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| OverviewBackgroundDownload Sedclass Tool             Installation Program [MD5]Installation and User             GuideFolk Symbology Layers [MD5]Shepard Symbology         Layers [MD5]References | OVERVIEW
The U.S. Geological Survey (USGS) ArcMap Sediment       Classification tool is a custom toolbar that extends the Environmental       Systems Research Institute, Inc. (ESRI) ArcGIS 9.2 Desktop application to       aid in the analysis of seabed sediment classification.  The tool uses       as input either a point data layer with field attributes containing       percentage of gravel, sand, silt, and clay or four raster data layers       representing a percentage of sediment (0-100%) for the various sediment       grain size analysis: sand, gravel, silt and clay. This tool is designed to       analyze the percent of sediment at a given location and classify the       sediments according to either the Folk (1954, 1974) or Shepard (1954) as       modified by Schlee(1973) classification schemes.  The sediment       analysis tool is based upon the USGS**SEDCLASS** program (Poppe, et al. 2004).
UsageThe USGS ArcMap       Sediment Classification tool presented here is a custom toolbar to extend       the ArcGIS Desktop application to provide the **SEDCLASS** functionality within the ArcMap       application.  It has two uses: 1- to provide sediment classification       for previously unclassified point data that are available in a Feature or       standalone table; 2 – to produce a raster grid of the surficial sediment       distribution from four raster data layers representing percent gravel,       sand, silt and clay.  The logic for determining the sediment       classification is based upon the **SEDCLASS** program and allows the user to       select either the modified Folk or modified Shepard classification scheme.       System Requirements- ArcGIS V9.2 software installed on a computer         with Windows XP Operating System        
- Four raster data sets representing percent         sand, gravel, silt and clay for the area to be classified   *OR* 
- An ArcGIS feature or table data set containing         percent sediment having values between 0 to 100% 
Background Image showing sediment             classification for the Chesapeake Bay region.
A major component of the research conducted by the       U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole,       Science Center (WHSC) is seafloor mapping to map and characterize the sea       floor.  This work provides insight into the geologic makeup of the       seafloor and aids in research areas as diverse as habitat mapping,       location of geohazards and identifying areas of erosion and       deposition.  The geophysical tools including, seismic-reflection,       sidescan-sonar and bathymetric systems used to remotely map the seafloor       provide information regarding the sea floor and subsurface to define the       surficial geology and geologic framework of a given region.

Ground-truth techniques, such as sediment grab and       core sampling, are an integral part of seafloor mapping activities, and       provide specific information from directly-sampled material that aid in       interpretating the geophysics.  Sediment samples are analyzed within       the WHSC sediment laboratory for mean grain size, percent content of       gravel, sand, silt, clay, and mud, and additional analysis as required by       a given research project.  After completing the various analytic       processes, the sample data, with percent content of clay, silt, sand and       gravel are processed using the program **SEDCLASS** (Poppe, et al, 2003).

The **SEDCLASS**       program developed at the WHSC is used to classify sediment grain-size       distributions based on relationships between size fractions.  The       user may chose from either the Shepard (1954), as modified by Schlee       (1973), or Folk (1954, 1974) classification schemes.  The program       analyzes a comma delimited text file and must contain seven fields:       sample-identifier, latitude, longitude, and the percentages of gravel,       sand, silt, and clay in that specific order.  The output of the       program is also a comma delimited text file similar to the input with the       additional of an eight field containing the calculated sediment       classification based upon the system selected by the user.

The sample data, with sediment classification       information, output from program **SEDCLASS** is then converted to a Geographic       Information System (GIS) point data layer.  This allows the sample       points to be combined with other project data in a GIS mapview allowing       the samples to be co-located over the geophysical data (such as a sidescan       sonar mosaic).  This data integration aids the researchers in the       interpretation of the surficial geology.
Point Data Classification
This option allows a user to add the modified from       Folk or Shepard as modified by Schlee(1973) classification scheme to       previously unclassified sample data.  It is intended to provide a way       to classify sediment sample information that may have been analyzed       outside of the Woods Hole Science Center and does not contain the desired       classification information.  The input data must contain four fields       representing the percent gravel, sand, silt and clay.  Those       individual values together must total between 99 and 101% allowing for       minor round-up and round-down of the total sum.  A total percentage       of sediment outside of the range between 99 and 101 will not be assigned a       sediment classification and will be given a value of zero and no text       description.  A value of 0 is also assigned if any individual value       of gravel, sand, silt or clay in a record is less than zero.

