SMEX03 Land Use Classification Data: Oklahoma

Summary

This data set consists of land use classification data derived from satellite imagery and of data obtained in the field as part of the Soil Moisture Experiment 2003 (SMEX03). Landsat 5 Thematic Mapper (TM) imagery of the Oklahoma, USA SMEX03 study area was retrieved for 10 July 2003 and classified using in situ data collected by sampling teams. High accuracy was achieved with respect to a test data set, and high qualitative accuracy was achieved when comparing the land cover to classification for the Southern Great Plains Experiments of 1997 and 1999, both of which took place in the same region. The land use classification image provides information about vegetation present in the study area at a resolution of 30 meters. Also included is a Microsoft Excel file listing the initial surface conditions for two sampling sites in Oklahoma: Oklahoma South (OS) and Little Washita (LW). The volume of the data set is approximately 97 megabytes. Data are provided in a flat binary file, header file, and a spreadsheet file, and are available via FTP.

These data were collected as part of a validation study for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). AMSR-E is a mission instrument launched aboard NASA's Aqua Satellite on 04 May 2002. AMSR-E validation studies linked to SMEX are designed to evaluate the accuracy of AMSR-E soil moisture data. Specific validation objectives include assessing and refining soil moisture algorithm performance; verifying soil moisture estimation accuracy; investigating the effects of vegetation, surface temperature, topography, and soil texture on soil moisture accuracy; and determining the regions that are useful for AMSR-E soil moisture measurements.

Citing These Data

The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.

Jackson, T. J. and M. H. Cosh. 2009. SMEX03 Land Use Classification Data: Oklahoma. Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.

Overview Table

Category	Description
Data format	8-bit binary data file Excel spreadsheet file
Spatial coverage and resolution	Southernmost Latitude: 33.6° N Northernmost Latitude: 37.0° N Westernmost Longitude: 99.3° W Easternmost Longitude: 96.6° W Spatial resolution: 30 m
Temporal coverage and resolution	July 2003
Tools for accessing data	ArcView, ENVI, or other similar visualization software Any text editor or Web browser Any spreadsheet program
File naming convention	SMEX03_OK_Land_Cover.bil SMEX03_OK_Land_Cover.hdr Land_Cover.xls
File size	~97 MB
Parameter(s)	Land Use Classification
Procedures for obtaining data	Data are available via FTP.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigator(s)

Thomas J. Jackson
Hydrology/Remote Sensing Laboratory
US Department of Agriculture (USDA) - Agricultural Research Service (ARS)
Bldg. 007, Rm. 104, BARC-West
Beltsville, Maryland 20705 USA

Michael H. Cosh
Hydrology/Remote Sensing Laboratory
US Department of Agriculture (USDA) - Agricultural Research Service (ARS)
Bldg. 007, Rm. 104, BARC-West
Beltsville, MD 20705 USA

Acknowledgements

The investigators would like to acknowledge the USDA ARS Grazinglands Research Laboratory for their support as well as the many graduate students and volunteers who collected the field data.

Technical Contact

2. Detailed Data Description

Format

Land use classification data derived from Landsat 5 TM are provided in a flat, Band-Interleaved-by-Line binary file called SMEX03_OK_Land_Cover.bil. The Oklahoma study area image dimensions are 12,100 rows by 8201 columns. An Environment for Visualizing Images (ENVI) header file with geolocation information, called SMEX03_OK_Land_Cover.hdr, is also provided.

Additionally, in situ land cover classification data are provided in the Land_Cover.xls file. The file lists the initial surface conditions for each sampling site in the Oklahoma South and Little Washita regional study areas. Sampling sites are labeled by either OS (Oklahoma South) or LW (Little Washita) followed by the site number. For example, OS03 indicates the third sampling site in Oklahoma South study area. OS sampling site values range from 01-52. LW sampling site values include 02, 03, 04, 11, 12, 13, 20, 21, 22, 27, 28, 29, 31, 32, and 33. Also indicated in the Land_Cover.xls file is any noted change in surface condition, such as tillage, planting, or harvesting during the 2 - 18 July 2003 timeframe.

