USDA, National Agricultural Statistics Service, 2007 Iowa Cropland Data Layer

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator:
United States Department of Agriculture (USDA), National Agricultural Statistics Service (NASS), Research and Development Division (RDD), Geospatial Information Branch (GIB), Spatial Analysis Research Section (SARS)
Publication_Date: 20080306
Title:
USDA, National Agricultural Statistics Service, 2007 Iowa Cropland Data Layer
Edition: 2007 Edition
Geospatial_Data_Presentation_Form: raster digital data
Publication_Information:
Publication_Place:
USDA, NASS Marketing and Information Services Office, Washington, D.C.
Publisher: USDA, NASS
Other_Citation_Details:
Available on DVD through the official website <http://www.nass.usda.gov/research/Cropland/SARS1a.htm>. The data is also available free for download through the Geospatial Data Gateway at <http://datagateway.nrcs.usda.gov/>. See the 'Ordering Instructions' section of this metadata file for detailed download instructions.

The official DVD contains additional accuracy assessment information that is not available through the Geospatial Data Gateway in the form of an associated confidence layer. The following description of the confidence layer is taken from the document entitled 'MDA_NLCD_User_Guide.doc' which is available free for download with the NLCD Mapping Tool at <http://www.mrlc.gov/>. The Confidence Layer "spatially represents the predicted confidence that is associated with that output pixel, based upon the rule(s) that were used to classify it. This is useful in that the user can see the spatial representation of distribution and magnitude of error or confidence for a given classification... This error layer represents a percent confidence associated with each rule and output categorical, classified value. It is expressed as a percentage of confidence. A value of zero would therefore have a low confidence (always wrong), while a value of 100 would have a very high confidence (always right)." For more information on the use of confidence layers please refer to the following paper: Liu, Weiguo, Sucharita Gopal and Curtis E. Woodcock, 2004. Uncertainty and confidence in land cover classification using a hybrid classifier approach, Photogrammetric Engineering & Remote Sensing, 70(8):963-971. Ultimately, however, the confidence value is not a measure of accuracy for a given pixel but rather a how well it fit within the decision tree ruleset.
Online_Linkage: <http://datagateway.nrcs.usda.gov/>
Description:
Abstract:
The USDA, NASS Cropland Data Layer (CDL) is a raster, geo-referenced, crop-specific land cover data layer with a ground resolution of 56 meters. The CDL is produced using satellite imagery from the Indian Remote Sensing RESOURCESAT-1 (IRS-P6) Advanced Wide Field Sensor (AWiFS) collected during the current growing season. Ancillary classification inputs include: the United States Geological Survey (USGS) National Elevation Dataset (NED), the USGS National Land Cover Dataset 2001 (NLCD 2001), and the National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) 250 meter 16 day Normalized Difference Vegetation Index (NDVI) composites. Agricultural training and validation data are derived from the Farm Service Agency (FSA) Common Land Unit (CLU) Program. The NLCD 2001 is used as non-agricultural training and validation data. The strength and emphasis of the CDL is agricultural land cover. Please note that no farmer reported data are derivable from the Cropland Data Layer.
Purpose:
The purpose of the Cropland Data Layer Program is to use satellite imagery to (1) provide acreage estimates to the Agricultural Statistics Board for the state's major commodities and (2) produce digital, crop-specific, categorized geo-referenced output products.
Supplemental_Information:
If the following table does not display properly, then please visit this internet site <http://www.nass.usda.gov/research/Cropland/metadata/meta.htm> to view the original metadata file. 
USDA, National Agricultural Statistics Service 2007 Iowa Cropland Data Layer

CLASSIFICATION INPUTS:
AWIFS DATE 20070430 PATH 271 ROW(S)&QUADRANT(S) 40ABCD 45D
AWIFS DATE 20070613 PATH 275 ROW(S)&QUADRANT(S) 35CD 40ABCD 45ABCD 50B
AWIFS DATE 20070706 PATH 270 ROW(S)&QUADRANT(S) 35C 40ABCD
AWIFS DATE 20070707 PATH 275 ROW(S)&QUADRANT(S) 35C 40ABCD 45A
AWIFS DATE 20070720 PATH 268 ROW(S)&QUADRANT(S) 35ABCD 40AB
AWIFS DATE 20070721 PATH 273 ROW(S)&QUADRANT(S) 35CD 40ABCD 45BD
AWIFS DATE 20070731 PATH 275 ROW(S)&QUADRANT(S) 35CD 40ABCD
AWIFS DATE 20070813 PATH 268 ROW(S)&QUADRANT(S) 35D 40ABCD 45ABD
AWIFS DATE 20070827 PATH 266 ROW(S)&QUADRANT(S) 40BCD 45AB
AWIFS DATE 20070828 PATH 271 ROW(S)&QUADRANT(S) 35D 40BCD 45AB
AWIFS DATE 20070901 PATH 267 ROW(S)&QUADRANT(S) 35BD 40BD 45B
AWIFS DATE 20070902 PATH 272 ROW(S)&QUADRANT(S) 35D 40BD 45B

