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Errata - Geophysical Data Sets
Geophysical Data Sets 1000 Series
In Geophysical Data Sets 1001-1006, 1009-1028, and 1031-1034 (released June 9, 2003), the following errors were noted. In the survey reports and documentation (Microsoft Word 97 (.doc) and Adobe Acrobat (pdf formats), any and all mentions of, or references to, the digital data series identifier (i.e., Geophysical Data Set 10xx-Revised or Geophysical Data Set 10xx rev) should exclude the word "Revised" or abbreviation "rev".
GDS 1014
Ontario Airborne Geophysical Surveys, Magnetic and Electromagnetic Data; Grid and Profile Data, ASCII and Geosoft� Formats, Matachewan Area
Original Release Date: June 8, 2003
Notification Date of Data Errata: June 2, 2008
An error in the co-ordinates for the EM anomaly database (both Geosoft� binary .gdb and ASCII .csv formats) has been identified. The error affects the NAD27 UTM co-ordinates, the NAD83 UTM co-ordinates and the NAD83 geographic (longitude and latitude) co-ordinates. The error can result in the EM anomalies being plotted near the equator. The NAD27 geographic co-ordinates in the database are unaffected by this error and are correct.
The EM anomaly database, in both binary and ASCII formats, has been updated and the erroneous co-ordinate values corrected.
Corrected Files
| Path | File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|---|
| EM_anomalies_binary\ | MAANOMLY.gdb | 4,806,656 | 16/04/2008 | 1:45p |
| EM_anomalies_ASCII\ | Maanomaly.xyz | 82,969 | 16/04/2008 | 1:43p |
If you have purchased a copy of this data set where your files do
not match the file attributes shown above, please return the
original CD-ROM to Publication Sales, and a replacement copy will
be sent to you free of charge.
GDS 1053
Discover Abitibi Kirkland Lake - Larder Lake Airborne Magnetic Survey
Original Release Date: November 15, 2004
Notification Date of Data Errata: November 25, 2004
A shift in the conventionally gridded magnetic data in the eastern part of the survey (Block 2) has resulted in the following errors in the digital products:
Geophysical Data Set 1053a ASCII grids klmagnad83.gxf, klmagnad27.gxf, kl2vdnad83.gxf and kl2vdnad27.gxf are displaced 222 metres south and 16 metres west in the eastern part of the grid. Clients are advised not to use these grids and use the gradient enhanced grids instead (i.e., klmaghgnad83.gxf, klmaghgnad27.gxf, kl2vdhgnad83.gxf and kl2vdhgnad27.gxf).
Geophysical Data Set 1053b Geosoft� format binary grids klmagnad83.grd, klmagnad27.grd, kl2vdnad83.grd and kl2vdnad27.grd are displaced 222 metres south and 16 metres west in the eastern part of the grid. Clients are advised not to use these grids and use the gradient enhanced grids in their place (i.e., klmaghgnad83.grd, klmaghgnad27.grd, kl2vdhgnad83.grd and kl2vdhgnad27.grd).