For more detailed information regarding this       option, please see the section entitled Feature/Table Tutorial in the       PDFInstallation and Users       Guide.
Raster Classification
Having the classified sediment sample point       information is helpful when interpreting the surficial geology of an       area.  Processing those points to produce a surface of the survey       area may provide more insight into trends.  The Raster       Classification option allows the user to produce a surface raster modified       from Folk(1954, 1974) or Shepard, as modified by Schlee (1973), classified       sediment distribution.  Implementing this option of the sediment       classification toolbar is more involved and requires more prep work by the       user.

To begin, the user must locate sediment data that       contains, or that can be derived from, the four values of percent gravel,       sand, silt and clay.  Each of those individual values must be gridded       to produce a raster data layer representing the surface       distribution.  One way to produce a grid is through the use of the       ArcMap surface interpolation functions by interpolating point sample data.       Interpolation is the estimation of surface values at un-sampled points       based on known surface values of surrounding points. For further       discussion on interpolation and different interpolation techniques please       refer to the ArcGIS Desktop help system online at http://webhelp.esri.com/arcgisdesktop/9.2.      

The four raster layers of gravel, sand, silt and clay must have the same       spatial properties, i.e. cell size, extent, projection or an error message       will be generated and you will not be able to continue. The calculation of       the raster sediment type is accomplished using the four raster layers       of gravel, sand, silt, and clay and applying the formula in the appropriate       table of the "Installation and Users Guide" Appendix B to each raster on a       cell-by-cell basis. When the four raster data layers are complete, they       may be combined to create the output sediment classification raster.        The results of the raster classification for any given area will vary and       depend on the accuracy of the sample points, number of sample points,       distribution of the data points, gridded cell size and gridding method       employed by the user.

For more details on the installation and usage of       the USGS       ArcMap Sediment Classification tool, the user should refer to the PDFInstallation and Users       Guide.

ArcMap symbolization layers may be downloaded for       the Folk and Shepard classification.
References 
Folk, R.L., 1954, The distinction between grain      size and mineral composition in sedimentary rock nomenclature:Journal of      Geology, v. 62, no. 4, p. 344-359. 

Folk, R.L., 1974, The petrology of sedimentary      rocks: Austin, Tex., Hemphill Publishing Co., 182 p.

Poppe, L.J., Eliason, A.H., and Hastings, M.E.,      2003, A Visual Basic program to classify sediments based on      gravel-sand-silt-clay ratios: Computers and Geosciences, v. 29, no.6, p.      805-809.

Poppe, L.J., Williams, S.J., and Paskevich, V.F.,      2005, U.S. Geological Survey east-coast sediment snalysis;procedures,      database, and GIS data: U.S. Geological Survey Open-File Report      2005-1001.  Online at http://pubs.usgs.gov/of/2005/1001/

Reid, J.M., Reid, J.A., Jenkins, C.J., Hastings, M.E., Williams,S.J.,      and Poppe, L.J, 2005, usSEABED: Atlantic coast offshore surficialsediment      data release: U.S. Geological Survey Data Series 118, version 1.0.Online      at http://pubs.usgs.gov/ds/2005/118/

Schlee, J., 1973, Atlantic continental shelf and      slope of the United States -- sediment texture of the northeasternpart:      U.S. Geological Survey Professional Paper 529-L, 64 p.

Shepard, F.P., 1954, Nomenclature based on      sand-silt-clay ratios: Journal Sedimentary Petrology, v. 24, p.      151-158.   |
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U.S. Department of the Interior |		U.S. Geological Survey |		Coastal and Marine Geology		URL: cmgds.marine.usgs.gov/publications/of2007-1186/index.html		Page Contact Information: CMGDS Team		Page Last Modified: Wednesday, 06-Dec-2017 13:14:30 EST