easily distinguishable from other crop areas. The discrimination between hay/pasture and deciduous forest is likewise optimized by selecting data in a temporal window where deciduous vegetation has yet to leaf out. Single-date of imagery (leaves-on or leaves-off) is difficult to acquire so that adequately differentiates between deciduous/hay and pasture and hay pasture/row crop. 2) The datasets used cover a range of years (see data sources), and changes that have taken place across the landscape over the time period may not have been captured. While this is not viewed as a major problem for most classes, possibly some land-cover features change more rapidly than might be expected (for example, hay one year, row crop the next). 3) Wetlands classes are extremely difficult to extract from Landsat TM spectral information alone. The use of ancillary information such as NWI data are highly desirable. The authors relied on the National Gap Analysis Program and USGS Land Use and Land Cover, or proximity to streams and rivers as well as spectral data to delineate wetlands in areas without NWI data. 4) Separation of natural grass and shrub is problematic. Areas observed on the ground to be shrub or grass are not always distinguishable spectrally. Likewise, there was often disagreement between National Gap Analysis Program and USGS Land Use and Land Cover on these classes. Acknowledgments This work was performed under contract the U.S. Geological Survey (Contract 1434-CR-97-CN-40274). References More detailed information on the methodologies and techniques employed in this work can be found in the following: Kelly, P.M., and White, J.M., 1993, Preprocessing remotely sensed data for efficient analysis and classification, Applications of Artificial Intelligence 1993: Knowledge-Based Systems in Aerospace and Industry, Proceeding of SPIE, 1993, p. 24-30. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe, 1979, Classification of Wetlands and Deepwater Habitats of the United States, Fish and Wildlife Service: U.S. Department of the Interior. Vogelmann, J.E., Sohl, T., and Howard, S.M., 1998a, Regional Characterization of Land Cover by using Multiple Sources of Data: Photogrammetric Engineering & Remote Sensing, v. 64, no. 1, p. 45-57. Vogelmann, J.E., Sohl, T., Campbell, P.V., and Shaw, D.M., 1998b, Regional Land Cover Characterization by using Landsat Thematic Mapper Data and Ancillary Data Sources: Environmental Monitoring and Assessment, v. 51, p. 415-428. Zhu, Z., Yang, L., Stehman, S., and Czaplewski, R., 1999, Designing an Accuracy Assessment for USGS Regional Land Cover Mapping Program: Photogrametric Engineering & Remote Sensing, v.66, no.12, p.1425-1435.
U.S. Geological Survey EROS Data Center
Internal feature number.
ESRI
NOTE - All classes may NOT be represented in a specific state dataset. The class number represents the digital value of the class in the dataset. Water 11 Open Water 12 Perennial Ice/Snow Developed 21 Low Intensity Residential 22 High Intensity Residential 23 Commercial/Industrial/Transportation Barren 31 Bare Rock/Sand/Clay 32 Quarries/Strip Mines/Gravel Pits 33 Transitional Vegetated; Natural Forested Upland 41 Deciduous Forest 42 Evergreen Forest 43 Mixed Forest Shrubland 51 Shrubland Non-natural Woody 61 Orchards/Vineyards/Other Herbaceous Upland 71 Grasslands/Herbaceous Herbaceous Planted/Cultivated 81 Pasture/Hay 82 Row Crops 83 Small Grains 84 Fallow 85 Urban/Recreational Grasses Wetlands 91 Woody Wetlands 92 Emergent Herbaceous Wetlands NLCD Land Cover Classification System Land Cover Class Definitions: Water - all areas of open water or permanent ice/snow cover. 11. Open Water - areas of open water, generally with less than 25 percent or greater cover of water (per pixel). 12. Perennial Ice/Snow - all areas characterized by year-long cover of ice and/or snow. Developed - areas characterized by high percentage (about 30 percent or greater) of constructed materials (for example, asphalt, concrete, or buildings). 21. Low Intensity Residential - Includes areas with a mixture of constructed materials and vegetation. Constructed materials account for 30-80 percent of the cover. Vegetation may account for 20 to 70 percent of the cover. These areas most commonly include single-family housing units. Population densities will be lower than in high intensity residential areas. 22. High Intensity Residential - Includes heavily built-up urban centers where people reside in high numbers. Examples include apartment complexes and row houses. Vegetation accounts for less than 20 percent of the cover. Constructed materials account for 80-100 percent of the cover. 23. Commercial/Industrial/Transportation - Includes infrastructure (for example, roads or railroads) and all highways and all developed areas not classified as High Intensity Residential. Barren - Areas characterized by bare rock, gravel, sand, silt, clay, or other earthen material, with little or no "green" vegetation present regardless of the inherent ability to support life. Vegetation, if present, is more widely spaced and scrubby than that in the "green"vegetated categories; lichen cover may be extensive. 31. Bare Rock/Sand/Clay - Perennially barren areas of bedrock, desert, pavement, scarps, talus, slides, volcanic material, glacial debris, and other accumulations of earthen material. 