This U.S. Geological Survey (USGS) data release includes geospatial datasets that were created for the analysis of Virginia and Maryland Atlantic coastal wetland changes over time. Wetland change was determined by assessing two metrics: wetland persistence and land-cover switching. Because seasonal water levels, beach width, and vegetation differences can affect change analyses, only images acquired during the spring (March, April, and May) were included in the wetland-change metrics (N=10). To assess wetland-area trends, including wetland persistence, the total marsh and mixed vegetation classes land-cover types defined by Bernier and others (2015) were reclassified as 1 (wetland presence) and all other classes were reclassified as 0 (wetland absence). When the baseline data (1985) is subtracted from a later dataset, the outcome results in cells with three possible values: 0, 1, or -1, where -1 is wetland loss, 0 is no change (persistence), and 1 is wetland gain.

This U.S. Geological Survey (USGS) data release includes geospatial datasets that were created for the analysis of Virginia and Maryland Atlantic coastal wetland changes over time. Wetland change was determined by assessing two metrics: wetland persistence and land-cover switching. Because seasonal water levels, beach width, and vegetation differences can affect change analyses, only images acquired during the spring (March, April, and May) were included in the wetland-change metrics (N=10). Land-cover switching was evaluated using Landsat images for successive spring image-acquisition dates: 1985–1989, 1989–1994, 1994–1999, 1999–2004, 2004-2009, 2009-2011, 2011-2013, 2013-2014, and 2014-2015. To evaluate land-cover switching, land-cover types defined by Bernier and others (2015) were reclassified as 1 (water), 3 (wetland), or 7 (non-wetland). These values were chosen so the results of subtracting two dates will create unique values for each scenario. For example, if a cell in 1994 is classified as land and in 1989 was wetland, the result (1994-1989 or 7-3) is 4. If the cell in 1994 is wetland and in 1989 was water (3-1) the result is 2. With this analysis, each two-date combination results in a raster that identifies wetland-land-water conversions, such that water-to-land is -6, wetland-to-land is -4, water-to-wetland is -2, wetland-to-water equals 2, land-to-wetland is 4, and land-to-water is 6.

This U.S. Geological Survey (USGS) data release includes geospatial datasets that were created for the analysis of Virginia and Maryland Atlantic coastal wetland changes over time. Wetland change was determined by assessing two metrics: wetland persistence and land-cover switching. Because seasonal water levels, beach width, and vegetation differences can affect change analyses, only images acquired during the spring (March, April, and May) were included in the wetland-change metrics (N=10). Land-cover switching was evaluated using Landsat images for successive spring image-acquisition dates: 1985–1989, 1989–1994, 1994–1999, 1999–2004, 2004-2009, 2009-2011, 2011-2013, 2013-2014, and 2014-2015. To evaluate land-cover switching, land-cover types defined by Bernier and others (2015) were reclassified as 1 (water), 3 (wetland), or 7 (non-wetland). These values were chosen so the results of subtracting two dates will create unique values for each scenario. For example, if a cell in 1994 is classified as land and in 1989 was wetland, the result (1994-1989 or 7-3) is 4. If the cell in 1994 is wetland and in 1989 was water (3-1) the result is 2. With this analysis, each two-date combination results in a raster that identifies wetland-land-water conversions, such that water-to-land is -6, wetland-to-land is -4, water-to-wetland is -2, wetland-to-water equals 2, land-to-wetland is 4, and land-to-water is 6.

This U.S. Geological Survey (USGS) data release includes geospatial datasets that were created to analyze wetland changes along the Virginia and Maryland Atlantic coasts between 1984 and 2015. Wetland change was determined by assessing two metrics: wetland persistence and land-cover switching. Because seasonal water levels, beach width, and vegetation differences can affect change analyses, only images acquired during the spring (March, April, and May) were included in the wetland-change metrics (N=10). USGS Data Series 968 (Bernier and others, 2015) presented data that were derived from Landsat 5 and Landsat 8 imagery from 1984 to 2014, including wetland and terrestrial habitat extents; open-ocean, back-barrier, and estuarine mainland shoreline positions; and sand-line positions along the estuarine mainland and barrier shorelines from Assateague Island, Maryland to Metompkin Island, Virginia. As part of the wetland-change analyses, two additional satellite images (17-April-1985 and 05-May-2015) were processed and classified using the methods described by Bernier and others (2015) to provide a more complete time series dataset. One additional image (26-April-1994) was reprocessed to correct a classification error that was identified when comparing wetland and total analysis extents among all images.

This U.S. Geological Survey (USGS) data release includes geospatial datasets that were created to analyze wetland changes along the Virginia and Maryland Atlantic coasts between 1984 and 2015. Wetland change was determined by assessing two metrics: wetland persistence and land-cover switching. Because seasonal water levels, beach width, and vegetation differences can affect change analyses, only images acquired during the spring (March, April, and May) were included in the wetland-change metrics (N=10). USGS Data Series 968 (Bernier and others, 2015) presented data that were derived from Landsat 5 and Landsat 8 imagery from 1984 to 2014, including wetland and terrestrial habitat extents; open-ocean, back-barrier, and estuarine mainland shoreline positions; and sand-line positions along the estuarine mainland and barrier shorelines from Assateague Island, Maryland to Metompkin Island, Virginia. As part of the wetland-change analyses, two additional satellite images (17-April-1985 and 05-May-2015) were processed and classified using the methods described by Bernier and others (2015) to provide a more complete time series dataset. One additional image (26-April-1994) was reprocessed to correct a classification error that was identified when comparing wetland and total analysis extents among all images.