MODIS 16 DAY NDVI COMPOSITE DATE 20070101
MODIS 16 DAY NDVI COMPOSITE DATE 20070117
MODIS 16 DAY NDVI COMPOSITE DATE 20070202
MODIS 16 DAY NDVI COMPOSITE DATE 20070218
MODIS 16 DAY NDVI COMPOSITE DATE 20070306
MODIS 16 DAY NDVI COMPOSITE DATE 20070322
MODIS 16 DAY NDVI COMPOSITE DATE 20070407
MODIS 16 DAY NDVI COMPOSITE DATE 20070423
MODIS 16 DAY NDVI COMPOSITE DATE 20070509
MODIS 16 DAY NDVI COMPOSITE DATE 20070525
MODIS 16 DAY NDVI COMPOSITE DATE 20070610
MODIS 16 DAY NDVI COMPOSITE DATE 20070626
MODIS 16 DAY NDVI COMPOSITE DATE 20070712
MODIS 16 DAY NDVI COMPOSITE DATE 20070728
MODIS 16 DAY NDVI COMPOSITE DATE 20070813

USGS, NATIONAL ELEVATION DATASET ELEVATION
USGS, NATIONAL LAND COVER DATASET 2001 TREE CANOPY
USGS, NATIONAL LAND COVER DATASET 2001 IMPERVIOUSNESS

TRAINING AND VALIDATION:
USDA, FARM SERVICE AGENCY 2007 COMMON LAND UNITS
USGS, NATIONAL LAND COVER DATASET 2001

NOTE: The final extent of the CDL is clipped to the state boundary
even though the raw input data may encompass a larger area.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20070401
Ending_Date: 20070930
Currentness_Reference: 2007 growing season
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -96.8009
East_Bounding_Coordinate: -90.1585
North_Bounding_Coordinate: 43.5806
South_Bounding_Coordinate: 40.3255
Keywords:
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: farming, 001
Theme_Keyword: environment, 007
Theme_Keyword: imageryBaseMapsEarthCover, 010
Theme:
Theme_Keyword_Thesaurus: Global Change Master Directory (GCMD) Science Keywords
Theme_Keyword:
Earth Science > Biosphere > Terrestrial Ecosystems > Agricultural Lands
Theme_Keyword: Earth Science > Land Surface > Land Use/Land Cover > Land Cover

Theme:
Theme_Keyword_Thesaurus: Global Change Master Directory (GCMD) Instrument Keywords
Theme_Keyword: AWIFS > Advanced Wide Field Sensor
Theme_Keyword: MODIS > Moderate-Resolution Imaging Spectroradiometer

Theme:
Theme_Keyword_Thesaurus: None

Theme_Keyword: crop cover
Theme_Keyword: cropland
Theme_Keyword: agriculture
Theme_Keyword: land cover
Theme_Keyword: crop estimates
Theme_Keyword: AWiFS
Theme_Keyword: MODIS
Place:
Place_Keyword_Thesaurus: Global Change Master Directory (GCMD) Location Keywords
Place_Keyword: Continent > North America > United States of America > Iowa
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Iowa
Place_Keyword: IA
Temporal:
Temporal_Keyword_Thesaurus: None
Temporal_Keyword: 2007
Access_Constraints: None
Use_Constraints:
The USDA, NASS Cropland Data Layer is provided to the public as is and is considered public domain and free to redistribute. The USDA, NASS does not warrant any conclusions drawn from these data. If the user does not have software capable of viewing GEOTIF (.tif) or ERDAS Imagine (.img) file formats then we suggest using the freeware browser ESRI ArcReader <http://www.esri.com/arcreader/>.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USDA, NASS, Spatial Analysis Research Section
Contact_Person: USDA, NASS, Spatial Analysis Research Section staff
Contact_Address:
Address_Type: mailing and physical address
Address: 3251 Old Lee Highway, Room 305
City: Fairfax
State_or_Province: Virginia
Postal_Code: 22030-1504
Country: USA
Contact_Voice_Telephone: 703-877-8000
Contact_Facsimile_Telephone: 703-877-8044
Contact_Electronic_Mail_Address: HQ_RD_GIB@nass.usda.gov
Data_Set_Credit: USDA, National Agricultural Statistics Service
Security_Information:
Security_Classification_System: None
Security_Classification: Unclassified
Security_Handling_Description: None
Native_Data_Set_Environment:
Microsoft Windows XP; Leica Geosystems ERDAS Imagine 9.1 <http://gi.leica-geosystems.com/>; ESRI ArcGIS Version 9.1 and 9.2 with Service Pack 3 <http://www.esri.com/>; Rulequest See5.0 Release 2.04 <http://www.rulequest.com/>; NLCD Mapping Tool <http://www.mrlc.gov/>.
Leica Geosystems ERDAS Imagine is used in the pre- and post- processing of all raster-based data. ESRI ArcGIS is used to prepare the vector-based Farm Service Agency (FSA) Common Land Unit (CLU) training and validation data. Rulequest See5.0 is used to create a decision-tree based classifier. The NLCD Mapping Tool is used to apply the See5.0 decision-tree via ERDAS Imagine. This is a departure from older versions of the CDL that were classified using in-house software (Peditor) based upon a maximum likelihood classifier approach. Check this section and the 'Process Description' section of the specific state and year metadata file to verify what methodology was used.
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
If the following table does not display properly, then please visit this internet site <http://www.nass.usda.gov/research/Cropland/metadata/meta.htm> to view the original metadata file. 
USDA, National Agricultural Statistics Service, 2007 Iowa Cropland Data Layer
STATEWIDE AGRICULTURAL ACCURACY REPORT

