Digital Overlay for Soils of St. Landry Parish, Louisiana.

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Frequently-anticipated questions:


What does this data set describe?

    Title: Digital Overlay for Soils of St. Landry Parish, Louisiana.
    Abstract:
    This data set contains vector line map information. The vector data contain selected base categories of geographic features, and characteristics of these features, in digital form. The information was collected by digitizing and/or scanning soil information complied onto 7.5-minute quadrangle mylar sheets, creating an editable, digital soil coverage. The data set used 1:24000 scale hardcopy USGS standard quadrangle maps and the State Soil Survey of St. Landry Parish as a data development resource. The classified data was derived from actual field identification and sampling performed by the Natural Resource Conservation Service (NRCS), in Alexandria, Louisiana (formerly Soil Conservation Service). Digital data is available by Parish. The digital data is not Soil Survey Geographic database (SSURGO) certified.

  1. How should this data set be cited?

    United States Geological Survey, and Natural Resource Conservation S, 20020530, Digital Overlay for Soils of St. Landry Parish, Louisiana.: USGS BRD's National Wetlands Research Center, Lafayette, Louisiana, US.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -92.493
    East_Bounding_Coordinate: -91.679
    North_Bounding_Coordinate: 30.850
    South_Bounding_Coordinate: 30.299

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 26-Aug-1999
    Ending_Date: 29-May-2002
    Currentness_Reference: Publication date of sources

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Vector Digital Data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      Indirect_Spatial_Reference: The State of Louisiana
      This is a Vector data set.

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 15
      Transverse_Mercator:
      Longitude_of_Central_Meridian: -93
      Latitude_of_Projection_Origin: 0
      False_Easting: 500,000
      False_Northing: 0
      Scale_Factor_at_Central_Meridian: .9996

      Planar coordinates are encoded using Coordinate Pair
      Abscissae (x-coordinates) are specified to the nearest .61
      Ordinates (y-coordinates) are specified to the nearest .61
      Planar coordinates are specified in Meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257.

  7. How does the data set describe geographic features?

    Soils
    A natural, three-dimensional body at the earth's surface. It is capable of supporting plants and has properties resulting from the integrated effect of climate and living matter acting on earthy parent material, as conditioned by relief over periods of time. (Source: USDA, NRCS, and Soil Survey of St. Landry Parish.)

    soil_code
    Codes for soil units (Source: Soil Survey for St. Landry Parish, Louisiana: NRCS, in cooperation with Louisiana Agricultural Experiment Station and Louisiana Soil and Water Conservation Committee. Alexandria, Louisiana, USDA.)