Geophysical Data Sets 1100 Series
Geophysical Data Set 1100a
Ontario airborne geophysical surveys, magnetic and electromagnetic data; grid and vector data, ASCII format, Cochrane area
Original Release Date: July 20, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thcoanomaly.csv)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thcoanomaly.csv | 4,882,223 | 08/30/2000 | 08:50a |
If you have purchased a copy of this data set where your file does not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1100b
Ontario airborne geophysical surveys, magnetic and electromagnetic data; grid and vector data, Geosoft� format, Cochrane area
Original Release Date: July 20, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thcoanomaly.gdb)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thcoanomaly.gdb | 26,809,344 | 08/16/2000 | 01:41p |
If you have purchased a copy of this data set where your file does not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1100c
Ontario airborne geophysical surveys, magnetic and electromagnetic data; profile data, ASCII format, Cochrane area
Original Release Date: July 20, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thcoanomaly.csv)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Hz Profile Databases (thcochrane.xyz)
- em_bz_drift_off (15 channel array)
Original: certain channels contained incorrect EM data
Revised: the 15 channel array was replaced with the correct values - em_bz_final_on (5 channel array)
Original: certain channels contained incorrect EM data
Revised: the 5 channel array was replaced with the correct values
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thcoanomaly.csv | 4,882,223 | 08/30/2000 | 08:50a |
| thcochrane1.zip | 196,853,606 | 08/30/2000 | 04:43p |
| thcochrane2.zip | 167,860,894 | 08/31/2000 | 09:28a |
| thcochrane3.zip | 113,401,028 | 08/31/2000 | 12:06p |
| thcochrane4.zip | 118,513,585 | 08/31/2000 | 03:02p |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1100d
Ontario airborne geophysical surveys, magnetic and electromagnetic data; profile data, Geosoft� format, Cochrane area
Original Release Date: July 20, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thcoanomaly.gdb)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Hz Profile Databases (thcochrane.gdb)
- em_bz_drift_off (15 channel array)
Original: certain channels contained incorrect EM data
Revised: the 15 channel array was replaced with the correct values - em_bz_final_on (5 channel array)
Original: certain channels contained incorrect EM data
Revised: the 5 channel array was replaced with the correct values
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thcoanomaly.gdb | 26,809,344 | 08/16/2000 | 01:41p |
| thcochrane.zip | 525,932,945 | 08/16/2000 | 03:55p |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1103a
Ontario airborne geophysical surveys, magnetic and electromagnetic data; grid and vector data, ASCII format, Temagami area
Original Release Date: July 27, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thteanomaly.csv)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thteanomaly.csv | 974,505 | 09/01/2000 | 08:35a |
Notification Date of Data Errata: February 5, 2002
Keating Anomalies (THTEKC27.DXF)
An error was found in this file. The Keating anomalies were plotted using the NAD83 coordinates instead of the NAD27 coordinates, so the circles plot approximately 200 m north of the actual location.
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thtekc27.dxf | 48,960,985 | 01/25/2002 | 11:15a |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1103b
Ontario airborne geophysical surveys, magnetic and electromagnetic data; grid and vector data, Geosoft� format, Temagami area
Original Release Date: July 27, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thteanomaly.csv)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thteanomaly.gdb | 10,521,600 | 08/16/2000 | 01:42p |
Notification Date of Data Errata: February 5, 2002
Keating Anomalies (THTEKC27.DXF)
An error was found in this file. The Keating anomalies were plotted using the NAD83 coordinates instead of the NAD27 coordinates, so the circles plot approximately 200 m north of the actual location.
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thtekc27.dxf | 48,960,985 | 01/25/2002 | 11:15a |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1103c
Ontario airborne geophysical surveys, magnetic and electromagnetic data; profile data, ASCII format, Temagami area
Original Release Date: July 27, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thteanomaly.csv)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Hz Profile Databases (thtemagami.xyz)
- em_bz_drift_off (15 channel array)
Original: certain channels contained incorrect EM data
Revised: the 15 channel array was replaced with the correct values - em_bz_final_on (5 channel array)
Original: certain channels contained incorrect EM data
Revised: the 5 channel array was replaced with the correct values
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thteanomaly.csv | 974,505 | 09/01/2000 | 08:35a |
| thtemagami.zip | 295,383,447 | 09/01/2000 | 09:58a |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1103d
Ontario airborne geophysical surveys, magnetic and electromagnetic data; profile data, Geosoft� format, Temagami area
Original Release Date: July 27, 2000
Notification Date of Data Errata: September 19, 2000
The following errors were found during the QA/QC process. All of these errors occurred when our subcontractor exported the data from their in-house database into the Geosoft Inc. OASIS montajT format and subsequently into the ASCII format specified in the contract.