Crop-specific covers only  *Correct  Accuracy   Error   Kappa
-------------------------   -------  --------   -----   -----
OVERALL ACCURACY            4275554    97.20%   2.80%  0.9394


Cover              Attribute  *Correct  Producer's  Omission            User's  Commission  Cond'l
Type                    Code    Pixels   Accuracy     Error    Kappa  Accuracy      Error    Kappa
----                    ----    ------   --------     -----    -----  --------      -----    -----
Corn                      1    2835153     97.53%     2.47%    0.9507   97.57%     2.43%    0.9514
Sorghum                   4          1    100.00%     0.00%    1.0000    0.66%    99.34%    0.0066
Soybeans                  5    1423270     97.02%     2.98%    0.9601   96.74%     3.26%    0.9564
Sunflowers                6          0       n/a       n/a       n/a     0.00%   100.00%    0.0000
Barley                   21          8     88.89%    11.11%    0.8889    2.81%    97.19%    0.0281
Spring Wheat             23          4     21.05%    78.95%    0.2105    2.15%    97.85%    0.0215
Winter Wheat             24        297     67.19%    32.81%    0.6718   14.94%    85.06%    0.1493
Other Small Grains       25          0       n/a       n/a       n/a     0.00%   100.00%    0.0000
Win Wht/Soyb Dbl Crop    26          0      0.00%   100.00%    0.0000    0.00%   100.00%    0.0000
Rye                      27         46     62.16%    37.84%    0.6216   26.90%    73.10%    0.2690
Oats                     28       1708     63.00%    37.00%    0.6296   26.07%    73.93%    0.2604
Millet                   29          0      0.00%   100.00%    0.0000    0.00%   100.00%    0.0000
Alfalfa                  36      14737     69.13%    30.87%    0.6887   30.49%    69.51%    0.3023
Dry Beans                42         34     89.47%    10.53%    0.8947   31.48%    68.52%    0.3148
Potatoes                 43         12     92.31%     7.69%    0.9231   19.05%    80.95%    0.1905
Other Crops              44          0      0.00%   100.00%    0.0000    0.00%   100.00%    0.0000
Misc Vegs & Fruits       47        256     79.01%    20.99%    0.7900    7.00%    93.00%    0.0700
Watermelon               48          1     33.33%    66.67%    0.3333    1.35%    98.65%    0.0135
Peas                     53         24     92.31%     7.69%    0.9231   27.59%    72.41%    0.2759
Clover/Wildflowers       58          3     27.27%    72.73%    0.2727    0.51%    99.49%    0.0051
Fallow/Idle Cropland     61          0      0.00%   100.00%   -0.0001    0.00%   100.00%    0.0000
Apples                   68          0      0.00%   100.00%    0.0000    0.00%   100.00%    0.0000
Grapes                   69          0       n/a       n/a       n/a     0.00%   100.00%    0.0000
Christmas Trees          70          0       n/a       n/a       n/a     0.00%   100.00%    0.0000
Other Tree Nuts & Fruit  71          0       n/a       n/a       n/a     0.00%   100.00%    0.0000

*Correct Pixels represents the total number of independent validation pixels correctly identifed
in the error matrix.
The above accuracy assessment information is for agricultural land cover classes only. The accuracy of the non-agricultural land cover classes within the Cropland Data Layer is entirely dependent upon the USGS, National Land Cover Dataset (NLCD 2001). Thus, the USDA, NASS recommends that users consider the NLCD for studies involving non-agricultural land cover. For more information on the accuracy of the NLCD please reference <http://www.mrlc.gov/>.
Quantitative_Attribute_Accuracy_Assessment:
Attribute_Accuracy_Value:
Classification accuracy is generally 85% to 95% correct for the major crop-specific land cover categories. See the 'Attribute Accuracy Report' section of this metadata file for the detailed accuracy report.
Attribute_Accuracy_Explanation:
The strength and emphasis of the CDL is crop-specific land cover categories. The accuracy of the CDL non-agricultural land cover classes is entirely dependent upon the USGS, National Land Cover Dataset (NLCD 2001). Thus, the USDA, NASS recommends that users consider the NLCD for studies involving non-agricultural land cover.

