Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 7, 2006

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Distribution_Information
• Metadata_Reference_Information

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:

<https://pubs.usgs.gov/of/2009/1151/data/resistivity/raw_resis/sept7_raw.zip>

Online_Linkage: <https://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: <https://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:

<https://pubs.usgs.gov/of/2009/1151/data/resistivity/raw_resis/sept7_raw.zip>

Network_Resource_Name: <https://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