    ValueDefinition
    AdB (Ac)Acadia Silt Loam, 1 to 3 Percent Slopes
    BdBaldwin Silty Clay Loam
    BhBladwin-Sharkey Complex, Gently Undulating
    BLBasile and Wrightsville Soils, Frequently Flooded
    BSA (new)Basile and Brule Soils, 0 to 3 Percent Slopes, Frequently Flooded
    CcCalhoun Silt Loam
    CdCommerce Silt Loam
    CECommerce and Convent Soils, Gently Undulating, Frequently Flooded
    CfConvent Very Fine Sandy Loam
    ChConvent Very Fine Sandy Loam, Gently Undulating
    CkConvent-Commerce Complex, Gently Undulating, Occasionally Flooded
    CoCoteau Silt Loam, 0 to 1 Percent Slopes
    CpCoteau Silt Loam, 1 to 3 Percent Slopes
    CwCrowley Silt Loam
    DeDundee Silt Loam
    DfDundee Silty Clay Loam
    DrDundee-Alligator Complex, Gently Undulating
    DsDundee-Sharkey Complex, Gently Undulating
    DuB (new)Duson Silt Loam
    FAFalaya Soils, Frequently Flooded
    FE (FC)Fausse and Sharkey Soils
    FoA (Fo)Frost Silt Loam
    FrA (Fr)Frost Silt Loam, Occasionally Flooded
    FzFrozard Silt Loam
    GaGallion Silt Loam
    GoGallion Silty Clay Loam
    GpGallion-Perry Complex, Gently Undulating
    IaIberia Clay
    JeA (Je)Jeanerette Silt Loam
    JuJudice Silty Clay Loam
    KvA (new)Kinder-Vidrine Silt Loams, 0 to 1 Percent Slopes
    LaLatanier Clay
    LbLebeau Clay
    LcLebeau Clay, Occasionally Flooded
    LeLoreauville Silt Loam
    LpLoring Silt Loam, 1 to 5 Percent Slopes
    LrLoring Silt Loam, 5 to 8 Percent Slopes
    MaB (Ma)Mamou Silt Loam, 1 to 3 Percent Slopes
    McMemphis Silt Loam, 0 to 1 Percent Slopes
    MbC (Md)Memphis Silt Loam, 1 to 5 Percent Slopes
    MeMemphis Silt Loam, 5 to 8 Percent Slopes
    MfMemphis Silt Loam, 8 to 20 Percent Slopes
    MtA (new)Mowata Silt Loam, 0 to 1 Percent Slopes
    MtMowata Silt Loam
    MUMuskogee-Loring Association, 8 to 20 Percent Slopes, Severely Eroded
    M-W (new)Miscellaneous Water
    PaA (Pa)Patoutville Silt Loam, 0 to 1 Percent Slopes
    PaB (Pb)Patoutville Silt Loam, 1 to 3 Percent Slopes
    PcA (new)Patoutville-Crowley Silt Loams, 0 to 1 Percent Slopes
    PcPatoutville-Crowley Complex
    PrPerry Clay, Frequently Flooded
    ShSharkey Clay
    SpSharkey Clay, Frequently Flooded
    SoSharkey Clay, Occasionally Flooded
    TsTensas-Sharkey Complex, Gently Undulating
    UD (new)Udorthents
    WvWrightsville-Vidrine Complex
    waterWater

    Entity_and_Attribute_Overview:
    The data set consists of vectored data for the 26 quadrangles in St. Landry Parish. Each polygon in the coverage has been assigned a corresponding soil code. The Parish's quadrangles can be found in the "Louisiana Index to topographic and other Map Coverage", published and distributed by the USGS, National Mapping Program. The description of soil codes can be found in the Soil Survey of St. Landry Parish.
    Entity_and_Attribute_Detail_Citation:
    Soil Survey of St. Landry Parish, published by the USDA, NRCS, and the Louisiana Index to topographic and other Map Coverage, Published and distributed by the USGS, National Mapping Program.


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    The NWRC acknowledges the NRCS for use of data derived from the SSURGO soils maps for St. Landry Parish, Louisiana.

  3. To whom should users address questions about the data?

    USGS BRD's National Wetlands Research Center
    c/o Steve Hartley
    Senior Geographer/GIS Analyst
    700 Cajundome Boulevard
    Lafayette, Louisiana 70506

    337-266-8543 (voice)
    337-266-8616 (FAX)
    steve_hartley@usgs.gov

    Hours_of_Service: 8:00 am to 4:00 pm CST Monday through Friday


Why was the data set created?

To provide digital overlays of the soils of Louisiana by parish for the NRCS, that can be updated and used as a layer in a GIS application.


How was the data set created?

  1. From what previous works were the data drawn?

    USDA Map (source 1 of 5)
    United States Department of Agr, in cooperation with the Louisiana , Unknown, Soil delineated aerial photography: USDA, NRCS, Alexandria, Louisiana.

    Type_of_Source_Media: Stable-based Material
    Source_Scale_Denominator: 24000
    Source_Contribution: Spatial and Attribute information for soil units.

    USDA, NRCS (source 2 of 5)
    USDA, NRCS, in cooperation with Louisiana A, 19780101, Soil Survey of St. Landry Parish, Louisiana: USDA, NRCS, Alexandria, Louisiana.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 20000
    Source_Contribution: Secondary attribute information for soil units.