The official DVD contains additional accuracy assessment information that is not available through the Geospatial Data Gateway in the form of an associated confidence layer. The following description of the confidence layer is taken from the document entitled 'MDA_NLCD_User_Guide.doc' which is available free for download with the NLCD Mapping Tool at <http://www.mrlc.gov/>. The Confidence Layer "spatially represents the predicted confidence that is associated with that output pixel, based upon the rule(s) that were used to classify it. This is useful in that the user can see the spatial representation of distribution and magnitude of error or confidence for a given classification... This error layer represents a percent confidence associated with each rule and output categorical, classified value. It is expressed as a percentage of confidence. A value of zero would therefore have a low confidence (always wrong), while a value of 100 would have a very high confidence (always right)." For more information on the use of confidence layers please refer to the following paper: Liu, Weiguo, Sucharita Gopal and Curtis E. Woodcock, 2004. Uncertainty and confidence in land cover classification using a hybrid classifier approach, Photogrammetric Engineering & Remote Sensing, 70(8):963-971. Ultimately, however, the confidence value is not a measure of accuracy for a given pixel but rather a how well it fit within the decision tree ruleset.

These definitions of accuracy statistics were derived from the following book: Congalton, Russell G. and Kass Green. Assessing the Accuracy of Remotely Sensed Data: Principles and Practices. Boca Raton, Florida: CRC Press, Inc. 1999. The 'Producer's Accuracy' is calculated for each cover type in the ground truth and indicates the probability that a ground truth pixel will be correctly mapped (across all cover types) and measures 'errors of omission'. An 'Omission Error' occurs when a pixel is excluded from the category to which it belongs in the validation dataset. The 'User's Accuracy' indicates the probability that a pixel from the CDL classification actually matches the ground truth data and measures 'errors of commission'. The 'Commission Error' represent when a pixel is included in an incorrect category according to the validation data. It is important to take into consideration errors of omission and commission. For example, if you classify every pixel in a scene to 'wheat', then you have 100% Producer's Accuracy for the wheat category and 0% Omission Error. However, you would also have a very high error of commission as all other crop types would be included in the incorrect category. The 'Kappa' is a measure of agreement based on the difference between the actual agreement in the error matrix (i.e., the agreement between the remotely sensed classification and the reference data as indicated by the major diagonal) and the chance agreement which is indicated by the row and column totals. The 'Conditional Kappa Coefficient' is the agreement for an individual category within the entire error matrix.
Logical_Consistency_Report:
The Cropland Data Layer (CDL) has been produced using training and independent validation data from the Farm Service Agency (FSA) Common Land Unit (CLU) Program (agricultural data) and United States Geological Survey (USGS) National Land Cover Dataset 2001 (NLCD 2001). More information about the FSA CLU Program can be found at <http://www.fsa.usda.gov/>. More information about the NLCD 2001 can be found at <http://www.mrlc.gov/>. The CDL encompasses the entire state unless noted otherwise in the 'Completeness Report' section of this metadata file.
Completeness_Report: The entire state is covered by the Cropland Data Layer.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The AWiFS satellite imagery is purchased in an orthorectified and projected format. The Cropland Data Layer retains the spatial attributes of the input AWiFS imagery.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value: 60 meter CE90
Horizontal_Positional_Accuracy_Explanation:
The AWiFS imagery used in the production of the Cropland Data Layer is purchased with an orthorectified level of processing. Thus, the CDL will retain the input imagery's positional accuracy of 60 meters at the circular error at the 90 percent confidence level (CE90). CE90 is a standard metric often used for horizontal accuracy in map products and can be interpreted as 90% of well-defined points tested must fall within a certain radial distance.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator:
Indian Remote-Sensing Satellite series of ISRO (Indian Space Research Organization)
Title: RESOURCESAT-1 (IRS-P6) Advanced Wide Field Sensor (AWiFS)
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publisher: GeoEye
Publication_Place: Dulles, Virginia 20166
Publication_Date: 2007 growing season
Other_Citation_Details:
The RESOURCESAT-1 (IRS-P6) AWiFS satellite sensor operates in four spectral bands at a spatial resolution of 56 meters. Additional information about AWiFS data can be obtained at <http://www.isro.org/programmes.htm>. The AWiFS imagery used in the Cropland Data Layer is obtained through a partnership with the USDA, Foreign Agricultural Service, International Production Assessment (IPA) Program. Acquisition begins April 1 and ends September 30 of the current growing season. Refer to the 'Supplemental Information' Section of this metadata file for specific scene date, path, row and quadrants used as classification inputs.
Source_Scale_Denominator: 56 meter
Type_of_Source_Media: CD-ROM and/or DVD
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20070401
Ending_Date: 20070930
Source_Currentness_Reference: ground condition
Source_Contribution: Raw data used in land cover spectral signature analysis
Source_Information:
Source_Citation:
Citation_Information:
Originator:
United States Geological Survey (USGS) and National Aeronautics and Space Administration (NASA) Land Processes Distributed Active Archive Center (LP DAAC)
Title:
Moderate Resolution Imaging Spectroradiometer (MODIS), 250 meter resolution 16-day composite Normalized Difference Vegetation Index (NDVI) from the Terra satellite (MOD13Q1v4)
Geospatial_Data_Presentation_Form: vegetation indices based on remote-sensing imagery
Publication_Information:
Publisher: USGS Center for Earth Resources Observation and Sciences (EROS)
Publication_Place: Sioux Falls, South Dakota 57198 USA
Publication_Date:
late 2006 growing season (used to improve winter wheat identification) and the entire 2007 growing season
Other_Citation_Details:
The Moderate Resolution Imaging Spectroradiometer (MODIS), 250 meter resolution 16-day composite Normalized Difference Vegetation Index (NDVI) data products from the Terra satellite (MOD13Q1v4) are downloaded from <http://edcdaac.usgs.gov/modis/dataproducts.asp>. Often late-season MODIS NDVI data are used from the previous growing season in an effort to improve winter wheat detection. Refer to the 'Supplemental Information' Section of this metadata file for specific dates used as classification inputs.
Source_Scale_Denominator: 250 meter
Type_of_Source_Media: online download
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20061001
Ending_Date: 20070930
Source_Currentness_Reference: ground condition
Source_Contribution: NDVI data used in land cover spectral signature analysis
Source_Information:
Source_Citation:
Citation_Information:
Originator:
United States Geological Survey (USGS) Earth Resources Observation and Science (EROS) Data Center
Title: The National Elevation Dataset (NED)
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publisher: USGS, EROS Data Center
Publication_Place: Sioux Falls, South Dakota 57198 USA
Publication_Date: Continuously updated
Other_Citation_Details:
The USGS NED Digital Elevation Model (DEM) is used as an ancillary data source in the production of the Cropland Data Layer. Slope and Aspect derived from the DEM are also used as additional classification inputs. More information on the USGS NED can be found at <http://ned.usgs.gov/>. Refer to the 'Supplemental Information' Section of this metadata file for the complete list of ancillary data sources used as classification inputs.
Source_Scale_Denominator: 30 meter
Type_of_Source_Media: online
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: unknown
Source_Currentness_Reference: ground condition
Source_Contribution:
spatial and attribute information used in land cover spectral signature analysis
Source_Information:
Source_Citation:
Citation_Information:
Originator:
United States Geological Survey (USGS) Earth Resources Observation and Science (EROS) Data Center
Title: National Land Cover Database 2001 (NLCD 2001)
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publisher: USGS, EROS Data Center
Publication_Place: Sioux Falls, South Dakota 57198 USA
Publication_Date: 2006
Other_Citation_Details:
The NLCD 2001 was used as ground training and validation for non-agricultural categories. Additionally, the USGS NLCD 2001 Imperviousness and Tree Canopy layers were used as ancillary data sources in the Cropland Data Layer classification process. More information on the NLCD 2001 can be found at <http://www.mrlc.gov/>. Refer to the 'Supplemental Information' Section of this metadata file for the complete list of ancillary data sources used as classification inputs.
Source_Scale_Denominator: 30 meter
Type_of_Source_Media: online
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: unknown
Source_Currentness_Reference: ground condition
Source_Contribution:
spatial and attribute information used in the spectral signature training and validation of non-agricultural land cover
Source_Information:
Source_Citation:
Citation_Information:
Originator:
United States Department of Agriculture (USDA), Farm Service Agency (FSA)
Title: USDA, FSA Common Land Unit (CLU)
Geospatial_Data_Presentation_Form: vector digital data
Publication_Information:
Publisher: USDA, FSA Aerial Photography Field Office

