Description of Field Research Facilty's 3D survey data file format for the SandyDuck minigrid surveys.

Note: These files (*.3D) were corrected in 1999.  Originally the GPS time stamp on each line 
was incomplete, a result of the post-processing from the original HYPACK files. Otherwise these 
files are identical to the files processed during SandyDuck in 1997.

These files, referred locally as "ISRP 3D" format files, store one survey of a number of profile 
lines collected at the Field  Research Facility (FRF) of the US Army Corps of Engineers located 
in  Duck, NC.  These are ASCII files with one data point per line.  The data  were collected using a 
Trimble 4000 SSE differential GPS survey system and Coastal Oceanographic's HYPACK hydrographic 
survey software. 

During SandyDuck these data were collected using the Coastal Research Amphibious Buggy or CRAB.


                               Sample: ISRP 3-D Format

SD  1  51941110       1    183.000    880.000      2.800   9:18:39.929
SD  1  51941110       2    196.000    880.000      2.100   9:18:40.567
SD  1  51941110       3    203.000    880.000     -1.300   9:18:42.335
SD  1  51941110       4    215.000    880.000     -3.700   9:18:43.663
SD  1  51941110       5    221.000    880.000     -1.900   9:18:44.115
SD  1  51941110       6    246.000    880.000     -0.300   9:18:45.354
SD  1  51941110       7    251.000    880.000     -1.800   9:18:46.543

          Each line uses the following format:

                   Parameter                           Format

                Locality Code                          A2 (SD for "SandyDuck")
                Profile Number                         A3 (1)
                Survey Number                          I4 (  51)
                Date (YRMODA)                          I6 (941110)
                Point number, along the line           I8(  1)
                X coordinate (cross-shore in m)        F11.3  (183.000)
                Y coordinate (longshore in m)          F11.3  (880.000)
                Z coordinate (elevation, m NGVD)       F11.3  (2.800)
                Computer Clock Time (EST)(HHMMSS.)     (9:18:39.929)

Notes:

1) Profile Numbers correspond to HYPACK line numbers
2) Coordinates are relative to a pier-orthogonal system whose origin is located behind the dunes 
and along the FRF's south property boundary.  
3) Elevations are relative to NGVD or 1929.
4) Data points with times of 00:00:00.000 - were dune points, surveyed at the start of the
experiment, and assumed to be unchanged.  These were inserted into every survey and typically 
extend only to the base of the dune (elevation ~3 m).  
5) Units are meters, times are generated by the GPS and converted to EST.
6) Survey numbers are consecutive - for SandyDuck 

For more information about these data and the FRF visit the web site at http://frf.usace.army.mil/ 
or contact either Mike Leffler or Bill Birkemeier at 919-261-3511.  Any use of these data should 
credit the US Army Corps and the Field Research Facility. 

Readme file updated 17Apr2002, wab

US Army Corps of Engineers, Engineer Research and Development Center
Coastal and Hydraulic Laboratory
Field Research Facility, 1261 Duck Rd, Duck, NC 27949
252-261-3511x229, 252-261-4432(fax)
http://frf.usace.army.mil