32. Quarries/Strip Mines/Gravel Pits - Areas of extractive mining activities with substantial surface expression. 33. Transitional - Areas of sparse vegetative cover (less than 25 percent that are dynamically changing from one land cover to another, often because of land-use activities. Examples include forest clearcuts, a transition phase between forest and agricultural land, the temporary clearing of vegetation, and changes because of natural causes (for example, fire or flood). Forested Upland - Areas characterized by tree cover (natural or seminatural woody vegetation, generally greater than 6-meters tall); Tree canopy accounts for 25-100 percent of the cover. 41. Deciduous Forest - Areas dominated by trees where 75 percent or more of the tree species shed foliage simultaneously in response to seasonal change. 42. Evergreen Forest - Areas characterized by trees where 75 percent or more of the tree species maintain leaves all year. Canopy is never without green foliage. 43. Mixed Forest - Areas dominated by trees where neither deciduous nor evergreen species represent more than 75 percent of the cover present. Shrubland - Areas characterized by natural or seminatural woody vegetation with aerial stems, generally less than 6-meters tall with individuals or clumps not touching to interlocking. Both evergreen and deciduous species of true shrubs, young trees, and trees or shrubs that are small or stunted because of environmental conditions are included. 51. Shrubland - Areas dominated by shrubs; shrub canopy accounts for 25-100 percent of the cover. Shrub cover is generally greater than 25 percent when tree cover is less than 25 percent. Shrub cover may be less than 25 percent in cases when the cover of other plant forms (for example, herbaceous or tree) is less than 25 percent and shrubs cover exceeds the cover of the other plant forms. Non-natural Woody - Areas dominated by non-natural woody vegetation; non-natural woody vegetative canopy accounts for 25-100 percent of the cover. The non-natural woody classification is subject to the availability of sufficient ancillary data to differentiate non-natural woody vegetation from natural woody vegetation. 61. Orchards/Vineyards/Other - Orchards, vineyards, and other areas planted or maintained for the production of fruits, nuts, berries, or ornamentals. Herbaceous Upland - Upland areas characterized by natural or seminatural herbaceous vegetation; herbaceous vegetation accounts for 75-100 percent of the cover. 71. Grasslands/Herbaceous - Areas dominated by upland grasses and forbs. In rare cases, herbaceous cover is less than 25 percent, but exceeds the combined cover of the woody species present. These areas are not subject to intensive management, but are often utilized for grazing. Planted/Cultivated - Areas characterized by herbaceous vegetation that has been planted or is intensively managed for the production of food, feed, or fiber; or is maintained in developed settings for specific purposes. Herbaceous vegetation accounts for 75-100 percent of the cover. 81. Pasture/Hay - Areas of grasses, legumes, or grass-legume mixtures planted for livestock grazing or the production of seed or hay crops. 82. Row Crops - Areas used for the production of crops, such as corn, soybeans, vegetables, tobacco, and cotton. 83. Small Grains - Areas used for the production of graminoid crops such as wheat, barley, oats, and rice 84. Fallow - Areas used for the production of crops that are temporarily barren or with sparse vegetative cover as a result of being tilled in a management practice that incorporates prescribed alternation between cropping and tillage. 85. Urban/Recreational Grasses - Vegetation (primarily grasses) planted in developed settings for recreation, erosion control, or aesthetic purposes. Examples include parks, lawns, golf courses, airport grasses, and industrial site grasses. Wetlands - Areas where the soil or substrate is periodically saturated with or covered with water as defined by Cowardin and others, 1979. 91. Woody Wetlands - Areas where forest or shrubland vegetation accounts for 25-100 percent of the cover and the soil or substrate is periodically saturated with or covered with water. 92. Emergent Herbaceous Wetlands - Areas where perennial herbaceous vegetation accounts for 75-100 percent of the cover and the soil or substrate is periodically saturated with or covered with water.
NLCD Regional Land Cover Classification System Key Rev. 11/98
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.
GeoTIFF is a standard for storing georeference and geocoding information in a TIFF 6.0 compliant raster file (uncompressed).
NLCD data may be obtained in the following ways: 1. Contacting the nearest Digital Cartographic Data Business Partner (GeoTIFF CD-ROM products only). A list of the Business Partners is available at: http://mapping.usgs.gov/www/partners/bpmain.html; 2. Calling 1-888-ASK-USGS 3. Ordering online via the USGS Earth Explorer at: http://edcsns17.cr.usgs.gov/EarthExplorer/ 4. Visiting and ordering online through the MRLC Consortium Viewer and Downloader at: http://gisdata.usgs.net/website/MRLC/viewer.htm
U.S. Geological Survey EROS Data Center