SMEX05 Land Use Classification Data: Iowa
Entry ID:
NSIDC-0446
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Summary
Abstract:
Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support for this data set may be limited. This data set contains land use classification data for the Walnut Creek watershed area of Ames, Iowa USA. Land cover classification was necessary for the modeling and ... scaling of hydrologic variables of concern in the Soil Moisture Experiment 2005 (SMEX05). For the Ames study region, the National Agricultural Statistical Service (NASS) Land Cover Estimate was used to represent land cover classes. High accuracy was achieved with respect to a test data set. The data were collected from 06 June 2005 through 17 July 2005. The total volume of the data set is approximately 28 megabytes. Data are provided in one Band Interleaved by Line (BIL) file with a corresponding Environment for Visualizing Images (ENVI) header file. Data are available via FTP. The Advanced Microwave Scanning Radiometer - Earth Observing System (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.
Related URL
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Description:
AMSR-E Validation Data
Description:
AMSR-E/Aqua Data
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Geographic Coverage
(Click for Interactive Map)
Spatial coordinates
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N: 42.07
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S: 41.87
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E: -93.52
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W: -94.02
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Temporal Coverage
Start Date:
2009-11-17
Stop Date:
2009-11-23
Quality
ATTRIBUTE ACCURACY REPORT: A team of field investigators participated in data verification exercises on December 9-13, 1996. Data validation teams consisted of personnel from the NOAA Coastal Services Center and Oak Ridge National Laboratory. Each team was equipped with a portable color laptop computer linked to a Global Positioning System (GPS). The field station runs ... software that supports the classified data as a raster background with the road network as a vector overlay with a simultaneous display of live GPS coordinates. Accuracy assessment points were generated with ERDAS Imagine software using a stratified random sample in 3x3 pixel homogeneous windows. To make the acquisition of the field reference data more practical, a twenty pixel buffer area around roads (i.e. 10 pixels on each side of the road) was created. 7,000 random points were generated within this area for the accuracy assessment. Collection of ground reference information for areas that have experienced a change in land cover type is a troublesome task. Pre-Processing Steps: The scene was georectified to UTM Zone 19 coordinates. Ancillary data sets: Subsequent field work and the use of collateral data such as USGS maps, county marsh inventories, and National Wetland Inventory data led to further refinements in the image classification. Shoreline features can be extracted from Landsat images by detecting the land/water interface. However, care must be used to avoid misinterpreting tidal differences as changes in shorelines, since the satellite images from which these land cover images are derived and acquired at different tidal stages, depending on when the satellite is overhead. The land cover classifications represent the instantaneous state of the shoreline at the moment of image acquisition. C-CAP data are mapped at 1:100,000 scale with 22 standard classes constituting major landscape components. They are not jurisdictional (can't be used for permitting) and will not identify individual species. However, they are useful for identifying regional landscape patterns, major functional niches, environmental impact assessment, urban planning, and zoning applications. If you need change analysis data at this scale, C-CAP may be your only option. C-CAP is designed around a 1 to 5 year revisit cycle. Land Cover is the complete human and natural landscape recorded as surface components - forest, water, wetlands, concrete, asphalt, etc. Land cover can be documented by analyzing spectral signatures of satellite and aerial imagery. Land Use is the documentation of human uses of the landscape - residential, commercial, agricultural, etc. Land use can be inferred but, not explicitly derived from satellite and aerial imagery. There is no spectral basis for land use determination in satellite imagery. C-CAP data can be used to identify concrete and asphalt as land cover, but we can only infer that these materials denote a residential or commercial use. Post-Processing Steps: The data were clipped to maine's southern state boundary and put through a datum conversion from NAD27 to UTM NAD83 zone 19. Known Problems: In addition, a very small portion of the June 1993 scene was obscured by numerous small cumulus clouds and shadows. The areas affected by clouds and shadows were mapped using an algorithm developed by ORNL. The corresponding areas were classified using an August 31, 1993 Landsat scene. Accuracy Results: This data set was found to be 86.4% accurate with a Kappa coefficient of 0.842. LOGICAL CONSISTENCY REPORT: Tests for logical consistency indicate that all row and column positions in the selected latitude/longitude window contain data. Conversion and integration with vector files indicates that all positions are consistent with earth coordinates covering the same area. Attribute files appear to be logically consistent. Examining the change matrix for logical fallacies, we find, for example, that a very small number of pixels changed from developed land to any other category. COMPLETENESS REPORT: The classification scheme comprehensively includes all anticipated land covers, and all pixels have been classified. The NOAA Coastal Change Analysis Program (C-CAP): Guidance for Regional Implementation, NOAA National Marine Fisheries Service Report 123, discusses the interagency effort to develop the land cover classification scheme and defines all categories. HORIZONTAL POSITIONAL ACCURACY REPORT: Precision corrected images were purchased from the EROS Data Center in UTM NAD27 meters to an RMSE +/- 0.5 pixels. VERTICAL POSITIONAL ACCURACY REPORT: There was no terrain correction in the georeferencing procedure. PROCESS DESCRIPTION: The processing steps for each C-CAP Southern Maine Land Cover Change Analysis 1986 - 1993 product are intricately associated. Each database is the result of many processing steps with numerous iterations for each step. The output of one processing step or database is often the input data for another processing step. A brief description of the processing steps used in the land cover