Line, grid, and vector data, and maps for the airborne geophysical survey of the Slate Creek-Slana River Survey, Chistochina mining district, south-central Alaska

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Frequently-anticipated questions:

What does this data set describe?

Title:
Line, grid, and vector data, and maps for the airborne geophysical survey of the Slate Creek-Slana River Survey, Chistochina mining district, south-central Alaska
Abstract:
This digital publication, GPR 2009-1, contains data produced from airborne geophysical surveys conducted in 2008 for the Slate Creek-Slana River survey area in the Chistochina mining district, south-central Alaska. Aeromagnetic and electromagnetic (EM) data were acquired by helicopter for about 442 sq miles. Fugro Airborne Survey's frequency-domain DIGHEM V system was used for the EM data. GPR 2009-1 includes (1) raw and processed linedata; (2) gridded data; (3) vector files of data contours and flight lines; and (4) maps of the data.
Supplemental_Information:
The maps were compiled and drawn under contract between the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), and Stevens Exploration Management Corp. Airborne geophysical data for the area were acquired and processed by Fugro Airborne Surveys in 2008 and 2009. Index maps and page-sized color images of the gridded data are included in GPR2009-1BrowseGraphic.PDF. A future publication will include the Contractor's project report, interpretation map, and EM anomalies, as well as other files. File names for GPR 2009-1 with basic definitions and comments are given below. For further information, see the 'Entity_Attribute_Overview' and associated 'Detailed_Description' sections for each of the categories 'GRIDS', 'LINEDATA', 'VECTORS', and 'MAPS'.
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GRIDS (folder) 
 Winzip files 'GPR2009-1GridsGRD.zip' and 'GPR2009-1GridsERS.zip' each contain all grids for this publication. Unzipped file names, minus extensions, include:

 SlateCk-magigrf - Total magnetic field with IGRF removed
 SlateCk-cvg     - Calculated vertical gradient (first vertical derivative) of the total magnetic field with IGRF removed
 SlateCk-res56k  - Apparent coplanar resistivity for 56,000 (56k) Hz
 SlateCk-res7200 - Apparent coplanar resistivity for 7200 Hz
 SlateCk-res900  - Apparent coplanar resistivity for 900 Hz
 SlateCk-dtm     - Digital terrain/elevation model
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LINEDATA (folder) 
 Winzip files 'GPR2009-1LinedataXYZ.zip' and 'GPR2009-1LinedataGDB.zip' each contain the raw and processed linedata database for this publication. Unzipped file names include:

 SlateCkLinedata.txt - Supplemental text including channel names, short definition, number of decimal places, and similar items; this information is also included elsewhere in this metadata file
 SlateCkLinedata.GDB - Geosoft binary database format
 SlateCkLinedata.XYZ - Geosoft ASCII database format
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VECTORS (folder) 
 The winzip file 'GPR2009-1Vectors.zip' contains all vector files for this publication.

 SlateCk-magigrf - Contours of gridded data (total magnetic field with IGRF removed)
 SlateCk-res56k  - Contours of gridded data (56k Hz apparent coplanar resistivity)
 SlateCk-res7200 - Contours of gridded data (7200 Hz apparent coplanar resistivity)
 SlateCk-res900  - Contours of gridded data (900 Hz Apparent coplanar resistivity)
 SlateCk-fp      - Flight path
 SlateCk-SecGrid - Slightly modified Alaska PLSS Section Grid for the map areas.
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MAPS (folder) 
 Winzip files 'GPR2009-1MapsAsPDF.zip' and 'GPR2009-1MapsAsHPGL2' each contain all the maps for this publication. Map types are listed below; file names are provided in the Entity_and Attribute_Overview Section for maps and the associated Detailed_Description.

 Total magnetic field, IGRF removed ('magigrf')
 First vertical derivative of 'magigrf'
 56,000 Hz coplanar apparent resistivity
 7200 Hz coplanar apparent resistivity
 900 Hz coplanar apparent resistivity
  1. How should this data set be cited?

