chanwest_bath.txt - Sidescan sonar bathymetry image of Channel West in the Nearshore Benthic Habitat Mapping Project S. California map series.

Title:

Abstract:

The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the Santa Barbara Channel area was mosaicked from data collected in 2005. A 234 kHz Interferometric Submetix Swath Bathy Sonar System; SEA Swath Processor, v. 2.05, SEA Grid Processor v. 2.05, was used for geophysical surveying. The 2005 survey was navigated with a CodaOctopus, Model F180, Differential Global Positioning System (DGPS). A KVH Industries Inc. azimuth digital gyro-compass provided ship headings with 0.5 degree accuracy. Navigation data were recorded using Yo-Nav version 1.19 (Gann, 1992). The sidescan fish was towed approximately 30 m above the seafloor. The distance of the fish behind the ship was not known during this survey and must be estimated when the data are processed in order to produce the sidescan image mosaics. The resolution of the processed data mosaics is 0.2 m. The data are presented here at a resolution of 1 m. This is one of a collection of digital files of a geographic information system of spatially referenced data related to the USGS Coastal and Marine Geology Program Nearshore Benthic Habitat Mapping Project. See <http://walrus.wr.usgs.gov/nearshorehab> for more information.

Supplemental_Information:

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.

Ran Python script, "Bathy Processor v1.5", designed to filter the bathymetry text file ****Bathy_Proc (Python Script)**** #!/usr/bin/python # Process bathymetry for P1-06-MB # Once this stabalizes, I will code into either a batch file or something more robust import os, glob, sys, time # Configure Directories SCRIPT_DIR = "E:/subx_filters" TXT_DIR = "D:/S205SC/Bathy/TXT" GRID_DIR = "D:/S205SC/Bathy/asciigrids" # Trackline Filtering Parameters MAX_SWATH_MULTIPLE = 4.0 # Trim depth samples > MAX * Water Depth (trims far-field noise) MIN_SWATH_MULTIPLE = 0.0 # Trim depth samples < MIN * Water Depth (trims nadir noise) ROLL_BEAMS = 150 # Number of beams to average to eliminate roll artifacts NOISE_BEAMS = 300 # Number of beams to average to eliminate along-track noise # Output Grid Parameters GRID_RESOLUTION = 1 # Output grid resolution SEARCH_RADIUS = GRID_RESOLUTION + 5 # Search radius for samples while gridding # Get the files for processing files = glob.glob("%s/*txt" % TXT_DIR) # Get the total size of the input files to estimate processing progress bytes_total = sum([os.path.getsize(x) for x in files]) bytes_sofar = 0 for i, file in enumerate(files): time_start = time.time() (indir, infile) = os.path.split(file) (basename, ext) = os.path.splitext(infile) print print "-------------------------------------------------------------------------" print "Begin Processing line: %s (%d of %d)" % (basename, i+1, len(files)) print if not os.path.exists(basename[0:9]): print "Step 1 of 8: converting file to binary format..." outfile = basename + ".bin" os.system('python %s/seaconvert.py -bnxzad -o %s %s' % (SCRIPT_DIR, outfile, file)) print "Step 2 of 8: trimming beams..." infile = outfile outfile = basename + ".bin.flt" os.system('python -u %s/trim.py -d%f -n%f %s > %s' % (SCRIPT_DIR, MAX_SWATH_MULTIPLE, MIN_SWATH_MULTIPLE, infile, outfile)) os.remove(infile) print "Step 3 of 8: removing roll artifacts..." infile = outfile outfile = basename + ".bin.flt.roll" os.system('python -u %s/deroll.py %s %d > %s' % (SCRIPT_DIR, infile, ROLL_BEAMS, outfile)) os.remove(infile) print "Step 4 of 8: removing system noise..." infile = outfile outfile = basename + ".bin.flt.roll.noise" os.system('python -u %s/denoise.py %s %d > %s' % (SCRIPT_DIR, infile, NOISE_BEAMS, outfile)) os.remove(infile) print "Step 5 of 8: calculate spatial extent of line..." infile = outfile outfile = basename + ".region" os.system('gmtset D_FORMAT %.2f') os.system('gmtconvert %s -bi6 -F1,2 -bo > temp1' % infile) os.system('minmax -bi2 -I%d temp1 > %s' % (GRID_RESOLUTION, outfile)) os.remove('temp1') print "Step 6 of 8: gridding line..." Rfile = basename + ".region" infile = basename + ".bin.flt.roll.noise" outfile = basename + ".nc" region = open(Rfile).readline().strip() os.system('gmtconvert %s -bi6 -F1,2,3 -bo > temp1' % (infile)) os.system('blockmean -I%d %s -C -bi3 -bo temp1 > temp2' % (GRID_RESOLUTION, region)) os.remove('temp1') os.system('nearneighbor -G%s -I%d -bi3 -N4 -R -S%d temp2' % (outfile, GRID_RESOLUTION, SEARCH_RADIUS)) os.remove('temp2') os.remove(infile) os.remove(Rfile) print "Step 7 of 8: convert line to ESRI ASCII Grid format..." infile = basename + ".nc" outfile = GRID_DIR + "/" + basename + ".asc" os.system('grdmath %s 100 MUL RINT = temp.nc' % (infile)) os.system('grd2xyz temp.nc -E > %s' % (outfile)) os.remove('temp.nc') os.remove(infile) print "Step 8 of 8: convert line to ESRI Raster format..." infile = GRID_DIR + "/" + basename + ".asc" outfile = GRID_DIR + "/" + basename #os.system('ascii2arc.py %s %s' % (infile, outfile)) os.system("ascii_to_arcraster_project_pyramids.py %s %s" % (infile, outfile)) os.remove(infile) # Calculate Estimated time remaining time_stop = time.time() if time_stop == time_start: time_stop = time_start + 1 bytes_file = os.path.getsize(file) bytes_sofar = bytes_sofar + bytes_file bytes_permin = float(bytes_file) / (time_stop - time_start) * 60.0 bytes_remaining = bytes_total - bytes_sofar time_remaining = bytes_remaining / bytes_permin percent_complete = float(bytes_sofar) / float(bytes_total) * 100 # End this line print print "Line Completed. Completed: %.0f%%, Est. Time Remaining: %.0f minutes" % (percent_complete, time_remaining) print "-------------------------------------------------------------------------" print