Publication_Place: Salt Lake City, Utah 84119-2020 USA
Publication_Date: 2006
Other_Citation_Details:
Access to the USDA, Farm Service Agency (FSA) Common Land Unit (CLU) digital data set is currently limited to FSA and Agency partnerships. During the current growing season, producers enrolled in FSA programs report their growing intentions, crops and acreage to USDA Field Service Centers. Their field boundaries are digitized in a standardized GIS data layer and the associated attribute information is maintained in a database known as 578 Administrative Data. This CLU/578 dataset provides a comprehensive and robust agricultural training and validation data set for the Cropland Data Layer. Additional information about the CLU Program can be found at <http://www.fsa.usda.gov/>.
Source_Scale_Denominator: 1:4800
Type_of_Source_Media: online
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: unknown
Source_Currentness_Reference: ground condition, updated annually
Source_Contribution:
spatial and attribute information used in the spectral signature training and validation of agricultural land cover
Process_Step:
Process_Description:
OVERVIEW: The United States Department of Agriculture (USDA), National Agricultural Statistics Service (NASS) Cropland Data Layer (CDL) Program is a unique agricultural-specific land cover geospatial product that is reproduced annually in participating states. The CDL Program builds upon NASS' traditional crop acreage estimation program and integrates Farm Service Agency (FSA) grower-reported field data with satellite imagery to create an unbiased statistical estimator of crop area at the state and county level for internal use. It is important to note that the internal acreage estimates produced using the CDL are not simple pixel counting. It is more of an 'Adjusted Census by Satellite.'

SOFTWARE: Leica Geosystems ERDAS Imagine is used in the pre- and post- processing of all raster-based data. ESRI ArcGIS is used to prepare the vector-based training and validation data. Rulequest See5.0 is used to create a decision tree based classifier. The NLCD Mapping Tool is used to apply the See5.0 decision-tree via ERDAS Imagine.