    EOSAT (source 3 of 5)
    Earth Observation Satellite Company (EOSAT), 19930101, 1993 Landsat TM Imagery: EOSAT, Lanham, MD.

    Type_of_Source_Media: Digital Imagery
    Source_Contribution: Data for land cover/land use classification

    SPOT (source 4 of 5)
    Satellite Pour L'Observation de la Terre (SPOT), 19900101 - 19950101, SPOT Imagery: Satellite Pour L'Observation de la Terre (SPOT), Toulouse, France.

    Type_of_Source_Media: Digital Imagery
    Source_Contribution: Data for land cover/land use classification

    DOQQ (source 5 of 5)
    National Digital Orthophoto Program (NDOP)., 19981125, Digital Orthophoto Quarter Quadrangles (DOQQ): USDA, NRCS, and National Cartography and Geospatial Center., Fort Worth, Texas.

    Type_of_Source_Media: Digital Imagery
    Source_Contribution: Data for land cover/land use classification

  2. How were the data generated, processed, and modified?

    Date: 1998 (process 1 of 1)
    The following is a generalized description of the processes used in creating the parish soil digital coverages for Louisiana. Data for some parish soil maps may vary slightly. The data set was compiled by taking the original soil lines drawn over aerial photography by NRCS and transferring them to 7.5 minute quadrangle mylar sheets with a scale of 1:24,000 aided by the most accurate and available imagery. Soil lines for St. Landry Parish were initially compiled by the NRCS, excluding 3 quadrangles that were compiled at the NWRC over Spot/TM Imagery. The compiled soil lines for each quadrangle were then digitized and/or scanned individually. All quadrangles were then appended, cleaned, joined together and labeled to form the body of the parish coverage. On-screen land-water interfaces for every quadrangle were constructed, utilizing digital orthophoto quarter quadrangles (DOQQ's) after the soil lines were digital. On-screen and tablet digitizing was done using Production ARC/Edit, an adaptation of ESRI's ARC/Edit module. Scanning was performed on the IDEAL, FSC 8010 Color Scanner utilizing CADImage_Scan+Feature version 1.0 software and I_Vector version 3.81 for vectorization. The ARC/EDIT module was used for coverage generation with geospatial data, building, cleaning, and joining coverages. Polygons were assigned attributes, as labels, in ARCVIEW. The information is stored both as an ARC/INFO coverage and an exported .e00 compression file.

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The accuracy is not based on a formal quantitative assessment and was based on the judgement of the soil conservationist in the field. Ground truthing was not performed for this project. To attain a better estimate of accuracy, a formal re-evaluation of the soils of St. Landry Parish, Louisiana would be necessary to see if there are areas where discrepancies exist.