File and Directory Structure

All files are available on the FTP site in the following directory:

/soil_moisture/SMEX03/Oklahoma/ancillary_data/landuse_classification/

File Naming Convention

Landsat 5 TM data are provided in a single binary file with a corresponding header file. These files are named according to the following convention and are further described in Table 1:

SMEX03_OK_Land_Cover.bil
SMEX03_OK_Land_Cover.hdr
Land_Cover.xls

Where:

Table 1. Description of File Name Variables

Variable	Description
SMEX03	Soil Moisture Experiment 2003
OK	Oklahoma
Land_Cover	Parameter for this data set
.bil	Indicates that this is a Band-Interleaved-by-Line binary data file.
.hdr	Indicates that this is a header file.
.xls	Indicates that this is an Excel file.

File Size

The binary data file is approximately 97 MB, its header file is 1 KB, and the Excel file is 17 KB.

Spatial Coverage

Southernmost Latitude: 33.6° N
Northernmost Latitude: 37.0° N
Westernmost Longitude: 99.3° W
Easternmost Longitude: 96.6° W

Spatial Resolution

The pixel size is 30 m by 30 m.

Projection

Universal Transverse Mercator (UTM), Zone 14, World Geodetic System 1984 (WGS 84)

Temporal Coverage

TM imagery was collected for 10 July 2003. In situ data were collected from 2 through 18 July 2003.

Parameter or Variable

The measured parameter for this data set is land use (vegetation) classification. Land use classification distinguishes between crop types, water, roads, and urban areas.

Parameter Range

The parameter range for various Oklahoma land cover types is described in Table 2. Valid parameter range values range from 0 to 8.

Table 2. Parameter Range and Description

Parameter Value	Description
0	Unclassified
1	Forest
2	Pasture
3	Winter Wheat/Bare
4	Alfalfa
5	Corn
6	Urban/Quarry
7	Soybean
8	Water

 

Sample of Data Record

Figure 1 displays a partial sample of the SMEX03_OK_Land_Cover.bil image.

Figure 1. Land Use Classification Sample Data Record

 

Quality Assessment

Table 3 compares the accuracy of the in situ data with the accuracy of the image data obtained via satellite. The far right column lists the accuracy percentages of the in situ data when compared with the satellite image data. For example, of 581 classified forest pixels, only 566 of them are registered in the in situ data as forest, for a 97.4 percent accuracy. Accuracy percentages listed in the bottom row are the satellite image data compared to the in situ data. For example, of the 818 pixels that were deemed to be winter wheat in the field, only 665 of them were classified by Landsat 5 TM to be winter wheat, while 53 of them were classified as pasture and 100 were unclassified, for an accuracy of 81.3 percent.

Note: Urban/Quarry pixels were not subjected to ground truthing.

Table 3. Comparative Accuracy of In Situ Data Versus Image Data

In Situ Data
Landsat 5 TM Image Data		Forest	Pasture	Winter Wheat	Alfalfa	Corn	Soybean	Water	Total Pixels	Accuracy (%)
	Unclassified	2	-	100	-	2	1	2	107	N/A
	Forest	566	-	-	-	13	-	2	581	97.4
	Pasture	1	477	53	-	-	-	2	533	89.5
	Winter Wheat	-	-	665	-	-	-	-	665	100
	Alfalfa	-	21	-	58	-	-	-	79	73.4
	Corn	12	-	-	-	552	-	1	565	97.7
	Soybean	-	-	-	-	-	38	-	38	100
	Water	-	-	-	-	-	-	1259	1259	100
	Total Pixels	581	498	818	58	567	39	1266	3827	N/A
	Accuracy (%)	97.4	95.8	81.3	100	97.3	97.4	99.4	N/A	Overall Accuracy = 89 %

 

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The volume of this data set is approximately 97 MB.

Software and Tools

Tools appropriate for viewing these data include: ArcView, ENVI, or other similar visualization software packages; any text editor or Web browser; and any spreadsheet program.