Ran Python script, "ascii2arc", designed to convert ASCII grids to ESRI ArcGrid fromat ****ascii2arc Script)**** # --------------------------------------------------------------------------- # ascii_to_arcraster_project_pyramids.py # Created on: Mon Oct 02 2006 01:45:01 PM # Nadine Golden # Usage: ascii2arc.py <temp1_txt> <Output_raster> # --------------------------------------------------------------------------- # Import system modules import glob, sys, string, os, win32com.client # Create the Geoprocessor object gp = win32com.client.Dispatch("esriGeoprocessing.GpDispatch.1") # Load required toolboxes... gp.SetProduct("ArcInfo") gp.AddToolbox("E:/Mapping/ArcGIS/ArcToolbox/Toolboxes/Data Management Tools.tbx") gp.AddToolbox("E:/Mapping/ArcGIS/ArcToolbox/Toolboxes/Conversion Tools.tbx") # Get script arguments... if len(sys.argv) < 3: print >> sys.stderr, "ascii_to_arcraster_project_pyramids.py: error1: not enough arguments" sys.exit(1) # Convert ascii grid to arc grid ingrid = sys.argv[1] outgrid = sys.argv[2] (tail, head) = os.path.split(ingrid) (root, ext) = os.path.splitext(head) if len(root) > 13: print >> sys.stderr, "ascii2arc.py: error 1: Grid name exceeds 13 characters: %s" % root sys.exit(1) gp.Workspace = tail gp.ScratchWorkspace = tail #print "Workspace:", gp.Workspace tmpgrid = tail + "/temp" # Check to see if temp already exists and delete it if necessary if os.path.exists(tmpgrid): gp.Delete(tmpgrid) #print "ingrid1: %s outgrid1: %s" % (ingrid, tmpgrid) gp.ASCIIToRaster_conversion(ingrid, tmpgrid, "INTEGER") # Process: Project Raster... ingrid = tmpgrid outgrid = tail + "/" + root if os.path.exists(outgrid): gp.Delete(outgrid) gp.ProjectRaster_management(ingrid, outgrid, "PROJCS['WGS_1984_UTM_Zone_10N', GEOGCS['GCS_WGS_1984', DATUM['D_WGS_1984', SPHEROID['WGS_1984',6378137.0,298.257223563]], PRIMEM['Greenwich',0.0], UNIT['Degree',0.0174532925199433]], PROJECTION['Transverse_Mercator'], PARAMETER['False_Easting',500000.0], PARAMETER['False_Northing',0.0], PARAMETER['Central_Meridian',-123.0], PARAMETER['Scale_Factor',0.9996], PARAMETER['Latitude_Of_Origin',0.0], UNIT['Meter',1.0]]; -10000 -10000 100000;0 100000;0 100000", "NEAREST", "1") # Process: Build Pyramids... gp.BuildPyramids_management(outgrid) # Clean up the mess if os.path.exists(tmpgrid): gp.Delete(tmpgrid)

chanwest_bath.txt - Sidescan sonar bathymetry image of Channel West in the Nearshore Benthic Habitat Mapping Project S. California map series.

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