The U.S. Geological Survey has a long history of responding to and documenting the impacts of storms along the Nation’s coasts and incorporating these data into storm impact and coastal change vulnerability assessments. These studies, however, have traditionally focused on sandy shorelines and sandy barrier-island systems, without consideration of impacts to coastal wetlands. The goal of the Barrier Island and Estuarine Wetland Physical Change Assessment project is to integrate a wetland-change assessment with existing coastal-change assessments for the adjacent sandy dunes and beaches, initially focusing on Assateague Island along the Maryland and Virginia coastline. Assateague Island was impacted by waves and storm surge associated with the passage of Hurricane Sandy in October 2012, including erosion and overwash along the ocean-facing sandy shoreline as well as erosion and overwash deposition in the back-barrier and estuarine bay environments. This report serves as an archive of data that were derived from Landsat 5 and Landsat 8 imagery from 1984 to 2014, including wetland and terrestrial habitat extents; open-ocean, back-barrier, and estuarine mainland shoreline positions; and sand-line positions along the estuarine mainland and barrier shorelines from Assateague Island, Maryland to Metompkin Island, Virginia. The geographic information system data files with accompanying formal Federal Geographic Data Committee (FGDC) metadata can be downloaded from http://pubs.usgs.gov/ds/0968/ds968_data.html.

The U.S. Geological Survey has a long history of responding to and documenting the impacts of storms along the Nation’s coasts and incorporating these data into storm impact and coastal change vulnerability assessments. These studies, however, have traditionally focused on sandy shorelines and sandy barrier-island systems, without consideration of impacts to coastal wetlands. The goal of the Barrier Island and Estuarine Wetland Physical Change Assessment project is to integrate a wetland-change assessment with existing coastal-change assessments for the adjacent sandy dunes and beaches, initially focusing on Assateague Island along the Maryland and Virginia coastline. Assateague Island was impacted by waves and storm surge associated with the passage of Hurricane Sandy in October 2012, including erosion and overwash along the ocean-facing sandy shoreline as well as erosion and overwash deposition in the back-barrier and estuarine bay environments. This report serves as an archive of data that were derived from Landsat 5 and Landsat 8 imagery from 1984 to 2014, including wetland and terrestrial habitat extents; open-ocean, back-barrier, and estuarine mainland shoreline positions; and sand-line positions along the estuarine mainland and barrier shorelines from Assateague Island, Maryland to Metompkin Island, Virginia. The geographic information system data files with accompanying formal Federal Geographic Data Committee (FGDC) metadata can be downloaded from http://pubs.usgs.gov/ds/0968/ds968_data.html.

The analyses of landscape change presented in this dataset use Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM) and Operational Land Imager (OLI) to assess changes in land area through time. All cloud-free dates of imagery from 1984 through early 2016 were used in this analysis. This amounted to a total of 174 dates of imagery which were analyzed. No water level restrictions were used during the image selection process as gages with a period of record sufficient for this analysis are not available nearby. Persistent loss and gain data are presented for 1984-2016.

Over time, as sea levels rise and land subsides, marsh transgression can occur. As shorelines erode and the marsh slowly transgresses landward into the upland, valuable coastal habitat simultaneously is lost and gained. If the shoreline erosion is faster than the rate of upland transgression, the result is a net loss in coastal wetlands. This dataset represents a marsh area change analysis for the Point Aux Chenes and Grand Bay estuaries in Mississippi and Alabama from 1848-1957/1958, 1848-2019/2022, and 1957/1958-2019/2022. Classified habitats are also included for 1848, 1957/1958 and 2022. Shoreline and upland boundary positional data were obtained from multiple data sources, including National Oceanic and Atmospheric Administration (NOAA) topographic sheets (t-sheets) and WorldView 2 high resolution satellite imagery. Two dates were chosen for the 1957/1958 (henceforth referred to as 1957), and 2019/2022 (henceforth be referred to as 2022) to provide complete coverage. Shorelines and upland lines were converted into raster data (.tif) to calculate marsh habitat area change over time. This data release contains a raster data for 1848, 1957, and 2022, as well as change rasters for 1848-1957, 1957-2022, and 1848-2022.

The U.S. Geological Survey has a long history of responding to and documenting the impacts of storms along the Nation’s coasts and incorporating these data into storm impact and coastal change vulnerability assessments. These studies, however, have traditionally focused on sandy shorelines and sandy barrier-island systems, without consideration of impacts to coastal wetlands. The goal of the Barrier Island and Estuarine Wetland Physical Change Assessment project is to integrate a wetland-change assessment with existing coastal-change assessments for the adjacent sandy dunes and beaches, initially focusing on Assateague Island along the Maryland and Virginia coastline. Assateague Island was impacted by waves and storm surge associated with the passage of Hurricane Sandy in October 2012, including erosion and overwash along the ocean-facing sandy shoreline as well as erosion and overwash deposition in the back-barrier and estuarine bay environments. This report serves as an archive of data that were derived from Landsat 5 and Landsat 8 imagery from 1984 to 2014, including wetland and terrestrial habitat extents; open-ocean, back-barrier, and estuarine mainland shoreline positions; and sand-line positions along the estuarine mainland and barrier shorelines from Assateague Island, Maryland to Metompkin Island, Virginia. The geographic information system data files with accompanying formal Federal Geographic Data Committee (FGDC) metadata can be downloaded from http://pubs.usgs.gov/ds/0968/ds968_data.html.