Related Data Collections

• AMSR-E Validation Data: Soil Moisture Data Web site: Data sets from SMEX campaigns available at NSIDC.
• AMSR-E/Aqua Data at NSIDC Web site: AMSR-E standard products available at NSIDC.

4. Data Acquisition and Processing

Data Acquisition Methods

Oklahoma land use classification data were derived from both Landsat 5 TM imagery and in situ data, then classified and cross-verified for accuracy. These data were then compared to SGP97 and SGP99 land use classification data, two experiments which were conducted in the same region as SMEX03. Landsat 5 TM data were collected for 10 July 2003. Data were used from Path 28, Row 34-35 to cover the SMEX03 Oklahoma study area. In situ data were collected from 2 through 18 July 2003.

Processing Steps

One scene for 10 July 2003 was used to construct the land use classification for the SMEX03 Oklahoma study area. There was little cloud cover for this particular date and other dates in proximity to the experiment were of low quality.

1. In situ data were collected in and around Chickasha, El Reno, and the Little Washita Basin in Oklahoma, USA.
   
   
2. In situ data were converted to Regions of Interest (ROIs) within ENVI and one third of these data were set aside for verification purposes.
   
   
3. Landsat TM data for 10 July 2003 were collected and imported to ENVI for Path 28/Row 34-35.
   
   
4. Landsat TM images were masked for clouds. The pixels with values in band 1 (.45 - .52 um) greater than 110 were removed.
   
   
5. Shadowed areas in Band 4 ( .76 -.90um ) with values less than 50 were removed.
   
   
6. Bands 2,3,4,5,7 were extracted from 10 July 2003 and merged to create a 5 band image.
   
   
7. Within ENVI, a supervised maximum likelihood classification was conducted with a threshold of .85.
   
   
8. A classification image was available from SGP99. For areas that were masked due to clouds or shadows in the original classified image, SGP99 classifications were substituted, creating a merged image. Road network information was also superimposed on the image and those pixels selected as Urban/Quarry.
   
   
9. Accuracy percentages were calculated using a set of ROIs that were set aside for verification. Refer to Table 3 in the Quality Assessment section of this guide document for a listing of accuracy percentages.
   
   

5. References and Related Publications

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 70:829-840.


Table 4 lists publications related to this data set.

Table 4. Related Publications

Document	Description	URL
USDA SMEX03 Web Site	In-depth information on the science mission of the SMEX project	http://hydrolab.arsusda.gov/smex03/
The SGP99 Campaign Home Page	Information about the Southern Great Plains Experiment of 1999 (SGP99)	http://disc.sci.gsfc.nasa.gov/fieldexp/SGP99/
The Southern Great Plains '97 (SGP97) Data Archive Home Page	Information about the Southern Great Plains Experiment of 1997 (SGP97)	http://disc.sci.gsfc.nasa.gov/fieldexp/SGP97/

6. Document Information

Acronyms and Abbreviations

Table 5 lists the acronyms and abbreviations used in this document.

Table 5. Acronyms and Abbreviations

AMSR-E	Advanced Microwave Scanning Radiometer - Earth Observing System
ARS	Agricultural Research Service
BIL	Band-Interleaved-by-Line (.bil extension)
DAAC	Distributed Active Archive Center
ENVI	Environment for Visualizing Images
FTP	File Transfer Protocol
LW	Little Washita
N/A	Not Applicable
NASA	National Aeronautics and Space Administration
NSIDC	National Snow and Ice Data Center
OK	Oklahoma
ROI	Region of Interest
SGP99	Southern Great Plains Experiment 1999
SGP97	Southern Great Plains Experiment 1997
SMEX03	Soil Moisture Experiment 2003
TM	Thematic Mapper
URL	Uniform Resource Locator
WGS84	World Geodetic System 1984

Document Creation Date

January 2009

Document URL

http://nsidc.org/data/docs/daac/nsidc0365_smex03_landcover_ok/index.html