Description: To quantify rates of change (erosion or accretion) along coastal and estuarine shorelines in Maryland, the Maryland Geological Survey (MGS), and the U.S. Geological Survey (USGS), installed and ran a computer program, the Digital Shoreline Analysis System (DSAS), using as input a series of digital shoreline vectors dating from 1841-1995. Shorelines were derived from three sources: (1) maps from a Historical Shorelines and Erosion Rates Atlas (Conkwright, 1975), (2) Coastal Survey maps (topographic or T-sheets) produced by the National Ocean Service (NOS), a branch of the National Oceanic and Atmospheric Administration (NOAA), and (3) a digital wetlands delineation based on photo interpretation of digital orthophoto quarter quads. DSAS constructed a “baseline” landward of and approximately parallel to the shorelines, inserted nodes every 20 m along the baseline, and cast straight-line transects from each node, perpendicular to the baseline, across the shorelines. Based on the time elapsed and the along-transect distance between shoreline pairs, DSAS calculated rates of change for each transect. Subsequently, updates began in 2015 is updating by county the DSAS process using newer Shoreline data and refined calculations to update the Rates of Change erosion values by county. Currently Anne Arundel, Baltimore, Calvert, Harford and Prince George's counties have the newest erosion rate values contained in this Data set.
Description: This conflated baseline consist of two Digital Shoreline Analysis System (DSAS) Process runs. The original In 2000, the Maryland Geological Survey (MGS) was awarded a Coastal Zone Management grant to complete the acquisition of a recent (ca. 1990) digital shoreline for the coastal regions of Maryland -- the Chesapeake Bay, its tributaries, the coastal bays, and the Atlantic coast. MGS contracted the services of EarthData International, Inc. (EDI), currently of Frederick, Md., to extract shorelines from an existing wetlands delineation, which was based on photo interpretation of 3.75-minute digital orthophoto quarter quads (DOQQs). The 2000 baseline which were not created seaward includes all Maryland shoreline areas except for Anne Arundel, Baltimore, Calvert, Harford and Prince George's counties currently. The newest (2015) updated baselines were created offshore (seaward) of the shorelines utilized in DSAS analysis. The baselines were created by 1) buffering at a distance of 10m around the master shoreline feature class converting the buffer polygon to a line, and erasing the landward portion of the buffer line; and 2) manually digitizing baselines up the centerline of tributaries/rivers and other areas where baselines were needed but the buffer-created baselines did not reach.
Description: The Maryland Geological Survey (MGS) developed this shoreline feature class as part of a project to calculate updated rate of change information for Anne Arundel, Baltimore, Harford and Prince George's Counties. These 5 counties have specifics related to each for the shoreline erosion anaylsis and the details are designated within the metadata. This shoreline data set spans the time period 1932-2010, and was used as input to the U.S. Geological Survey (USGS) Digital Shoreline Analysis System (DSAS) v4.3 program to calculate long-term and short-term rates of change (erosion and accretion).
Description: This Legacy Historical Shorelines is a subset of the Maryland Historical Shorelines data set with 5 counties being excluded from the shorelines which are Anne Arundel, Balimore, Calvert, Harford and Prince George's County. The remaining counties have these digital shoreline vectors which are used to overlay orthophoto base map rasters of the Maryland shoreline and show historical shoreline locations in relation to the Rates of Change (ROC) erosion level transects data. Acquired as part of multi-year Shoreline Changes mapping project to show erosion and other shoreline shifts along Maryland's Chesapeake Bay and tidal tributaries. The newer county shoreline data can be viewed using the "Limited ROC Shorelines by Decade" map layer and this Legacy Shoreline layer will be replaced by the Limited ROC Shorelines by Decade as counties are updated over time.