EM Anomaly Databases (thteanomaly.gdb)
- vert_conductance channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - depth channel
Original: anomalies that did not fit the vertical plate model were flagged with a value of -10000
Revised: flag value replaced with a dummy value (*) - line channel
Original: line numbers were truncated to three digits (e.g., 5640 became 640)
Revised: line numbers were replaced with the correct values
Hz Profile Databases (thtemagami.gdb)
- em_bz_drift_off (15 channel array)
Original: certain channels contained incorrect EM data
Revised: the 15 channel array was replaced with the correct values - em_bz_final_on (5 channel array)
Original: certain channels contained incorrect EM data
Revised: the 5 channel array was replaced with the correct values
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thteanomaly.gdb | 10,521,600 | 08/16/2000 | 01:42p |
| thtemagami.gdb | 399,549,440 | 08/16/2000 | 02:39p |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1104d
Ontario airborne geophysical surveys, magnetic and electromagnetic data; profile data, Geosoft� format, Schreiber area
Original Release Date: August 3, 2000
Notification Date of Data Errata: January 23, 2001
An error was found when trying to uncompress THSCHREIBER1.ZIP (volume 1 of 2). This file contains the raw and filtered profile data for approximately one-half the area using Geosoft Inc. OASIS montajT format, which was compressed using WinZip� 7.0.
The following error message was noted:
I/O error: unable to read from zip file
Error: invalid compressed data to inflate
Corrected File
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thschreiber1.zip | 530,398,762 | 07/31/2000 | 12:27p |
If you have purchased a copy of this data set where your file does not match the file attributes shown above and the file does not uncompress properly, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1105a
Ontario airborne geophysical surveys, magnetic and electromagnetic data; grid and vector data, ASCII format, Garden-Obonga area
Original Release Date: August 31, 2000
Notification Date of Data Errata: September 29, 2000
A problem has been discovered with the NAD83 grids provided on these data sets. All 6 grid products were projected incorrectly into the NAD83 coordinate system. This affects both the binary and the ASCII grids. The proper shift between NAD27 (NTv2 datum) and NAD83 (North American datum) is approximately +2 m in the X direction and +220 m in the Y direction. The problem grids have a shift of +140 in the X and +500 in the Y. The original NAD27 grids are correct as are the databases.
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thgo2vd83.zip | 19,365,438 | 09/25/2000 | 03:30p |
| thgodem83.zip | 15,759,623 | 09/25/2000 | 03:31p |
| thgomag83.zip | 18,526,717 | 09/25/2000 | 03:31p |
| thgoreshigh83.zip | 18,056,573 | 09/25/2000 | 03:31p |
| thgoreslow83.zip | 8,474,904 | 09/25/2000 | 03:29p |
| thgoresmid83.zip | 17,463,631 | 09/25/2000 | 03:30p |
Notification Date of Data Errata: September 29, 2000
An error was found when trying to uncompress thgopath27.zip and
thgomag27_south.zip.
These files are the flight path for the entire area and the total
field magnetic contours for the southern half (in UTM NAD27
projection) in AutoCAD� v13 DXF format, compressed using WinZip�
7.0.
The following error message was noted:
I/O error - unable to read from zip file
Error: invalid compressed data to inflate
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thgopath27.zip | 69,203,013 | 08/25/2000 | 05:03p |
| thgomag27_south.zip | 46,254,893 | 08/25/2000 | 04:59p |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1105b
Ontario airborne geophysical surveys, magnetic and electromagnetic data; grid and vector data, Geosoft� format, Garden-Obonga area
Original Release Date: August 31, 2000
Notification Date of Data Errata: September 29, 2000
A problem has been discovered with the NAD83 grids provided on these data sets. All 6 grid products were projected incorrectly into the NAD83 coordinate system. This affects both the binary and the ASCII grids. The proper shift between NAD27 (NTv2 datum) and NAD83 (North American datum) is approximately +2 m in the X direction and +220 m in the Y direction. The problem grids have a shift of +140 in the X and +500 in the Y. The original NAD27 grids are correct as are the databases.