    Burns, L.E., Fugro Airborne Surveys Corp., and Stevens Exploration Management Corp., 2009, Line, grid, and vector data, and maps for the airborne geophysical survey of the Slate Creek-Slana River Survey, Chistochina mining district, south-central Alaska: Geophysical Report GPR 2009-1, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 DVD

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -145.14
    East_Bounding_Coordinate: -143.78
    North_Bounding_Coordinate: 63.24
    South_Bounding_Coordinate: 62.75

  3. What does it look like?

    GPR2009-1BrowseGraphic.pdf (PDF)
    GPR2009-1BrowseGraphic.pdf contains 
     Figure 1. General location of the survey area within Alaska.
 Figure 2. Location of the survey area showing 1:63,360-scale map sheet locations, towns, and roads.
 Figure 3. Total magnetic field, IGRF removed
 Figure 4. First vertical derivative of the total magnetic field, IGRF removed
 Figure 5. 56,000 Hz coplanar apparent resistivity
 Figure 6. 7200 Hz coplanar apparent resistivity
 Figure 7. 900 Hz coplanar apparent resistivity
 Figure 8. Digital elevation model

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: Sep-2008
    Ending_Date: Mar-2009
    Currentness_Reference: publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form:
    raster digital data, tabular digital data, vector digital data, and atlas

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 6
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -147
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 25
      Ordinates (y-coordinates) are specified to the nearest 25
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Raw and processed linedata are provided in Geosoft binary (GDB) database format ('GPR2009-1LinedataGDB.zip') and in Geosoft ASCII (XYZ) ('GPR2009-1LinedataXYZ.zip') format. SlateCkLinedata.txt includes information included in this metadata document, but may be easier to read than the metadata document. SlateCkLinedata.txt is included with each downloadable zip file.
    Entity_and_Attribute_Detail_Citation:
    L.E. Burns, Division of Geological & Geophysical Surveys and Fugro Airborne Surveys
    SlateCkLinedata.GDB and SlateCkLinedata.XYZ
    Linedata containing raw and processed linedata, and related calculated fields. Attributes below pertain to both SlateCkLinedata.gdb and SlateCkLinedata.xyz. Information contained in the ID cell, described below for the GDB version, is included in the XYZ file in Geosoft ASCII XYZ format as lines or columns. (Source: Fugro Airborne Surveys & L.E. Burns)

    ID CELL
    The ID Cell in the Geosoft GDB database, in format 'X43219:BNFN', provides five pieces of information at a minimum. The line type, and basic line number and associated flight segment are given on the left side of the colon; the EM bird identification and flight number are given to the right of the colon. The EM bird identification and flight number are also in the separate channel 'FLIGHT' and are described below in the attribute 'FLIGHT'. (Source: Fugro Airborne Surveys, L.E. Burns, and Geosoft)

    The line type, and the basic line number and associated flight segment are in the format of 'X43210'.
    -------------------------------------------------------------
    1. 'X' = Line Type where: 

    > L for normal (traverse) lines; oriented nominally NW-SE (350 degrees).
> T for tie and border (boundary) lines; tie lines oriented nominally NE-SW (80 degrees); border lines occur around the outline border where traverse or tie lines are not parallel to the outline.
    -------------------------------------------------------------
    2. '43210' represents the basic line number, designated before flying, and always ends in a multiple of '10'. In general, the traverse lines increase by 10 from west to east, e.g. 10040, 10050, 10060; the tie lines increase by 10 from north to south; and the border lines increase by 10 in general from northwest to southeast. Line numbers used in this project include: 
    > a. Traverse lines 10010 (west) to 11510 (east);
> b. Tie lines 19010 (north) to 19130 (south);
> c. Boundary lines 19140 (northwest) to 19570 (southeast).
    -------------------------------------------------------------
    3. The fifth digit in '43210' represents the flight segment along a single traverse, tie, or border line. The fifth digit for the initial flight segment is '0', and is increased by '1' for each successive flight segment along the line, e.g., 10040, 10041, 10042, 10043. Numerous flight segments along a line are often required because of long line length, weather, refueling, active diurnal, other 'out-of-spec' data, and other items. The flight segments along a line may be in any spatial order, and may not have the same flight number (FN).

    X
    easting NAD 27 (UTM Zone 6) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:593502.37
    Maximum:664271.79
    Units:m
    Resolution:0.01

    Y
    northing NAD 27 (UTM Zone 6) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:6961570.98
    Maximum:7013846.19
    Units:m
    Resolution:0.01

    FID
    Fiducial; the time in tenths of seconds from the start to the end of the particular flight. Sampling typically occurred at each fiducial for almost all items in the database. (Source: Fugro Airborne Surveys)

    The attribute measurement resolution is 0.1 second. The values increase from the beginning of a flight to the end. Only FIDS during production flights are included in the database.