Name: Anne Arundel 10 years Shoreline Erosion Level
Display Field: DSAS_DATE
Type: Feature Layer
Geometry Type: esriGeometryPolyline
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1993-2010 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Anne Arundel County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Anne Arundel County; and 2) portions of the Maryland Department of Natural Resources (MD DNR) Critical Area Commission (CAC) digital shoreline for Anne Arundel County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1990s shoreline and the ca. 2000/2010 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 10-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) No data (rates not delivered; calculated rates suspect). The NOAA CUSP shoreline represents the shoreline position in Anne Arundel County between the years 2005-2010. The CAC shoreline represents the shoreline position in Anne Arundel County in 2007. In Anne Arundel County, the NOAA CUSP data set covered all shoreline in the county with the exception of the Patuxent River along the western county border. As such, MGS utilized the CAC shoreline data set in the Patuxent River area. To identify which shoreline source is responsible for a shoreline segment, view the "DSAS_SRC" attribute table field -- "CAC" indicates a shoreline sourced from MD DNR CAC data set; "NOAA CUSP" indicates a shoreline sourced from the NOAA CUSP data set. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Name: Anne Arundel 30 years Shoreline Erosion Level
Display Field: DSAS_DATE
Type: Feature Layer
Geometry Type: esriGeometryPolyline
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1971-2010 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Anne Arundel County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Anne Arundel County; and 2) portions of the Maryland Department of Natural Resources (MD DNR) Critical Area Commission (CAC) digital shoreline for Anne Arundel County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1970s shoreline and the ca. 2000/2010 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 30-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) No data (rates not delivered; calculated rates suspect). The CUSP shoreline represents the shoreline position in Anne Arundel County between the years 2005-2010. The CAC shoreline represents the shoreline position in Anne Arundel County in 2007. In Anne Arundel County, the NOAA CUSP data set covered all shoreline in the county with the exception of the Patuxent River along the western county border. As such, MGS utilized the CAC shoreline data set in the Patuxent River area. To identify which shoreline source is responsible for a shoreline segment, view the "DSAS_SRC" attribute table field -- "CAC" indicates a shoreline sourced from MD DNR CAC data set; "NOAA CUSP" indicates a shoreline sourced from the NOAA CUSP data set. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1994-2011 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Baltimore County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Baltimore County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1990s shoreline and the ca. 2000/2010 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 10-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) No data (rates not delivered; calculated rates suspect). Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1972-2011 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Baltimore County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Baltimore County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1970s shoreline and the ca. 2000/2010 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 30-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) No data (rates not delivered; calculated rates suspect). Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1993-2007 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Calvert County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Calvert County; and 2) portions of the Maryland Department of Natural Resources (MD DNR) Critical Area Commission (CAC) digital shoreline for Calvert County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1990s shoreline and the ca. 2000 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 10-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) Rates not delivered (calculated rates suspect). The NOAA CUSP shoreline represents the shoreline position in Calvert County between the years 2005-2006. The CAC shoreline represents the shoreline position in Calvert County in 2007. In Calvert County, the NOAA CUSP data set covered approximately 90% of the shoreline in the county. MGS supplemented the NOAA CUSP data with CAC data in the following areas where NOAA CUSP data was missing: Hunting Creek; upper 2/3 of Hall Creek; and Patuxent River, from approximately 1 kilometer south of the Merkle Wildlife Sanctuary, north to (and including) Lyons Creek. To identify which shoreline source is responsible for a shoreline segment, view the "DSAS_SRC" attribute table field -- "CAC" indicates a shoreline sourced from MD DNR CAC data set; "NOAA CUSP" indicates a shoreline sourced from the NOAA CUSP data set. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1960-2007 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Calvert County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Calvert County; and 2) portions of the Maryland Department of Natural Resources (MD DNR) Critical Area Commission (CAC) digital shoreline for Calvert County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1960s shoreline and the ca. 2000 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 40-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) Rates not delivered (calculated rates suspect). The CUSP shoreline represents the shoreline position in Calvert County between the years 2005-2006. The CAC shoreline represents the shoreline position in Calvert County in 2007. In Calvert County, the NOAA CUSP data set covered approximately 90% of the shoreline in the county. MGS supplemented the NOAA CUSP data with CAC data in the following areas where NOAA CUSP data was missing: Hunting Creek; upper 2/3 of Hall Creek; and Patuxent River, from approximately 1 kilometer south of the Merkle Wildlife Sanctuary, north to (and including) Lyons Creek. To identify which shoreline source is responsible for a shoreline segment, view the "DSAS_SRC" attribute table field -- "CAC" indicates a shoreline sourced from MD DNR CAC data set; "NOAA CUSP" indicates a shoreline sourced from the NOAA CUSP data set. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1994-2007 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Harford County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Harford County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1990s MGS shoreline and the ca. 2000 NOAA CUSP shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 10-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) Rates not delivered (calculated rates suspect). The NOAA CUSP shoreline represents the shoreline position in Harford County between the years 2005-2007. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1972-2007 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Harford County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Harford County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1970s NOAA National Shoreline data sets and the ca. 2000 NOAA CUSP shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 30-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) Rates not delivered (calculated rates suspect). The CUSP shoreline represents the shoreline position in Harford County between the years 2005-2007. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Name: Prince Georges 10 years Shoreline Erosion Level
Display Field: SOURCE_ID
Type: Feature Layer
Geometry Type: esriGeometryPolyline
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1993-2010 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Prince George's County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Prince George's County; and 2) portions of the Maryland Department of Natural Resources (MD DNR) Critical Area Commission (CAC) digital shoreline for Prince George's County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1990s shoreline and the ca. 2000/2010 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 10-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) Rates not delivered (calculated rates suspect). The NOAA CUSP shoreline represents the shoreline position in Prince George's County between the years 2005-2010. The CAC shoreline represents the shoreline position in Prince George's County in 2007. In Prince George’s County, the NOAA CUSP data set covered approximately 60% of the shoreline in the county. MGS decided to supplement the NOAA CUSP data with CAC data in the following areas where NOAA CUSP data was missing: Anacostia River, from approximately the Bladensburg Road bridge, north to the Decatur Street bridge; Northwest Branch Anacostia River, from approximately the 38th Street bridge, south to its confluence with the Anacostia River; the lower reaches of Swanson Creek, west of Chalk Point; Spice Creek and an unnamed creek north of Spice Creek; and Patuxent River and its major tributaries, from approximately the Merkle Wildlife Sanctuary, north to the upper reaches of the Patuxent River. To identify which shoreline source is responsible for a shoreline segment, view the "DSAS_SRC" attribute table field -- "CAC" indicates a shoreline sourced from MD DNR CAC data set; "NOAA CUSP" indicates a shoreline sourced from the NOAA CUSP data set. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.
Name: Prince Georges 30 years Shoreline Erosion Level
Display Field: SOURCE_ID
Type: Feature Layer
Geometry Type: esriGeometryPolyline
Description: To quantify shoreline rates of change (erosion or accretion), Maryland Geological Survey (MGS) used historical and recent shorelines spanning 1972-2010 as input into the Digital Shoreline Analysis System (DSAS) Version 4.3. DSAS, a computer program developed by the U.S. Geological Survey (USGS), determines linear rates of shoreline change along closely spaced, shore-normal transects. Based on DSAS output, MGS assigned generalized rate of change categories as attributes to a recent shoreline for Prince George's County. This recent shoreline consisted of the National Oceanic and Atmospheric Administration (NOAA) Continually Updated Shoreline Product (CUSP) digital shoreline currently available for Prince George's County; and 2) portions of the Maryland Department of Natural Resources (MD DNR) Critical Area Commission (CAC) digital shoreline for Prince George's County. Based on the results of an End Point Rate (EPR) analysis on the ca. 1970s shoreline and the ca. 2000/2010 shoreline (recent shoreline), MGS grouped the rate results into the following general categories: (a) No change (-0.01 to 0.01 feet/year), (b) Accretion (greater than 0.01 feet/year), (c) Slight erosion rate (0 to -2 feet/year), (d) Low erosion rate (-2 to -4 feet/year), (e) Moderate erosion rate (-4 to -8 ft/yr), (f) High erosion rate (greater than -8 feet/year), (g) Protected, (h) No data (insufficient shorelines to calculate 30-year EPR rate), (i) No data (no transects cast; unprotected or unknown shoreline condition), and (j) Rates not delivered (calculated rates suspect). The CUSP shoreline represents the shoreline position in Prince George's County between the years 2005-2010. The CAC shoreline represents the shoreline position in Prince George's County in 2007. In Prince George’s County, the NOAA CUSP data set covered approximately 60% of the shoreline in the county. MGS decided to supplement the NOAA CUSP data with CAC data in the following areas where NOAA CUSP data was missing: Anacostia River, from approximately the Bladensburg Road bridge, north to the Decatur Street bridge; Northwest Branch Anacostia River, from approximately the 38th Street bridge, south to its confluence with the Anacostia River; the lower reaches of Swanson Creek, west of Chalk Point; Spice Creek and an unnamed creek north of Spice Creek; and Patuxent River and its major tributaries, from approximately the Merkle Wildlife Sanctuary, north to the upper reaches of the Patuxent River. To identify which shoreline source is responsible for a shoreline segment, view the "DSAS_SRC" attribute table field -- "CAC" indicates a shoreline sourced from MD DNR CAC data set; "NOAA CUSP" indicates a shoreline sourced from the NOAA CUSP data set. Negative rate of change values indicate erosion, and positive values indicate accretion. In general, MGS tried to attribute lengths of shoreline of at least 80 meters in length sharing similar rates of change.