Digital Shoreline Analysis System version 4.3 Transects with Short-Term Linear Regression Rate Calculations for Texas west (TXwest)

Transect features generated using DSAS v4.3 in ArcMap 10.2. Parameters Used: baseline layer=TXwest_baseline, baseline group field=NULL, transect spacing=50 meters, transect length=2000 meters, cast direction=AUTO-DETECT, baseline location=offshore, cast method=smoothed, smoothing distance=2500 meters, flip baselines=not selected. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the website at: https://woodshole.er.usgs.gov/project-pages/DSAS/version4/ This process step and all subsequent process steps were performed by the same person: M.G. Kratzmann.

Rate calculations performed in DSAS v4.3 using ArcMap v10.2 on selected shoreline features only (Select by Attributes, [Year]>=1960) with the following criteria: 1) they contained three or more shorelines required to compute short-term linear regression shoreline change analysis (a shoreline from the 1960s-70s, the modern (lidar-derived or 1990s) shoreline, and at least one other shoreline from the 1960s to present); 2) they contained the two minimum shorelines required to compute short-term end point shoreline change analysis (a shoreline from the 1960s-70s and the modern (lidar-derived or 1990s) shoreline). In TXwest, the shoreline date range for short-term linear regression rates is 1960 to 2001. Shoreline uncertainty table added to ArcMap project (TXwest_shorelines_uncertainty.dbf) and used by DSAS to apply bias-correction to distance measurements established by transects. Parameters Used: shoreline layer=TXwest_shorelines, shoreline date field=Date_, shoreline uncertainty field name=Uncy, the default uncertainty=5.1 meters, shoreline intersection parameters=closest, stats calculations=[End Point Rate (EPR), Linear Regression Rate (LRR)], shoreline threshold=2, confidence interval=90%, Output rate table name=TXwest_transects_rates_20150908_154739.

Shoreline rates table (TXwest_transects_rates_20150908_154739.dbf) was joined to the transect feature class in ArcMap v10.2 by right-clicking on the transect layer > joins and relates > join > join attributes from a table. Parameters: join field - ObjectID; table to join - TXwest_transects_rates_20150908_154739; field in table: TransectID; join options - keep only matching records.

Transects containing linear regression rates in the joined transect feature class were selected and exported to a shapefile (TXwest_STlrr_rates.shp) in ArcMap v10.2 by right-clicking the transect layer > data > export data, permanently linking the joined rate fields to the transect attribute table. Linear regression rates are reported with preference when both rate types exist for a given transect. In TXwest, linear regression rates are reported for the entire subregion.

Any transects that did not cross the modern (lidar-derived or 1990s) shoreline were deleted using standard editing tools in ArcMap v10.2.

The short-term linear regression rate transects were manually deleted for any stretch of alongshore coast that had fewer than 90% coverage for a 1 kilometer stretch (18 or more transects out of 20 for 50-meter spacing). In other words there will only be 1 kilometer or larger spans of short-term rate calculations.

The exported transect shapefile was projected in Esri's ArcToolbox (v10.2) > Data Management Tools > Projections and Transformations > Project. Parameters: input projection - UTM zone 14N (WGS 84); output projection- geographic coordinates (WGS 84); transformation = none.

Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.

Added keywords section with USGS persistent identifier as theme keyword.