    LATITUDE
    latitude WGS 84 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-145.1434951
    Maximum:-143.7800693
    Units:degrees
    Resolution:0.0000001

    LONGITUDE
    longitude WGS 84 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:62.754901
    Maximum:63.2422932
    Units:degrees
    Resolution:0.0000001

    FLIGHT
    First two digits are Fugro's EM bird identification number for the bird used for this job, i.e., '16'. The last three digits represent the flight numbers associated with this project. A flight number is the number of the helicopter flight from home base to home base associated with this project. The flights are numbered from the beginning of the project to the end. Only those flight numbers containing acquisition of final data measurements are included in the database. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:16002
    Maximum:16034
    Units:flight
    Resolution:1

    DATE
    range of flight dates (mm/dd/yyyy) for production flights (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:09/15/2008
    Maximum:10/11/2008
    Units:day
    Resolution:1

    ALTRAD_BIRD
    calculated bird height above surface from radar altimeter (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-18.21
    Maximum:294.76
    Units:m
    Resolution:0.3

    GPSZ
    bird height above spheroid. The GPSZ (or GPS-Z) value is primarily dependent on the number of available satellites. Although post-processing of GPS data will yield X and Y accuracies on the order of 1 meter, the accuracy of the Z value is usually much less, sometimes in the +/-20 meter range (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:792.60
    Maximum:2360.20
    Units:m
    Resolution:0.01

    DTM
    Digital terrain/elevation model (above WGS 84 datum); data in m. Elevation calculation used for the digital elevation model is directly dependent on the accuracy of the two input parameters, ALTRAD_BIRD and GPSZ. The ALTRAD_BIRD value may be erroneous in areas of heavy tree cover, where the altimeter reflects the distance to the tree canopy rather than the ground. The GPSZ (or GPS-Z) value described above the accuracy of the Z value is usually much less, sometimes in the +/-20 meter range. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:717.32
    Maximum:2201.89
    Units:m
    Resolution:0.01

    DIURNAL_FILT
    measured diurnal ground magnetic intensity; measured every 1.0 second (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:56593.577
    Maximum:56681.796
    Units:nT
    Resolution:0.01

    DIURNAL_COR
    diurnal correction - base removed (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-57.324
    Maximum:30.896
    Units:nT
    Resolution:0.01

    MAG_RAW
    total magnetic field - spike rejected (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55055.66
    Maximum:73302.52
    Units:nT
    Resolution:0.01

    MAG_LAG
    total magnetic field - corrected for lag (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55055.66
    Maximum:73302.52
    Units:nT
    Resolution:0.01

    MAG_DIU
    total magnetic field - diurnal variation removed (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55054.20
    Maximum:73294.98
    Units:nT
    Resolution:0.01

    IGRF
    international geomagnetic reference field for location and date (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:56834.09
    Maximum:56937.79
    Units:nT
    Resolution:0.01

    MAG_RMI
    residual magnetic intensity - IGRF removed, then leveled - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1850.22
    Maximum:16449.20
    Units:nT
    Resolution:0.01

    MAGIGRF
    mag_rmi with constant added back - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55031.78
    Maximum:73331.20
    Units:nT
    Resolution:0.01

    CPI900_FILT
    900 Hz horizontal coplanar coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2132.01
    Maximum:166.22
    Units:ppm
    Resolution:0.12

    CPQ900_FILT
    900 Hz horizontal coplanar coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.69
    Maximum:279.69
    Units:ppm
    Resolution:0.12

    CXI1000_FILT
    1000 Hz vertical coaxial coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-507.33
    Maximum:66.65
    Units:ppm
    Resolution:0.06

    CXQ1000_FILT
    11000 Hz vertical coaxial coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-4.96
    Maximum:79.53
    Units:ppm
    Resolution:0.06

    CXI5500_FILT
    5500 Hz vertical coaxial coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-502.13
    Maximum:152.32
    Units:ppm
    Resolution:0.12

    CXQ5500_FILT
    5500 Hz vertical coaxial coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-11.95
    Maximum:182.01
    Units:ppm
    Resolution:0.12