classification of the this project follows. Further description of the processing steps can be found in the NOAA Coastal Change Analysis Program (C-CAP): Guidance for Regional Implementation, NOAA National Marine Fisheries Service Report 123 (Dobson et al, 1995). Baseline Classification Process: The Southern Maine land cover/change classification product was processed using an iterative classification approach. Landsat Thematic Mapper data for path/row/date(s): 12/30 19860609, 12/30 19930612, 12/30 19930831 were analyzed and mosaicked to create a land cover inventory for Southern Maine. Each scene was classified, focusing first on separating major categories (e.g. water, forest, marsh, herbaceous upland, and developed) using standard supervised classification techniques. Numerous individual areas were chosen as training sites for the land cover classification. The mean and covariance statistics for these areas are passed to an isodata classification algorithm which assigns an unknown pixel to the class in which it has the highest probability of being a member. Then iterative unsupervised classifications were performed on each major category individually by masking out all other major categories. With this type of unsupervised classification, the computer is allowed to query the multispectral properties of the masked scene using user specified criteria and to identify X mutually exclusive clusters in N-dimensional feature space. By masking out all data but a single major category, the spectral variance is greatly reduced thus decreasing classification errors. After several classification iterations of the masked data, final classification labels were assigned to the spectral clusters. Changes among major categories were permitted to occur even at this stage of processing. Subsequent field work and the use of collateral data such as USGS maps, TIGER road data, and National Wetland Inventory data led to further refinements in the image classification. In small areas where landcover class confusion could not be separated spectrally, human pattern recognition was used to recode the data. A spatial filter was applied to the final classification data file. Change Classification Process: Landsat Thematic Mapper data for path/row(s) 12/30 19860609, 12/30 19930612, 12/30 19930831 were analyzed to arrive at a land cover for Southern Maine. The change date land cover classification was in part derived from the baseline classification. Only the pixels in the June 12, 1993 image that changed spectrally from the change date image were classified for the June 9, 1986 data file. All other pixels were simply replaced with the baseline image classification. It is possible to simply identify the amount of change between two images by image differencing the same band in two images which have previously been rectified to a common basemap. Image differencing involves subtracting the imagery of one date from that of another. The subtraction results in positive and negative values in areas of radiance change and zero values in areas of no-change in a new 'change image'. The images are subtracted resulting in an signed 16-bit analysis with pixel values ranging from -255 to 255. The results were transformed into positive unsigned 16-bit values by adding a constant, c. The operation is expressed mathematically as: Dijk = BVijk(1) - BVijk(2) + c where Dijk = change pixel value BVijk(1) = brightness value at time 1 BVijk(2) = brightness value at time 2 c = a constant (e.g., 255). i = line number j = column number k = a single band (e.g. TM band 4). The 'change image' produced using image differencing usually yields a BV distribution approximately gaussian in nature, where pixels of no BV change are distributed around the mean and pixels of change are found in the tails of the distribution. A threshold value was carefully chosen to identify spectral 'change' and 'no-change' pixels in the 'change image.' A 'change/no-change' mask was derived by performing image differencing on band 4, and Normalized Difference Vegetation Index (NDVI) of the two date dataset and recoded into a binary mask file. The 'change/no-change' mask was then overlaid onto the earlier date of imagery and only those pixels which were detected as having spectrally changed were viewed as candidate pixels for categorical change. Change Detection Database The change date and baseline land cover classifications were compared on a pixel by pixel basis using a change detection matrix. This traditional post-classification comparison yields 'from land cover class - to land cover class' change information. Many pixels with sufficient change to be included in the mask of candidate pixels in the spectral change process did not qualify as categorical land cover change. This method may reduce change detection errors (omission and commission) and provides detailed 'from-to' change class information. The technique reduces effort by allowing analysts to focus on the small amount of area that has changed between dates. PROCESS DATE: 19960930 PROCESS DESCRIPTION: This data was projected to Universal Transverse Mercator zone 19 with a horizontal datum of NAD83. PROCESS DATE: Unknown SOURCE INFORMATION - CITATION: Earth Observation Satellite Company. Landsat Thematic Mapper Source_Geospatial_Data_Presentation_Form: remote-sensing image. 1986-06-09. OTHER CITATION DETAILS: Landsat Thematic Mapper scenes processed: Path = 12 Row = 30 Date 06-09-1986, 06-12-1993 and 08-31-1993 TYPE OF SOURCE MEDIA: 8 mm magnetic tape. SOURCE CURRENTNESS REFERENCE: ground condition. SOURCE CITATION ABBREVIATION: south_CH. SOURCE CONTRIBUTION: Source used in land cover classification. 
Access Constraints
ACCESS CONSTRAINTS: None, except for a possible fee at the cost of reproduction. DISTRIBUTION LIABILITY: Users must assume responsibility to determine the usability of these data.
Use Constraints
Data set is not for use in litigation. While efforts have been made to ensure that these data are accurate and reliable within the state of the art, NOAA, cannot assume liability for any damages, or misrepresentations, caused by any inaccuracies in the data, or as a result of the data to be used on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty. Additional Use Constraints: None
Data Set Progress
COMPLETE
Distribution
Distribution Media:
ONLINE
Distribution Format:
ERDAS Imagine (.img) format
Fees:
none
Personnel
Role:
DIF AUTHOR
Phone:
843-740-1200
Fax:
843-740-1224
Email:
csc at csc.noaa.gov
Contact Address:
NOAA Coastal Services Center
2234 South Hobson Avenue
City:
Charleston
Province or State:
SC
Postal Code:
29405-2413
Country:
USA
Creation and Review Dates
DIF Creation Date:
2001-07-06
Last DIF Revision Date:
2006-06-05
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