Identification_Information: Citation: Citation_Information: Originator: John F. Bratton Originator: VeeAnn A. Cross Publication_Date: 2010 Title: Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 7, 2006 Series_Information: Series_Name: Open-File Report Issue_Identification: 2009-1151 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2009/1151/data/resistivity/raw_resis/sept7_raw.zip Online_Linkage: http://pubs.usgs.gov/of/2009/1151/html/catalog.html Larger_Work_Citation: Citation_Information: Originator: VeeAnn A. Cross Originator: David S. Foster Originator: John F. Bratton Publication_Date: 2010 Title: Continuous Resistivity Profiling and Seismic-Reflection Data Collected in 2006 from the Potomac River Estuary, Virginia and Maryland Series_Information: Series_Name: Open-File Report Issue_Identification: 2009-1151 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2009/1151/ Description: Abstract: In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on Chesapeake Bay and the Potomac River Estuary in September 2006. Chesapeake Bay resource managers are concerned about nutrients that are entering the estuary via submarine groundwater discharge, which are contributing to eutrophication. The USGS has performed many related studies in recent years to provide managers with information necessary to make informed decisions about this issue. The research carried out as part of the study described here was designed to help refine nutrient budgets for Chesapeake Bay by characterizing submarine groundwater flow and discharge of groundwater beneath part of the mainstem and a major tributary, the Potomac River Estuary. Purpose: The purpose of this dataset is to provide the raw resistivity data collected on this date by the AGI SuperSting system. In addition, these data are provided in a format ready for processing. In some cases, small edits had to be made to the original raw files to make them suitable for processing. Both the raw and modified raw files are included. And finally, this dataset acts as a data archive. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20060907 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -76.751217 East_Bounding_Coordinate: -76.453150 North_Bounding_Coordinate: 38.228350 South_Bounding_Coordinate: 38.077633 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: Field Activity Serial Number 06018 Theme_Keyword: Info Bank ID K-1-06-CH Theme_Keyword: navigation Theme_Keyword: bathymetry Theme_Keyword: Continuous Resistivity Profiling Theme_Keyword: CRP Theme_Keyword: R/V Kerhin Theme_Keyword: Lowrance GPS Theme_Keyword: AGI SuperSting Theme_Keyword: raw data Theme_Keyword: groundwater Theme_Keyword: submarine groundwater Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme_Keyword: inlandWaters Theme_Keyword: location Theme_Keyword: oceans Theme_Keyword: oceans and estuaries Theme_Keyword: oceans and coastal Theme_Keyword: geoscientificInformation Place: Place_Keyword_Thesaurus: General Place_Keyword: North America Place_Keyword: North Atlantic Place_Keyword: United States Place_Keyword: Virginia Place_Keyword: Potomac River Estuary Place_Keyword: Chesapeake Bay Place_Keyword: Dennis Point Marina Place_Keyword: Solomons, Maryland Place_Keyword: Maryland Place_Keyword: Patuxent River Access_Constraints: None. Use_Constraints: The public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: John F. Bratton Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2254 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: jbratton@usgs.gov Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.2.6.1500 Data_Quality_Information: Logical_Consistency_Report: All the data files were checked and handled in the same manner. Completeness_Report: These files represent all the raw resistivity files used to process resistivity profile data on this date. In cases where corrections had to be made to the Global Positioning System (GPS) navigation files and/or the raw resistivity files (STG), both the original and corrected files are included. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The primary navigation system used was a Lowrance 480M with an LGC-2000 Global Positioning System (GPS) antenna. The antenna was located 7.9 meters forward of the anchor point for the resistivity streamer, and approximately 3 meters forward of the fathometer transducer. These offsets were not entered into the GPS system. Additionally, because of navigation and fathometers issues, periodically the ship's navigation system was used to supplement these data. The ship had a Differential GPS (DGPS) system with the antenna placed in the same location as the Lowrance antenna. The fathometer was located (hull-mounted) roughly directly below the antenna, so no horizontal offset. Because of the mixture of systems, the accuracy is on the order of 20 meters. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: On this day most of the bathymetric values were collected by the Lowrance fathometer. This fathometer was mounted mid-ship on the starboard side of the boat. The Lowrance manufacturer indicates the speed of sound used by the system to convert to depths is 4800 feet/second. The ship's fathometer was hull mounted approximately mid-ship, relatively close to the navigation antenna. All values are assumed to be accurate to within 1 meter. Lineage: Source_Information: Source_Contribution: The continuous resistivity profile (CRP) system used on this cruise was an AGI SuperSting marine system described at the website: www.agiusa.com/marinesystem.shtml. The particular system used for this acquisition was a 100-m streamer with an 11 electrode array with electrodes spaced 10 meters apart. The source electrodes are graphite, while the receiver electrodes are stainless steel. A dipole-dipole configuration was used for the data collection in which two fixed current electrodes are assigned with the measurement of voltage potential between electrode pairs in the remaining electrodes. Each line of data acquisition records several files. The two files necessary for processing are the *.stg and the *.gps file. The STG file contains the resistivity data, while the GPS file contains the navigation information. The navigation system used in concert with the CRP system is a Lowrance LMS-480M with an LGC-2000 GPS antenna and a 200 kHz fathometer transducer. The transducer also contains a temperature sensor which was not working on Julian Day 249. Lowrance indicates the speed of sound used by the system is 4800 feet/second. On the first day of data collection (Julian Day 249, Sept. 6, 2006) the Lowrance transducer was side-mounted mid-ship on the port side of the boat. The remainder of the cruise the transducer was side-mounted mid-ship of the starboard side of the boat. The CRP system images the subsurface electrical properties of an estuarine, riverine or lacustrine environment. Resistivity differences can be attributed to subsurface geology (conductive vs less conductive layers) and hydrogeologic conditions with fresh water exhibiting high resistivity and saline conditions showing low resistivity. Process_Step: Process_Description: The data were transferred from the logging computer via AGISSAdmin software version 1.03.09. The data files available for this day are L7F1, L8F1, F9L1, F10L1, L10F2, L11F1, L12F1, L13F1, L14F1, L15F1, L16F1, L17F1, L18F1, and L19F1. These files were then transferred via a thumb drive to the processing computer. Process_Date: 2006 Process_Step: Process_Description: The first step is to check the navigation recorded in the *.gps file for each line of acquisition. I extracted the $GPRMC line from the CRP GPS files using an AWK script. (* refers to the line name, which for this day are L7F1, L8F1, F9L1, F10L1, L10F2, L11F1, L12F1, L13F1, L14F1, L15F1, L16F1, L17F1, L18F1, and L19F1). >AWK script awkit_tmp: >BEGIN { >FS="," >} >{ >FS= "," >ARGC = 2 >if ($1=="$GPRMC") { > gpstime = $2 > hr = substr($2,1,2) > min = substr($2,3,2) > sec = substr($2,5,2) > latdeg = substr($4,1,2) > latmin = substr($4,3,6) > londeg = substr($6,2,2) > lonmin = substr($6,4,6) > declat = latdeg + (latmin/60) > declon = (londeg + (lonmin/60)) * -1 > date = $10 > day = substr($10,1,2) > month = substr($10,3,2) > year = substr($10,5,2) > printf("%8.6f, %8.6f, %s:%s:%s, %s, %s\n",declon, declat, hr, min, sec, date, ARGV[2]) > } >} This AWK script was initialized by "doawk" - shell script run under CYGWIN (UNIX like environment that runs under Windows): >files=`ls *.gps | cut -d. -f1` >for file in $files >do >awk -f awkhold $file.gps $file >> resnav_jd250.txt >done Source_Used_Citation_Abbreviation: *.gps Process_Date: 2006 Source_Produced_Citation_Abbreviation: resjustnav_jd250.txt Process_Step: Process_Description: This text file (resjustnav_jd250.txt) was loaded as an