This data set consists of land use classification data collected for the Iowa Soil Moisture Experiment 2002 (SMEX02) study region. The land use classification image provides information about vegetation present in the study area.
SMEX02 Land Surface Information: Land Use Classification, Version 1
This is the most recent version of these data.
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Geographic Coverage |
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Doraiswamy, P. C. and A. J. Stern. 2004. SMEX02 Land Surface Information: Land Use Classification, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/6IX22IHXNWBT. [Date Accessed].Detailed Data Description
Data are provided as one flat binary file, 3831 rows by 1851 columns with no header.
Land use classification data are located under the SMEX02 ancillary data directory on the FTP site, as shown in this image:
Data are in a single file named "classification.bil."
6.925 MB
Southernmost Latitude: 41.7° N
Northernmost Latitude: 42.04° N
Westernmost Longitude: 93.8° W
Easternmost Longitude: 93.2° W
Projection Description
Universal Transverse Mercator (UTM), Zone 15, Spheroid WGS84, Datum WGS84
Data were collected for three dates: 14 May, 1 July, and 17 July 2002.
Parameter Description
The parameters in this study are land use (vegetation) classifications. Land use classification distinguishes between crop types, water, roads, and urban areas. Pixels have a resolution of 30 m. The following table describes the values assigned to the vegetation and other elements in the land use classification file:
Value | Class |
---|---|
0 | Unclassified |
1 | Alfalfa |
2 | Corn |
3 | Grass |
4 | Soybean |
5 | Trees |
6 | Urban |
7 | Water |
10 | Overlaid roads |
Sample Image
A sample image from the data is shown below:
Software and Tools
Corn and soybean accuracies are good, but due to the large sample size of the corn and soybeans, accuracies in other land features are not as good. Small misclassifications in the soybean or corn areas can create larger inaccuracies in other classes. The following table shows the image readings and ground truth readings, and the accuracies calculated.
Image | Alfalfa | Corn | Grass | Soybean | Trees | Urban | Water | Total | Accuracy |
---|---|---|---|---|---|---|---|---|---|
Alfalfa | 66 | - | 3 | 20 | 1 | - | - | 90 | 73.33333333 |
Corn | 12 | 19291 | 209 | 379 | 17 | - | 10 | 19918 | 96.85209358 |
Grass | 50 | 97 | 472 | 93 | 104 | 4 | 46 | 866 | 54.5034642 |
Soybean | 136 | 66 | 63 | 14429 | 14 | 14 | 1 | 14723 | 98.00312436 |
Trees | 18 | 100 | 45 | 72 | 77 | - | 63 | 375 | 20.53333333 |
Urban | 3 | 2 | 7 | 20 | 1 | 2 | 0 | 35 | 5.714285714 |
Water | - | 7 | 5 | 1 | 6 | - | 56 | 75 | 74.66666667 |
Total | 285 | 19563 | 804 | 15014 | 220 | 20 | 176 | ||
Accuracy | 23.15789474 | 98.6096202 | 58.70646766 | 96.10364 | 35 | 10 | 31.81818 | 36082 | 95.319 |
Accuracies on the right in the chart are based on the image being the correct class for the ground truth. For example, of 90 classified alfalfa pixels, 66 of them are in the ground truth data for alfalfa, for 73 percent accuracy. The accuracy at the bottom of the chart is the ground truth compared to the image. For example, of the 285 pixels that were deemed to be alfalfa on the ground, only 66 of them were classified by Landsat Thematic Mapper (TM) to be alfalfa, while 136 of them were classified as soybean.
Data Acquisition and Processing
The land use classification data were derived from Landsat TM imagery and ground truth data. Landsat TM data were collected for three dates: 14 May, 1 July, and 17 July 2002. Data were used from Path 26, Row 30 and the southern portion of Path 26, Row 31, to cover the SMEX02 area. Ground truth data was collected on two separate trips in June and July 2002.
Processing Steps
The Landsat TM data was imported into ERDAS software for processing and classification. The land use classification image was registered to the road network provided by the Iowa Department of Transportation. The road network was converted into an image that showed each road as 60 meters wide. This image was embedded onto the classified image to remove the speckle along the roadways and to improve the image quality.
References and Related Publications
Contacts and Acknowledgments
Paul C. Doraiswamy
US Department of Agriculture (USDA) Hydrology and Remote Sensing Lab
Beltsville, MD
USA
Alan J. Stern
US Department of Agriculture (USDA) Hydrology and Remote Sensing Lab
Beltsville, MD
USA
The investigators thank the Soil Moisture Experiment 2002 Science Team, the National Soil Tilth Laboratory, the National Aeronautics and Space Administration (NASA), NASA Aqua AMSR Terrestrial Hydrology and Global Water Cycle Programs, and all those who collected and analyzed the data, including: Rogier Van der Velde, Ann Hsu, and Laura Kimes. They also want to thank the many graduate students and volunteers who collected field photographs.
Document Information
DOCUMENT CREATION DATE
November 2005