Corrected Files
| File Name | File Size | Date Stamp | Time Stamp |
|---|---|---|---|
| thgo2vd83.GRD.gi | 3,584 | 09/22/2000 | 02:14p |
| thgo2vd83.zip | 15,045,403 | 09/25/2000 | 10:57a |
| thgodem83.GRD.gi | 3,584 | 09/22/2000 | 02:12p |
| thgodem83.zip | 13,738,096 | 09/25/2000 | 10:57a |
| thgomag83.GRD.gi | 3,584 | 09/22/2000 | 02:11p |
| thgomag83.zip | 14,936,911 | 09/25/2000 | 10:58a |
| thgoreshigh83.GRD.gi | 3,584 | 09/22/2000 | 02:08p |
| thgoreshigh83.zip | 15,090,150 | 09/25/2000 | 10:58a |
| thgoreslow83.GRD.gi | 3,584 | 09/22/2000 | 02:02p |
| thgoreslow83.zip | 6,767,934 | 09/25/2000 | 10:58a |
| thgoresmid83.GRD.gi | 3,584 | 09/22/2000 | 01:16p |
| thgoresmid83.zip | 14,227,320 | 09/25/2000 | 10:59a |
If you have purchased a copy of this data set where your files do not match the file attributes shown above, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Sets 1200 Series
Ontario Airborne Geophysical Surveys, Magnetic and Electromagnetic Data; grid and vector data, ASCII and Geosoft� formats
Original Release Date: various (see table below)
Notification Date of Data Errata: August 12, 2002
The following error was recently discovered during a detailed examination of the Operation Treasure Hunt (OTH) purchased geophysical data sets (GDS 1200 series). The original NAD27 data was improperly reprojected to NAD83. The NAD83 EASTING co-ordinates are, on average, off by approximately 5 m and the NAD83 NORTHING co-ordinates are, on average, off by approximately 241 m.
The OTH purchased data sets affected and the approximate errors in the NAD83 co-ordinate values are listed below:
| Survey Area |
GDS Data Set |
Release Date | NAD83 EASTING error (m) | NAD83 NORTHING error (m) |
|---|---|---|---|---|
| Amyot-Browning | 1200revised | 1-Aug-01 | 10 | 243 |
| Cobalt | 1201revised | 1-Aug-01 | 8 | 246 |
| Cobalt | 1201-rev1 | 6-Dec-02 | 8 | 246 |
| Gowan-Evelyn | 1202revised | 1-Aug-01 | 8 | 246 |
| Gowan-Evelyn | 1202-rev1 | 6-Dec-02 | 8 | 246 |
| Docker | 1203revised | 1-Aug-01 | -12 | 236 |
| Temagami South | 1204revised | 1-Aug-01 | 8 | 245 |
| Temagami South | 1204-rev1 | 6-Dec-02 | 8 | 245 |
| Geco-Manitouwadge | 1205 | 1-Aug-01 | 1 | 241 |
| Gitche Lake | 1206revised | 1-Aug-01 | -14 | 235 |
| Hemlo | 1207 | 1-Aug-01 | 1 | 241 |
| Kakagi Lake | 1208revised | 1-Aug-01 | -11 | 235 |
| Albany River - James Bay | 1209 | 1-Aug-01 | 2 | 239 |
| Temiskaming | 1210revised | 1-Aug-01 | 8 | 246 |
| Coral Rapids | 1213 | 11-Dec-01 | 14 | 245 |
| Kapiskau River East | 1214 | 11-Dec-01 | 17 | 236 |
| Kesagami Lake | 1215 | 11-Dec-01 | 14 | 244 |
| Melchett Lake | 1216 | 11-Dec-01 | -1 | 238 |
| Natogami Lake | 1217 | 11-Dec-01 | 13 | 244 |
| Pakwash Lake | 1218 | 11-Dec-01 | -13 | 236 |
| River Valley West | 1220 | 11-Mar-02 | 16 | 240 |
| Robb-Jamieson | 1221 | 11-Mar-02 | 8 | 245 |
| Troutlake River | 1222 | 11-Dec-01 | -17 | 237 |
| Turnbull-Godfrey | 1223 | 11-Mar-02 | 8 | 245 |
| Turnbull-Godfrey | 1223-rev | 6-Dec-02 | 8 | 245 |
The files affected include all the NAD83 grids as well as the NAD83 co-ordinate channels in the profile, EM anomaly and Keating databases. Please note that all the NAD27 co-ordinate information is correct, including all the NAD27 grids as well as the NAD27 co-ordinate channels in the profile, EM anomaly and Keating databases.