event them into ArcView 3.3. Displaying these points allowed me to flag the sections of bad navigation. Source_Used_Citation_Abbreviation: resjustnav_jd250.txt Process_Date: 2006 Process_Step: Process_Description: An ANSI text file containing the ship's navigation and fathometer information was transferred from the ship's system using a thumb drive. Source_Used_Citation_Abbreviation: usgs090706.nav Process_Date: 2006 Process_Step: Process_Description: The ship's text navigation file was reformatted using an AWK script into a comma-delimited ANSI text file suitable for loading in the GIS. >AWK script "awknav": >{ >shipdate = $1 >gpstime = $2 >latdeg = substr($5,1,2) >latdecmin = $6 >declat = latdeg + (latdecmin/60) >londeg = substr($7,1,3) >londecmin = $8 >declon = -1 * (londeg + (londecmin/60)) >depmeters = $10 printf("%s, %s, %9.6f, %9.6f, %s\n",shipdate, gpstime, declat, >declon, depmeters) >} Source_Used_Citation_Abbreviation: usgs090706.nav Process_Date: 2006 Source_Produced_Citation_Abbreviation: shippnts_jd250.txt Process_Step: Process_Description: I was than able to extract each segment of reformatted ship's navigation that corresponded to the time gaps within my resistivity navigation. Source_Used_Citation_Abbreviation: shippnts_jd250.txt Process_Date: 2006 Source_Produced_Citation_Abbreviation: l7f1_gap1.txt Source_Produced_Citation_Abbreviation: l7f1_gap2.txt Source_Produced_Citation_Abbreviation: l8f1_gap1.txt Source_Produced_Citation_Abbreviation: l8f1_gap2.txt Process_Step: Process_Description: When the navigation glitched for the Lowrance, records were sent to the GPS file, but the times and fixes were bogus. Chuck Worley discovered the glitches were a result of a bad wire associated with the navigation cable. These bogus records start by recording a time of 000001 with the second record showing a time of 000006. Based on the navigation in the rest of the file which has fixes roughly every five seconds, I'm assuming that although the times themselves are bogus, the time interval in seconds is accurately represented. Based on this, I manually went through the ship's navigation segments and manually removed the records I don't need - keeping only those ship fixes that were closest in time to the fixes I believed I needed. Of course the times in the ship's navigation don't match exactly with the times I need from the Lowrance system as the ship's navigation records a fix every 3 or 4 seconds. But simply keeping the closest ship fix in time all fixes were within 1 second relative to the resistivity navigation fix I needed. The resulting files are *trim.txt (where the * refers to the initial gap files from the ship navigation). Source_Used_Citation_Abbreviation: l7f1_gap1.txt Source_Used_Citation_Abbreviation: l7f1_gap2.txt Source_Used_Citation_Abbreviation: l8f1_gap1.txt Source_Used_Citation_Abbreviation: l8f1_gap2.txt Process_Date: 2006 Source_Produced_Citation_Abbreviation: l7f1_gap1trim.txt Source_Produced_Citation_Abbreviation: l7f1_gap2trim.txt Source_Produced_Citation_Abbreviation: l8f1_gap1trim.txt Source_Produced_Citation_Abbreviation: l8f1_gap2trim.txt Process_Step: Process_Description: I use an AWK script to reformat the "trimmed" ship's navigation and write the output in the $GPRMC, $SDDPT and $SDMTW strings that the resistivity system will need. The ship system doesn't have temperature, so I used a constant value of 24.3 based on the existing temperature information from the Lowrance system. The new files are *.gps (where * refers to the trim prefix file name) >AWK script awknewgps: >BEGIN { >FS="," >} >{ >FS="," >alltime=$2 >hr=substr($2,1,2) >min=substr($2,4,2) >sec=substr($2,7,2) >month=substr($1,1,2) >day=substr($1,4,2) >yr=substr($1,9,2) >depth=$5 >declon=$4 * -1 >londeg=int(declon) >lonmin=(declon-londeg)*60 >declat=$3 >latdeg=int(declat) >latmin=(declat-latdeg)*60 >printf("$GPRMC,%s%s%s,A,%02d%06.3f,N,%03d%06.3f,W,000.0,0,%s%s%s,0,W*73\n",hr,min,sec,latdeg,latmin,londeg,lonmin,day,month,yr) >printf("$SDDPT,%s,0.0*56\n",depth) >printf("$SDMTW,24.3,C*01\n") } Source_Used_Citation_Abbreviation: l7f1_gap1trim.txt Source_Used_Citation_Abbreviation: l7f1_gap2trim.txt Source_Used_Citation_Abbreviation: l8f1_gap1trim.txt Source_Used_Citation_Abbreviation: l8f1_gap2trim.txt Process_Date: 2006 Source_Produced_Citation_Abbreviation: l7f1_gap1trim.gps Source_Produced_Citation_Abbreviation: l7f1_gap2trim.gps