DECISION TREE CLASSIFIER: This Cropland Data Layer used the decision tree classifier approach. Using a decision tree classifier is a departure from older versions of the CDL which were created using in-house software (Peditor) based upon a maximum likelihood classifier approach. Check the 'Process Description' section of the specific state and year metadata file to verify the methodology used. Decision trees offer several advantages over the more traditional maximum likelihood classification method. The advantages include being: 1) non-parametric by nature and thus not reliant on the assumption of the input data being normally distributed, 2) efficient to construct and thus capable of handling large and complex data sets, 3) able to incorporate missing and non-continuous data, and 4) able to sort out non-linear relationships.

GROUND TRUTH: As with the maximum likelihood method, decision tree analysis is a supervised classification technique. Thus, it relies on having a sample of known ground truth areas in which to train the classifier. Older versions of the CDL (prior to 2006) utilized ground truth data from the annual June Agricultural Survey (JAS). Beginning in 2006, the CDL utilizes the very comprehensive ground truth data provided from the FSA Common Land Unit (CLU) Program as a replacement for the JAS data. The FSA CLU data have the advantage of natively being in a GIS and containing magnitudes more of field level information. Disadvantages include that it is not truly a probability sample of land cover and has bias toward subsidized program crops. Additional information about the FSA data can be found at <http://www.fsa.usda.gov/>.

INPUTS: The CDL is produced using satellite imagery from the Indian Remote Sensing RESOURCESAT-1 (IRS-P6) Advanced Wide Field Sensor (AWiFS) collected during the current growing season. NASS acquires AWiFS imagery for CDL production states from April 1 through September 30 of the current growing season through a cooperative agreement with the USDA, Foreign Agricultural Service (FAS), International Production Assessment (IPA) unit. Ancillary inputs include; the United States Geological Survey (USGS) National Elevation Dataset (NED), the USGS National Land Cover Dataset 2001 (NLCD 2001), and the National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) 250 meter 16 day Normalized Difference Vegetation Index (NDVI) composites.

ACCURACY: The accuracy of the land cover classifications are evaluated using independent validations data sets generated from the FSA CLU data (agricultural categories) and the NLCD 2001 (non-agricultural categories). The Producer's Accuracy is generally 85% to 95% correct for the major crop-specific land cover categories. See the 'Attribute Accuracy Report' section of this metadata file for the full accuracy report. The official DVD contains additional accuracy assessment information that is not available through the Geospatial Data Gateway in the form of an associated confidence layer. See the 'Attribute Accuracy Explanation' Section of this metadata file for more information on the confidence layer.

PUBLIC RELEASE: The USDA, NASS Cropland Data Layer is considered public domain and free to redistribute. The data is available on DVD for the cost of reproduction through the official website at <http://www.nass.usda.gov/research/Cropland/SARS1a.htm>. The data is also available free for download through the Geospatial Data Gateway at <http://datagateway.nrcs.usda.gov/>. See the 'Ordering Instructions' section of this metadata file for detailed download instructions. Please note that in no case are farmer reported data revealed or derivable from the public use Cropland Data Layer.
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USDA, NASS, Spatial Analysis Research Section
Contact_Person: USDA, NASS, Spatial Analysis Research Section staff
Contact_Address:
Address_Type: mailing and physical address
Address: 3251 Old Lee Highway, Room 305
City: Fairfax
State_or_Province: Virginia
Postal_Code: 22030-1504
Country: USA
Contact_Voice_Telephone: 703-877-8000
Contact_Facsimile_Telephone: 703-877-8044
Contact_Electronic_Mail_Address: HQ_RD_GIB@nass.usda.gov
Cloud_Cover:
Generally, there is enough cloud-free AWiFS satellite imagery available during the growing season that there will be no cloud cover in the published CDL. Older versions of the CDL (prior to 2006) may contain significant cloud cover due to available imagery and processing limitations which have since been overcome. Reference the attribute information within the specific CDL state and year image file to verify the extent of cloud cover.
Spatial_Data_Organization_Information:
Indirect_Spatial_Reference: Iowa
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 6511
Column_Count: 9792
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name:
FOR GEOSPATIAL DATA GATEWAY USERS: Universal Transverse Mercator (UTM)

FOR CD-ROM AND/OR DVD USERS: Albers Conical Equal Area is the native projection used in the production of the Cropland Data Layer. Due to technical restrictions, the online data available free for download through the Geospatial Data Gateway can only be offered in UTM. However, the official Cropland Data Layer CD-Rom and/or DVD available at <http://www.nass.usda.gov/research/Cropland/SARS1a.htm> includes the data in its native Albers Conical Equal Area coordinate system, in addition to UTM. The projection parameters for the Albers projection are as follows: 
Map_Projection_Name: Albers Conical Equal Area
Albers_Conical_Equal_Area:
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_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 56
Ordinate_Resolution: 56
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257223563
Universal_Transverse_Mercator:
UTM_Zone_Number: 15 North
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: -93
Latitude_of_Projection_Origin: 0
False_Easting: 500000
False_Northing: 0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 56
Ordinate_Resolution: 56
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: WGS84
Ellipsoid_Name: WGS84
Semi-major_Axis: 6378137.00