  2. How accurate are the geographic locations?

    Not applicable

  3. How accurate are the heights or depths?

    Not applicable

  4. Where are the gaps in the data? What is missing?

    All data sets were derived in the same general format. All soil information was transferred onto transparent mylar sheets, for each topographic quadrangle in the parish, from the existing State Soils Survey for the parish. Mylar overlays were digitized (entered at an error of less than .005 for geographic positioning) and/or scanned then rectified. Each quadrangle mylar overlay was digitized and/or scanned separately and therefore may represent different amounts of human and/or equipment error. Parish coverage quadrangles land-water interfaces were corrected by best judgement on-screen digitizing to Digital Orthophoto Quarter Quadrangles (DOQQ's), if available. For parishes created before DOQQ's were available, the land-water interfaces were included on the mylar sheets. For parishes created after DOQQ's became available, the land-water interfaces were digitized on-screen separately from the soil lines; therefore they are not included on the mylar sheets. The land-water coverages and soil line coverages were then appended and cleaned to create the total quadrangle coverage. Each quadrangle was edited individually, and then all quadrangles in the parish were joined together. Once joined together, editing was done along all quadrangle boundaries to match lines and labels. When line or label errors were found, all corrections were made upon approval of the NRCS. Problems with labeling occurred along adjoining parish boundaries, due to different labeling conventions in each parish. A standard labeling convention system for the whole state of Louisiana must be created to remedy the problem. Until this standard is developed, the following labeling tactics have been used. New labels were created for parish coverages in order to match labels for adjoining parishes. Changes were dependent upon soil definition, polygon size, and cases of duplication problems. A duplication problem means the label already existed in the parish coverage and is a different unit altogether and therefore can not be added to that legend. New labels were also created when new lines were needed to reduce confusion. Lines were added in special cases: 1) if it was advantageous to extend an unit a small portion into the next parish, rather than renaming the whole polygon; and 2) if the two units adjoining are similar, differing only in transitional phase, then a line was added at the most logical area of transition, aided by imagery, in order to keep the two units separate. New labels were created in the coverages which the line was added as long as there was not duplication problems. If major complications occurred when trying to add labels, these areas were left as is, waiting for a standard soil convention. These problems can be fixed after a standard Louisiana State soil code convention is established. The attribute legend for St. Landry Parish is found in the Entity and Attribute Section. This includes current modifications for completeness with surrounding parishes. All changes to the St. Landry Parish soil lines and legend are documented in a report to be stored with the state soils archives at the NRCS in Alexandria, LA. Modifications to the St. Landry Parish include the following: The following soil codes changed to match Acadia; Ac to AdB, Fo to FoA, Fr to FrA, Je to JeA, Ma to MaB, Md to MbC, Pa to PaA, Pb to PaB; Added new soil codes BSA, DuB, KvA, MtA, PcA from Acadia; Added UD (Levee), a new addition requested by Louisiana's State Soil Scientist as an update; Changed soil code FC to FE, across many parishes; Added M-W (Miscellaneous water) replacing, for example, sewage ponds.

  5. How consistent are the relationships among the observations, including topology?

    All polygons are closed, and have been cleaned in an editing environment. Adjacent polygons do not have identical attributes. Each polygon has one and only one attribute.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints:
It is strongly recommended that this data is directly acquired from the distributor described above or from another USGS Biological Resources Division server and not indirectly through other sources which may have changed the data in some way. The distributor makes no claims as to the data's suitability for other purposes.
Use_Constraints:
Acknowledgment of the NWRC as a data source would be appreciated in products developed from this data, and such acknowledgment as is standard for citation and legal practices for data source is expected by users of this data. Sharing new data layers developed directly from this data would also be appreciated by NWRC staff. Users should be aware that comparisons with other data sets for the same area from other time periods might be inaccurate due to inconsistencies resulting from changes in photo interpretation, mapping conventions, and digital processes over time. This data is not a legal document and is not to be used as such. This data is not STATSGO or SSURGO certified.

  1. Who distributes the data set? (Distributor 1 of 1)

    USGS BRD's National Wetlands Research Center
    c/o Steve Hartley
    Senior Geographer/GIS Analyst
    700 Cajundome Blvd.
    Lafayette, Louisiana 70506
    USA

    337-266-8543 (voice)
    337-266-8616 (FAX)
    steve_hartley@usgs.gov

    Hours_of_Service: 8:00 am to 4:00 pm CST Monday through Friday
  2. What's the catalog number I need to order this data set?

    NRCS Soil Maps for St. Landry Parish

  3. What legal disclaimers am I supposed to read?

    Although this data has been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the accuracy or utility of the data or any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that this data is directly acquired from a USGS server, and not indirectly through other sources which may have changed the data in some way. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with this data. The USGS shall not be held liable for improper or incorrect use of the data described and/or contained herein.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Not available


Who wrote the metadata?

Dates:
Last modified: 30-May-2002
Last Reviewed: 04-Jun-2002

Metadata author:
Joan C. Kester
USGS BRD's National Wetlands Research Center
Geographer
700 Cajundome Blvd
Lafayette, LA 70506
USA

337-266-8611 (voice)
337-266-8616 (FAX)
joan_kester@usgs.gov

Hours_of_Service: 8:00 am to 4:00 pm CST Monday thru Friday
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.7.33 on Tue Jul 08 13:32:35 2003