Two possible interim solutions are available to our clients requiring the NAD83 data:
- If you have the appropriate software, reproject the NAD27 data using Canada Mean or Manitoba-Ontario local datums (the difference between the two is a few metres, well within the surveys' margin of error).
- If not, "move" or shift the NAD83 grids by the values listed in the above table (positive values: move grid EAST/NORTH; negative values: move grid WEST/SOUTH) or add the values in the above table to the NAD83 coordinate channels in the profile, EM anomaly and Keating databases.
The above data sets will be corrected and re-released after all the magnetic data has been leveled to the Single Master Aeromagnetic Grid for Ontario, a project presently nearing completion. When these data sets are re-released, please return the original CD-ROM to Publication Sales, and a replacement copy will be sent to you free of charge.
Geophysical Data Set 1217-Revised: Natogami Lake Area
An error was discovered in the apparent resistivity grids for the relevelled Operation Treasure Hunt (OTH) Natogami Lake geophysical data set (Geophysical Data Set 1217-Revised) released on December 6, 2002. The error affects only the grids listed in the following table. The remaining grids as well as the profile, EM anomaly and Keating databases are correct. The apparent resistivity grid units should be in ohm-m, as indicated in the report, but are actually in log10(x) ohm-m. The following correction was applied to the apparent resistivity grids in order for the values to be in ohm-m: new grid = exp10(old grid).
Survey Area: Natogami
GDS: 1217rev
Release Date: 6-Dec-2002
| Grid File Name | Grid File Description |
|---|---|
| thnareslow27.gxf | Resistivity, coaxial, low freq |
| thnareslow83.gxf | Resistivity, coaxial, low freq |
| thnaresmid27.gxf | Resistivity, coaxial, mid freq |
| thnaresmid83.gxf | Resistivity, coaxial, mid freq |
| thnareslow27.grd | Resistivity, coaxial, low freq |
| thnareslow27.grd.gi | Resistivity, coaxial, low freq, header |
| thnareslow83.grd | Resistivity, coaxial, low freq |
| thnareslow83.grd.gi | Resistivity, coaxial, low freq, header |
| thnaresmid27.grd | Resistivity, coaxial, mid freq |
| thnaresmid27.grd.gi | Resistivity, coaxial, mid freq, header |
| thnaresmid83.grd | Resistivity, coaxial, mid freq |
| thnaresmid83.grd.gi | Resistivity, coaxial, mid freq, header |
Geophysical Data Set 1220-Revised: River Valley West Area
A minor error was also discovered in the survey report for the relevelled OTH River Valley West geophysical data set (Geophysical Data Set 1220-Revised) released on December 6, 2002. On page 47 (Profile Data), the units of measure for the apparent resistivity channels (ares_900, ares_7200 and ares_56000) should read ohm-metres instead of log10 ohm-metres.
Map Tile 60 000: Amyot-Browning total magnetic field and EM anomalies
The grid and EM anomalies are approximately 240 m south of their proper positions.
Map Tile 60 002: Amyot-Browning EM decay constant and EM anomalies
The grid and EM anomalies are approximately 240 m south of their proper positions.
Map Tile 60 197: River Valley West apparent resistivity and EM anomalies
The apparent resistivity grid and contour units should be in ohm-m, as indicated in the map legend, but are actually in ln(x)*3474 ohm-m.
The above data sets and map tiles have been corrected and are now available at our Publication Sales office. If you purchased any of the above data sets or map tiles, please return them to Publication Sales, and a replacement copy will be sent to you free of charge.