Logical_Consistency_Report:
Landsat standard data products, processed using the Level 1 Product Generation System (LPGS), were downloaded from the USGS Earth Resources Observation and Science (EROS) Center data archives.
Even after using a hybrid classification approach, some areas that were classified as wet marsh in the final thematic raster dataset appeared, upon visual inspection, to include submerged aquatic vegetation and submerged sand flats that would be more appropriately classified as open water. These ambiguities are not consistent through time but most commonly occur in Sinepuxent Bay south of Ocean City Inlet, north of Green Run Bay and Pirate Islands, in impoundments behind Chincoteague Island, and at Chincoteague Inlet. Similarly, in some instances, areas that were classified as water in the final thematic raster dataset were interpreted as wet sand on visual inspection. This most commonly occurs along the narrowest part of Assateague Island south of Ocean City Inlet, at the Tom’s Cove spit, and along Metompkin Island. Additionally, some near-shore estuarine areas exhibit “speckling” caused by misclassification of isolated higher reflectance pixels within the water body. No manual cleaning of open-water speckling or potentially misclassified pixels was performed.
The primary sand lines represent the continuous inland extent of sand behind the open-ocean shoreline; lines representing sand extents or vegetation “islands” larger than eleven pixels (about 10,000 m2) were also included. Similarly, the primary back-barrier shoreline represents the continuous back-barrier land extent; however, shorelines around back-barrier marsh islands larger than 10,000 m2 were also included in the shoreline datasets. Line features were manually edited on the basis of visual comparison with both the original Landsat image and the final thematic raster dataset; for example, classified land areas that were visually interpreted as open water were excluded from the back-barrier shoreline or back-barrier island extents.
Completeness_Report:
Nineteen Landsat 5 Thematic Mapper (TM) and four Landsat 8 Operational Land Imager (OLI) image acquisition dates were selected for analysis. Image acquisition dates correspond to 5-year intervals beginning in 1984 supplemented with additional images from intervening years for which high-resolution aerial photography was also analyzed (Guy, 2015). If available, spring (April preferred) and late fall (November preferred) image acquisition dates were used for each analysis year. The spring and fall images were supplemented with additional scenes corresponding to aerial photography acquisition dates (Guy, 2015). A gap in imagery dates from August 31, 2011 to April 14, 2013, corresponding to the decommissioning of the Landsat 5 TM mission and the first data available from the recently launched Landsat 8 OLI mission. Data from the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) satellite are available for this time period; however, data gaps exist over the study area in all Landsat 7 images acquired since May 2003 due to the failure of the scan line corrector early in May 2003, limiting the use of these Landsat 7 data in quantitative land-change analyses.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Geodetic accuracy of the Standard Terrain Correction (Level 1T) data product depends on the accuracy of the ground control points and the resolution of the DEM used.
Lineage:
Process_Step:
Process_Description:
Each Landsat Level 1 data product was stacked into a composite multi-band image file using Intergraph Corporation ERDAS IMAGINE 2014 software. The six reflective bands (visible blue, green, and red; near infrared; and two short-wave infrared bands) for each sensor were stacked and used in subsequent processing and analyses.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Julie Bernier
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8000
Contact_Electronic_Mail_Address: jbernier@usgs.gov
Process_Step:
Process_Description:
The composite multi-band image files were converted to at-sensor radiance and top-of-atmosphere (TOA) reflectance using Intergraph Corporation ERDAS IMAGINE 2014 software. Radiometric processing reduces scene-to-scene variability due to gain changes between scenes or differences in solar zenith angles, exoatmospheric solar irradiance, and the earth-sun distance resulting from different acquisition dates and times.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Julie Bernier
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8000
Contact_Electronic_Mail_Address: jbernier@usgs.gov
Process_Step:
Process_Description:
For each image acquisition date, adjacent scenes (Worldwide Reference System 2, path 14 row 33 and path 14 row 34) were mosaicked to a single image and clipped to the study area extent.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Julie Bernier
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8000
Contact_Electronic_Mail_Address: jbernier@usgs.gov
Process_Step:
Process_Description:
Image classification was performed using Intergraph Corporation ERDAS IMAGINE 2014 software. A hybrid classification approach was used to minimize misclassification of small interior water bodies and tidal channels with surrounding marsh environments:
(1) A 3×3 (pixel) edge enhancement convolution filter was applied to the radiometrically corrected, mosaicked images to enhance small water features;
(2) Unsupervised classification was performed on the edge-enhanced image to identify and extract water areas;
(3) Water areas from (2) were masked from the non edge-enhanced image and unsupervised classification of the remaining pixels was grouped into seven classes (water, wet marsh, marsh, forested, mixed vegetation, vegetated bare earth, and bare earth); and
(4) Results of (2) and (3) were merged to generate a final thematically classified raster dataset.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Julie Bernier
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8000
Contact_Electronic_Mail_Address: jbernier@usgs.gov
Process_Step:
Process_Description:
Line feature classes representing open-ocean, back-barrier, and estuarine mainland shoreline positions and beach/sand-line positions were generated from from the final thematic raster datasets using the Raster to Polygon and Polygon to Line tools in ArcGIS 10.2.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Julie Bernier
Contact_Position: Geologist
Contact_Address:
Address_Type: Mailing and physical
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8000
Contact_Electronic_Mail_Address: jbernier@usgs.gov
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20201013
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
