NORCAL_TRANSECTS_ST - Short-Term Shoreline Change Rates for Northern California Generated at a 50m Transect Spacing, 1952-2002

A baseline was manually constructed seaward of, and parallel to, the trend of shorelines representing four general time periods (1800s, 1920s-1930s, 1970s, and 1998-2002). Using DSAS, transects were generated with a spacing of 50m and transect-shoreline intersection points were saved to a separate layer. Transects were manually eliminated to prevent calculation of rates in areas where less than four shorelines were intersected.
Long-term rates of shoreline change, in units of m/yr, were calculated at each transect using linear regression applied to all four shoreline positions from the earliest (1800s) to the most recent (derived from lidar). Linear regression was selected because it has been shown to be the most statistically robust quantitative method when a limited number of shorelines are available and it is the most commonly applied statistical technique for expressing shoreline movement and estimating rates of change. Uncertainties for the long-term rates are also reported in units of m/yr and represent a 90% confidence interval for the slope of the regression line. This means with 90% statistical confidence that the true rate of shoreline change falls within the range defined by the reported value plus or minus the error value. The variability around the trend reflects both measurement and sampling errors. Short-term rates of shoreline change, in units of m/yr, were calculated using the endpoint method comparing the 1970s and most recent shoreline position . Process date is estimated.

Data were projected from UTM zone 10 to geographic with Datum shift from NAD27 to NAD83_6
Tool: ArcGIS > ArcToolbox > Toolboxes > Data Management Tools > Project
Command issued:
['GCS_North_American_1983',DATUM['D_North_American_1983', SPHEROID['GRS_1980',6378137.0,298.257222101]], PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]] NAD_1927_To_NAD_1983_6

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

Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata.

Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.

Edited metadata to perform minor edits to bring the metadata up to current PCMSC standards. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata dates to determine which metadata file is most recent.