|The CRAB used for beach surveys.|
USACE has surveyed the beach near Duck regularly since 1981.
There is a single day's survey at http://www.usna.edu/Users/oceano/pguth/downloads/FRF20040719_648_V20050729.dbf .
If you need additional data:
|File||Field Names. Cut and paste into CSV import dialog when prompted|
|Older surveys, ASCII files with .3D and .3DL extensions, space separated. Several of these fields are populated with "NAN" for "not a number", and the data is missing. They will import correctly, but the fields will be blank. If you did not want to create the empty fields, you could name the field as JUNK and MICRODEM will ignore the field when it imports the database.||location survey_no line lat long easting northing distance offline elevation ellipsoid date time seconds|
|Newer surveys, ASCII files with .CSV extension, comma separated.||location,survey_no,line,lat,long,easting,northing,distance,offline,elevation,ellipsoid,date,time,seconds|
When you unzip the annual file from the FRF website, you will have a number of files for the survey dates, generally about 2-4 weeks apart, a graphic showing the survey results, and a metadata file. The "survey_no" will be a line in their unique coordinate system (58 at the north end of the beach, to 190 at the south end of the beach, and "line" will be a sequential number starting when the first surveys were done.
Database The daily files can be imported into a DBF file:
Filter to get a single "survey_no", and the STATS, 2D graphs, 2D graph simple, and plot "distance" versus elevation. Compare this to Topographic Profiles along the same line.
|SURVEY_NO 188, isolated by filtering the database|
|Profile of SURVEY_NO 188 on 2011/10/17 using STATS, 2D graph, 2D graph,
These surveys typically extend farther seaward than the lidar data, which does not extend below the water level for most of the surveys.
The 0 point on the horizontal axis is a location behind the dunes, so it will not be destroyed during a storm. It is over 100 m from the shoreline (which varies both seasonally and annually), and the surveys do not actually survey back to this location.
|Profile of SURVEY_NO on 2004/07/19, with the
profile in red, and the points interpolated from
the DEM in Blue (Edit, DEM, Add interpolated
elevation from DEM).
This is found using STATS, 2D graph, 2D graph, 2 Series.
This only works for the entire profile for those surveys with data below sea level. Others will just have overlapping data on the beach itself.
Contours, 0.5 m contour interval, overlaid on
the LIDAR grid.
Last revision 11/20/2017