Source_Produced_Citation_Abbreviation: l8f1_gap1trim.gps Source_Produced_Citation_Abbreviation: l8f1_gap2trim.gps Process_Step: Process_Description: I then used VI text editor to insert these properly formatted files into the necessary sections of the resistivity navigation files that had "holidays". I also noticed that each navigation stop/start on the Lowrance system incremented the date stamp by a day. As a precaution, I copied l7f1_mod.gps to l7f1_mod2.gps before fixing this date error. Once I was confident I was fixing it correctly, in line 8 I didn't take the intermediate step. Source_Used_Citation_Abbreviation: l7f1_gap1trim.gps Source_Used_Citation_Abbreviation: l7f1_gap2trim.gps Source_Used_Citation_Abbreviation: l8f1_gap1trim.gps Source_Used_Citation_Abbreviation: l8f1_gap2trim.gps Process_Date: 2006 Source_Produced_Citation_Abbreviation: l7f1_mod2.gps Source_Produced_Citation_Abbreviation: l8f1_mod.gps Process_Step: Process_Description: The STG files that accompany these GPS files also had to be modified. As noted, each glitch in the navigation system caused the date to increment and the times to reset to 000000. I used VI to edit the dates and times in the STG files to correspond to the date and times in the GPS files. Source_Used_Citation_Abbreviation: L7F1.stg Source_Used_Citation_Abbreviation: L8F1.stg Process_Date: 2006 Source_Produced_Citation_Abbreviation: L7F1_mod.stg Source_Produced_Citation_Abbreviation: L8F1_mod.stg Process_Step: Process_Description: Two other lines had navigation gaps. These gaps were the actual absence of any information, so these lines had to be split to enable the resistivity software to process the data. Simply used Microsoft WordPad to delete the one portion of the original navigation and save the file under a new name. Source_Used_Citation_Abbreviation: L10F2.gps Source_Used_Citation_Abbreviation: L13F1.gps Process_Date: 2006 Source_Produced_Citation_Abbreviation: L10F2_part1.gps Source_Produced_Citation_Abbreviation: L10F2_part2.gps Source_Produced_Citation_Abbreviation: L13F1_part2.gps Source_Produced_Citation_Abbreviation: L13F1_part2.gps Process_Step: Process_Description: To account for the navigation gaps, the STG files of l10f2 and l13f1 also had to be split. This was done in the same manner as splitting the GPS files, where the file was brought into WordPad, the unwanted section deleted, and the file saved under a new name. Source_Used_Citation_Abbreviation: L10F2.stg Source_Used_Citation_Abbreviation: L13F1.stg Process_Date: 2006 Source_Produced_Citation_Abbreviation: L10F2_part1.stg Source_Produced_Citation_Abbreviation: L10F2_part2.stg Source_Produced_Citation_Abbreviation: L13F1_part2.stg Source_Produced_Citation_Abbreviation: L13F1_part2.stg Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 Geographic_Coordinate_Units: Degrees and decimal minutes Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Vertical_Coordinate_System_Definition: Depth_System_Definition: Depth_Datum_Name: Local surface Depth_Resolution: 0.1 Depth_Distance_Units: meters Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: John F. Bratton Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2254 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: jbratton@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: Neither the U.S. government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: WinZip Format_Version_Number: 9.0 Format_Information_Content: The WinZip file contains all the raw CRP data from Sept. 7, 2006 as well as the associated metadata files. Transfer_Size: 1.4 MB Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2009/1151/data/resistivity/raw_resis/sept7_raw.zip Network_Resource_Name: http://pubs.usgs.gov/of/2009/1151/html/catalog.html Offline_Option: Offline_Media: DVD-ROM Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: GBytes Recording_Format: UDF Fees: None. Technical_Prerequisites: The data are provided in a WinZip compressed file. The user must have software capable of uncompressing the archive. In addition, the raw data are available in a format compatible with AGI Geosciences Marine Log Manager software. The user must have software capable of reading the AGI format in order to process these data. Metadata_Reference_Information: Metadata_Date: 20100325 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2251 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile