Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished material
Title: Raw CRP Data
Type_of_Source_Media: hard disk
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 20050504
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: raw crp data
Source_Contribution:
These data were acquired with an AGI SuperSting Marine system that is described at the website: www.agiusa.com/marinesystem.shtml. The particular system used for this acquisition was an 11 electrode array with electrodes spaced 5 meters apart. The potential electrodes are made of graphite, with the remaining electrodes 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 potentials 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 *.gps file. The STG file contains the resistivity data, while the GPS file contains the navigation information.
Process_Step:
Process_Description:
The data were transferred from the logging computer via AGISSAdmin software. The data files available for this day are L2F1.*, L3F1.*, L4F1.*, and L5F1.*.
Process_Date: Unknown
Process_Step:
Process_Description:
When the data were acquired, a scaling factor of 5 was used. However, because the initialization file already defined the electrodes as being 5 meters apart, this had the affect of indicating the electrodes were 25 meters apart. Therefore, Marine Log Manager was used to rescale the STG file, by using a scale factor of 0.2, to return the electrodes to the appropriate spacing.
Source_Used_Citation_Abbreviation: L1F1.stg
Process_Date: Unknown
Source_Produced_Citation_Abbreviation: L1F1_rescaled.stg
Process_Step:
Process_Description:
The data were merged with navigation and linearized using AGI's Marine Log Manager software.
Process_Date: Unknown
Process_Step:
Process_Description:
In most cases, only that portion of the linearized file that had positive distance along values was exported to the new STG file. In the case of L3F1, L4F1, and L5F1, the entire file was selected for export. These lines were run perpendicular to shore, starting at the shore. Exporting the whole line was necessary to get the nearshore values. Because of the length of one of the files, as well as incorporated turns, L2F1 is broken up and exported to 4 new STG files, and accompanying DEP files. The DEP file contains the distance along line and bathymetry values.
Process_Date: Unknown
Process_Step:
Process_Description:
The DEP files were checked for anomalous bathymetry values, and those lines within the DEP file were deleted. For L3F1, L4F1, and L5F1, the file that was exported in its entirety (which included negative distances along line), had a depth value of 0.1 assigned to the first point in the DEP file. In addition, the first distance along point in the DEP file was modified to be the same as the first point in the XYZ output of a test processing. This was done to ensure that the entire inversion had a water column constraint.
Source_Used_Citation_Abbreviation:
L2F1_part1proc.dep, L2F1_part2proc.dep, L2F1_part3proc.dep, L2F1_part4proc.dep
Process_Date: Unknown
Source_Produced_Citation_Abbreviation:
L2F1_part1proc_mod.dep, L2F1_part2proc_mod.dep, L2F1_part3proc_mod.dep, L2F1_part4proc_mod.dep
Process_Step:
Process_Description:
EarthImager software does not require that a default resistivity value for the water column be supplied in the DEP file. If one is not supplied, then it calculates a value based on the first electrode pair. For this reason, the data were processed without a value supplied (in the folder def_wres), and with a value supplied (in the folder wres). The average water resistivity value was calculated based on YSI temperature and salinity data readings recorded during the survey. The average temperature and average salinity values over the STG survey area were plugged into a JavaScript calculator to determine conductivity. The website (
http://ioc.unesco.org/oceanteacher/resourcekit/M3/Converters/SeaWaterEquationOfState/Sea%20Water%20Equation%20of%20State%20Calculator.htm) was used for this purpose. The inverse of the conductivity value was then used as the average resistivity value.
Process_Step:
Process_Description:
EarthImager version 1.9.0 was used to process the data files. The *.ini file accompanying the results contains the parameters used during the processing. These parameters include:
minimum voltage: 0.02
minimum abs(V/I): 2E-5
max repeat error: 3%
min apparent res: 0.03
max apparent res: 1000
max reciprocal error: 5%
remove spikes
smooth model inversion
finite difference method
Cholesky decomposition
Dirichlet boundary condition
thickness incremental factor: 1.1
depth factor: 1.1
number of iterations: 8
stop criteria: max RMS 3%, error reduction 5%, L2Norm
CRP processing using a 65% overlap
Process_Date: Unknown
Process_Step:
Process_Description:
The results of the processing are a JPEG image of the resistivity profile, and an XYZ file containing the distance along, depth, apparent resistivity (ohm-m). The first pass at processing (Trial1) used the default water resistivity value, while the second pass (Trial2) used the average water resistivity value in the DEP file. The JPEG file produced uses a color scale that is based on the data from this particular file.
Process_Date: Unknown
Process_Step:
Process_Description:
The XYZ output file was then loaded into Matlab, along with the depth information, to create a new JPEG image with the same color scale for all the data files. In this manner, the JPEG images can be compared directly. Care was taken to try to get the vertical and horizontal scales uniform as well, although this was not always possible due to Matlab limitations. These images reside in the Matlab images folder. Part of the filename (defwres vs wres), as well as information within the image indicates if the default water resistivity (defwres) data file was used or an average water resistivity (wres) value.
Process_Date: Unknown
Process_Step:
Process_Description:
Edits to the metadata were made to fix any errors that MP v 2.9.34 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The source information was incomplete and had to be modified to meet the standard. The process steps without process dates had the date set to unknown. The distributor information needed to be added, along with the distribution format and network resource. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.
Process_Date: 20161031
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
Process_Step:
Process_Description: USGS Thesaurus keywords added to the keyword section.
Process_Date: 20180720
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
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
Process_Step:
Process_Description: Crossref DOI link was added as the first link in the metadata.
Process_Date: 20191118
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
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
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200908
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
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
