Digital Shoreline Analysis System version 4.3 shoreline intersection points used to calculate short-term (Linear Regression Rate) shoreline change statistics for the North Shore coastal region from North Salisbury at the New Hampshire border to the west side of Deer Island in Boston Harbor (NorthShore_intersects_STlr.shp)

The bias and uncertainty data associated with the 2000 lidar shoreline were previously published by the USGS (OFR 2012-1119) and are organized in two separate files for the North Shore region boundaries of this study (NewEnglandN_shorelines_uncertainty.dbf and GreaterBoston_shorelines_uncertainty.dbf ). Therefore, the rate calculations were run twice (once for each uncertainty table) to compute a complete set of bias-corrected rates for the North Shore region.
The NewEnglandN_shorelines_uncertainty.dbf file and the GreaterBoston_shorelines_uncertainty.dbf files were imported to the geodatabase containing the North Shore data. The tables were renamed to match the corresponding shoreline shapefiles (NewEnglandN_shorelines_uncertainty.dbf was renamed NorthShoreA_shorelines_uncertainty.dbf, and GreaterBoston_shorelines_uncertainty.dbf was renamed NorthShoreB_shorelines_uncertainty).
Rate Calculations Performed using DSAS v4.3, for the North Shore A subregion on selected shorelines (shoreline years 1970 2009). Parameters Used: shoreline layer=NorthShoreA_shorelines, shoreline date field=Date_, shoreline uncertainty field name=Uncy (additional shoreline data stored in NorthShoreA_shoreline_uncertainty.dbf), the default accuracy=10.8 meters, shoreline intersection parameters=nearest, stats calculations=[Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), Linear Regression Rate (LRR)], shoreline threshold=3, confidence interval=90%, Output rate table name=NorthShoreA_transects_rates_20121127_113618. Output intersects table name=NorthShoreA_transects_intersect_20121127_113618.dbf.
This process step and all subsequent process steps were performed by Theresa Smith.

The shoreline intersects output table contains X- and Y-coordinate information for each shoreline measurement on DSAS transects. This table (NorthShoreA_transects_intersect_20121127_113618.dbf) was used to create a temporary event theme to preview the transect/shoreline measurement locations in ArcMap. The intersects file was right-clicked in the ArcMap (v.10) table of contents. "Display XY data..." was chosen from the pop-up menu. A new Display XY Data window opens and the following parameters were entered: X Field: IntersectX; Y Field; Intersect Y; Z Field: <None>; Coordinate System of Input Coordinates: NAD_1983_Massachusetts_Mainland_FIPS_2001.

The temporary event theme is saved to a shapefile by right-clicking the NorthShoreA_transects_intersect_20121127_113618 Events layer in the table of contents (ArcMap 10) and choosing Data > Export Data from the pop-up menu. This opens an Export Data window where the following parameters were entered: Export: All features; Select "Use the same coordinate system as this layer's source data"; Output feature class: NorthShoreA_intersects_STlr.shp.

The transects_rates output feature class for the North Shore A section (NorthShoreA_transects_rates_STlr.shp) was joined to the intersects feature class (NorthShoreA_intersects_STlr) in ArcMap v.10 by right-clicking on the intersects layer > joins and relates > join > join attributes from a table. Parameters: join field - TransectID; table to join - NorthShoreA_transects_rates_STlr.dbf; field in table: TransectID; join options - keep all records. The joined feature class' attribute table was displayed in ArcMap (v.10). Using standard editing tools, intersect data corresponding to transects 923-3957 were deleted from the file, as they extend outside the North Shore A subregion.

Rate Calculations Performed using DSAS v4.3, for the North Shore B subregion on selected shorelines (shoreline years 1970 - 2009). Parameters Used: shoreline layer=NorthShoreB_shorelines, shoreline date field=Date_, shoreline uncertainty field name=Uncy (additional shoreline data stored in NorthShoreB_shoreline_uncertainty.dbf), the default accuracy=10.8 meters, shoreline intersection parameters=nearest, stats calculations=[Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), Linear Regression Rate (LRR)], shoreline threshold=3, confidence interval=90%, Output rate table name=NorthShoreB_transects_rates_20120207_130143.dbf. Output intersects table name=NorthShoreB_transects_intersect_20120207_130143.dbf

The shoreline intersects output table contains X- and Y-coordinate information for each shoreline measurement on DSAS transects. This table (NorthShoreB_transects_intersect_20120207_130143.dbf) was used to create a temporary event theme to preview the transect/shoreline measurement locations in ArcMap. The intersects file was right-clicked in the ArcMap (v.10) table of contents. "Display XY data..." was chosen from the pop-up menu. A new Display XY Data window opens and the following parameters were entered: X Field: IntersectX; Y Field; Intersect Y; Z Field: <None>; Coordinate System of Input Coordinates: NAD_1983_Massachusetts_Mainland_FIPS_2001.

The temporary event theme is saved to a shapefile by right-clicking the NorthShoreB_transects_intersect_20120207_130143 Events layer in the table of contents (ArcMap 10) and choosing Data > Export Data from the pop-up menu. This opens an Export Data window where the following parameters were entered: Export: All features; Select "Use the same coordinate system as this layer's source data"; Output feature class: NorthShoreB_intersects_STlrshp.

The transects_rates output feature class for the North Shore B section (NorthShoreB_transects_rates_STlr.shp) was joined to the intersects feature class (NorthShoreB_intersects_STlr) in ArcMap v.10 by right-clicking on the intersects layer > joins and relates > join > join attributes from a table. Parameters: join field - TransectID; table to join - NorthShoreB_transects_rates_STlr.dbf; field in table: TransectID; join options - keep all records. The joined feature class' attribute table was displayed in ArcMap (v.10). Using standard editing tools, intersect data corresponding to transects 1-922 were deleted from the file, as they extend outside the North Shore B subregion.

The NorthShoreA_intersects_STlr and NorthShoreB_intersects_STlr feature classes were exported from the personal geodatabase back to a shapefile in ArcCatalog (v.10) by right-clicking on one of the intersects files > Export > To Shapefile (multiple). The shapefiles were then merged in Esri's ArcToolbox (v.10), Data Management Tools > General > Merge, to produce one set of results for display and publication purposes encompassing the whole extent of the North Shore region. The file was renamed NorthShore_intersects_STlr.shp

The merged transect shapefile was projected in Esri's ArcToolbox (v.10) > Data Management Tools > Projections and Transformations > Feature > Project. Parameters: input projection - NAD_1983_StatePlane_Massachusetts_Mainland_FIPS_2001; output projection - geographic coordinates (NAD83); transformation - none.

Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). Attempted to modify http to https where appropriate. Added a landing page link as the first link in the identification section. Fixed online link to DSAS cross-reference. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.

Added keywords section with USGS persistent identifier as theme keyword.