Denominator_of_Flattening_Ratio: 298.257223563
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
The Cropland Data Layer (CDL) is produced using agricultural training data from the Farm Service Agency (FSA) Common Land Unit (CLU) Program and non-agricultural training data from the United States Geological Survey (USGS) National Land Cover Dataset 2001 (NLCD 2001). The strength and emphasis of the CDL is crop-specific land cover categories. The accuracy of the CDL non-agricultural land cover classes are entirely dependent upon the NLCD. Thus, the USDA, NASS recommends that users consider the NLCD for studies involving non-agricultural land cover.
Entity_and_Attribute_Detail_Citation:
If the following table does not display properly, then please visit this internet site <http://www.nass.usda.gov/research/Cropland/metadata/meta.htm> to view the original metadata file. 
 Data Dictionary: USDA, National Agricultural Statistics Service, 2007 Iowa Cropland Data Layer

 Source: USDA, National Agricultural Statistics Service

 The following is a cross reference list of the categorization codes and
 land covers. Note that not all land cover categories listed below will
 appear in an individual state.

 Raster
 Attribute Domain Values and Definitions: ROW CROPS 1-20

 Categorization Code   Land Cover
         "1"           Corn
         "2"           Cotton
         "3"           Rice
         "4"           Sorghum
         "5"           Soybeans
         "6"           Sunflowers
         "10"          Peanuts
         "11"          Tobacco

 Raster
 Attribute Domain Values and Definitions: GRAINS,HAY,SEEDS 21-40

 Categorization Code   Land Cover
         "21"          Barley
         "22"          Durum Wheat
         "23"          Spring Wheat
         "24"          Winter Wheat
         "25"          Other Small Grains
         "26"          Winter Wheat/Soybeans Double-Cropped
         "27"          Rye
         "28"          Oats
         "29"          Millet
         "30"          Speltz
         "31"          Canola
         "32"          Flaxseed
         "33"          Safflower
         "34"          Rape seed
         "35"          Mustard
         "36"          Alfalfa
         "37"          Other Hays

 Raster
 Attribute Domain Values and Definitions: OTHER CROPS 41-60

 Categorization Code   Land Cover
         "41"          Sugarbeets
         "42"          Dry Beans
         "43"          Potatoes
         "44"          Other Crops
         "45"          Sugarcane
         "46"          Sweet Potatoes
         "47"          Miscellaneous Vegetables & Fruit
         "48"          Watermelon
         "50"          Pickles
         "51"          Chick Peas
         "52"          Lentils
         "53"          Peas
         "58"          Clover/Wildflowers

 Raster
 Attribute Domain Values and Definitions: OPEN NON-CROP 61-65

 Categorization Code   Land Cover
         "61"          Fallow/Idle Cropland
         "62"          Grass/Pasture/Non-agricultural
         "63"          Woodland
         "64"          Shrubland
         "65"          Barren

 Raster
 Attribute Domain Values and Definitions: TREE CROPS 66-80

 Categorization Code   Land Cover
         "67"          Peaches
         "68"          Apples
         "69"          Grapes
         "70"          Christmas Trees
         "71"          Other Tree Nuts & Fruit
         "72"          Citrus
         "73"          Other Tree Fruit
         "80"          Other Non-Tree Fruit

 Raster
 Attribute Domain Values and Definitions: OTHER NON-CROP 81-99

 Categorization Code   Land Cover
         "81"          Clouds
         "82"          Urban/Developed
         "83"          Water
         "87"          Wetlands
         "92"          Aquaculture

 Raster
 Attribute Domain Values and Definitions: NLCD-DERIVED NON-CROP 100-195

 Categorization Code   Land Cover
         "111"          NLCD - Open Water
         "112"          NLCD - Perennial Ice, Snow
         "121"          NLCD - Developed/Open Space
         "122"          NLCD - Developed/Low Intensity
         "123"          NLCD - Developed/Medium Intensity
         "124"          NLCD - Developed/High Intensity
         "131"          NLCD - Barren
         "141"          NLCD - Deciduous Forest
         "142"          NLCD - Evergreen Forest
         "143"          NLCD - Mixed Forest
         "152"          NLCD - Shrubland
         "171"          NLCD - Grassland Herbaceous
         "181"          NLCD - Pasture/Hay
         "182"          NLCD - Cultivated Crop
         "190"          NLCD - Woody Wetlands
         "195"          NLCD - Herbaceous Wetlands
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USDA, NASS Customer Service
Contact_Person: USDA, NASS Customer Service Staff
Contact_Address:
Address_Type: mailing and physical address
Address: 1400 Independence Avenue, SW, Room 5038-S
City: Washington
State_or_Province: District of Columbia
Postal_Code: 20250-9410
Country: USA
Contact_Voice_Telephone: 800-727-9540
Contact_Facsimile_Telephone: 703-877-8044
Contact_Electronic_Mail_Address: HQ_RD_OD@nass.usda.gov
Contact_Instructions:
The Cropland Data Layer is available free for download at <http://datagateway.nrcs.usda.gov/>.
To order a CD-ROM or DVD fill out the order form at <http://www.nass.usda.gov/research/Cropland/SARS1a.htm> and submit it either electronically (invoice will follow with the delivery) or mail the completed form with your check to: USDA/NASS Customer Service, 1400 Independence Avenue, SW, Room 5829-S, Washington DC 20250-9410. Please note 'Cropland Data Layer - (State and Year)' in the 'Memo' of your check. Checks should be made out to 'USDA, NASS'. Allow 1 week for delivery.
Resource_Description: Cropland Data Layer - Iowa 2007
Distribution_Liability:
Disclaimer: Users of the Cropland Data Layer (CDL) are solely responsible for interpretations made from these products. The CDL is provided 'as is' and the USDA, NASS does not warrant results you may obtain using the Cropland Data Layer. Contact our staff at (HQ_RD_OD@nass.usda.gov) if technical questions arise in the use of the CDL. NASS does maintain a Frequently Asked Questions (FAQ's) section on the CDL website at <http://www.nass.usda.gov/research/Cropland/SARS1a.htm>.

Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: GEOTIFF
Format_Version_Date: Iowa 2007
Format_Information_Content: GEOTIFF
Transfer_Size:
The image file size will vary depending on the state and completeness of coverage. The CD-ROM and/or DVD obtained through the official website <http://www.nass.usda.gov/research/Cropland/SARS1a.htm> contains data for a single year.
When downloading the data through the Geospatial Data Gateway <http://datagateway.nrcs.usda.gov/> all available years of CDL production for the requested state are included in one compressed file. Technical restrictions do not allow us to offer the CDL by individual state/year through the Geospatial Data Gateway. See the 'Ordering Instructions' section of this metadata file for additional information.
Digital_Transfer_Option:
Offline_Option:
Offline_Media: CD-ROM or DVD
Recording_Format: DOS-COPY
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <http://datagateway.nrcs.usda.gov/>
Access_Instructions:
See the 'Ordering Instructions' section of this metadata file for detailed download instructions.
Fees:
The USDA, NASS charges a nominal fee to cover the cost of CD-ROM and DVD production and shipping costs. Please visit the official website <http://www.nass.usda.gov/research/Cropland/SARS1a.htm> for prices. Distribution issues can also be directed to the NASS Customer Service Hotline at 1-800-727-9540. The Cropland Data Layer is also available free for download at <http://datagateway.nrcs.usda.gov/>.
Ordering_Instructions:
To order a CD-ROM or DVD fill out the order form at <http://www.nass.usda.gov/research/Cropland/SARS1a.htm> and submit it either electronically (invoice will follow with the delivery) or mail the completed form with your check to: USDA, NASS Customer Service, 1400 Independence Avenue, SW, Room 5829-S, Washington DC 20250-9410. Please note 'Cropland Data Layer - (State and Year)' in the 'Memo' part of your check. Checks should be made out to 'USDA, NASS'. Allow 1 week for delivery. Distribution issues can also be directed to the NASS Customer Service Hotline at 1-800-727-9540.

The Cropland Data Layer is also available free for download from the NRCS Geospatial Data Gateway at <http://datagateway.nrcs.usda.gov/>.

IMPORTANT NOTE: When downloading the CDL using the NRCS Geospatial Data Gateway all available years of CDL production for the requested state are included in a single compressed file. Geospatial Data Gateway technical restrictions do not allow us to offer the CDL by individual state/year. We are working on offering this option in the future. 
Instructions for downloading from the NRCS Geospatial Data Gateway:

Start by clicking on 'Get Data'

Then click on 'Quick State'

Scroll down to choose your state and click 'Continue'

Choose 'Land_use_land_cover' and select 'Cropland Data Layer by State' and 'Continue to Step3'

Choose 'Continue' to Step4

Lastly, you are given the option to download the data for free or to order the
official DVD/CD for the cost of the reproduction.
Turnaround: Allow 1 week for delivery for CD-ROM and/or DVD.
Custom_Order_Process:
For a list of other states and years of available data please visit: <http://www.nass.usda.gov/research/Cropland/SARS1a.htm>. Distribution issues can also be directed to the NASS Customer Service Hotline at 1-800-727-9540. The Cropland Data Layer is also available free for download at <http://datagateway.nrcs.usda.gov/>.
Technical_Prerequisites:
If the user does not have software capable of viewing GEOTIF (.tif) or ERDAS Imagine (.img) file formats then we suggest using the freeware browser ESRI ArcReader <http://www.esri.com/arcreader/>.
Metadata_Reference_Information:
Metadata_Date: 20080306
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USDA, NASS, Spatial Analysis Research Section
Contact_Person: USDA, NASS, Spatial Analysis Research Section Staff
Contact_Address:
Address_Type: mailing and physical address
Address: 3251 Old Lee Highway, Room 305
City: Fairfax
State_or_Province: Virginia
Postal_Code: 22030-1504
Country: USA
Contact_Voice_Telephone: 703-877-8000
Contact_Facsimile_Telephone: 703-877-8044
Contact_Electronic_Mail_Address: HQ_RD_GIB@nass.usda.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Access_Constraints: No restrictions on the distribution or use of the metadata file
Metadata_Use_Constraints: No restrictions on the distribution or use of the metadata file
Generated by mp version 2.9.6 on Mon Mar 03 16:09:13 2008