    CPI7200_FILT
    7200 Hz horizontal coplanar coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1847.95
    Maximum:664.94
    Units:ppm
    Resolution:0.24

    CPQ7200_FILT
    7200 Hz horizontal coplanar coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.86
    Maximum:732.99
    Units:ppm
    Resolution:0.24

    CPI56K_FILT
    56 kHz horizontal coplanar coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1869.29
    Maximum:1382.69
    Units:ppm
    Resolution:0.60

    CPQ56K_FILT
    56 kHz horizontal coplanar coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-10.90
    Maximum:1765.53
    Units:ppm
    Resolution:0.60

    CPI900
    900 Hz horizontal coplanar coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2132.01
    Maximum:163.29
    Units:ppm
    Resolution:0.12

    CPQ900
    900 Hz horizontal coplanar coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.23
    Maximum:279.69
    Units:ppm
    Resolution:0.12

    CXI1000
    1000 Hz vertical coaxial coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-507.07
    Maximum:66.6
    Units:ppm
    Resolution:0.06

    CXQ1000
    1000 Hz vertical coaxial coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.78
    Maximum:79.53
    Units:ppm
    Resolution:0.06

    CXI5500
    5500 Hz vertical coaxial coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-502.13
    Maximum:152.15
    Units:ppm
    Resolution:0.12

    CXQ5500
    5500 Hz vertical coaxial coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-4.01
    Maximum:182.01
    Units:ppm
    Resolution:0.12

    CPI7200
    7200 Hz horizontal coplanar coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1847.95
    Maximum:665.52
    Units:ppm
    Resolution:0.24

    CPQ7200
    7200 Hz horizontal coplanar coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-0.63
    Maximum:732.99
    Units:ppm
    Resolution:0.24

    CPI56k
    56 kHz horizontal coplanar coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1869.29
    Maximum:1384.18
    Units:ppm
    Resolution:0.60

    CPQ56k
    56 kHz horizontal coplanar coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:1.22
    Maximum:1765.53
    Units:ppm
    Resolution:0.60

    RES900
    apparent resistivity - 900 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:7.98
    Maximum:1325.00
    Units:ohm-m
    Resolution:0.1

    RES7200
    apparent resistivity - 7200 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:12.83
    Maximum:10750.00
    Units:ohm-m
    Resolution:0.24

    RES56K
    apparent resistivity - 56 kHz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:5.2
    Maximum:60000.00
    Units:ohm-m
    Resolution:0.01

    DEP900
    apparent depth - 900 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-150.33
    Maximum:227.86
    Units:m
    Resolution:0.01

    DEP7200
    apparent depth - 7200 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-156.07
    Maximum:115.02
    Units:m
    Resolution:0.1

    DEP56K
    apparent depth - 56 kHz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-172.82
    Maximum:77.69
    Units:m
    Resolution:0.1

    DIFI
    difference function in-phase; based on CXI5500 & CPI7200 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-159.468
    Maximum:152.317
    Units:unitless
    Resolution:0.1

    DIFQ
    difference function quadrature; based on CXQ5500 & CPQ7200 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-35.594
    Maximum:59.620
    Units:unitless
    Resolution:0.1

    CPPL
    coplanar powerline monitor (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.0000122
    Maximum:0.0011785
    Units:unitless
    Resolution:0.0000001

    CXSP
    coaxial spherics monitor (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.0000001
    Maximum:0.0012683
    Units:unitless
    Resolution:0.0000001

    CPSP
    coplanar spherics monitor (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.0002033
    Maximum:0.0030306
    Units:unitless
    Resolution:0.0000001

    GPR2009-1GridsGRD.zip and GPR2009-1ERS.zip
    The zip files contain the six grids and supporting files for this publication in either Geosoft binary float (GRD) format or ER Mapper (ERS) format. Each grid is in NAD 27 datum, UTM 6N, and has 25m cell size with x and y in meters. Grid files are listed below as attributes. Two supporting files, a Geosoft projection file (GI) and a Geosoft v7-produced metadata file (XML), are included for each Geosoft grid file. The Geosoft grid is viewable (or importable into other software) without using these supported files. When using Geosoft, the GI file automatically sets the projection of the grid is the GI file is placed in the same directory as the grid file (GRD). Setting the projection can also be done manually in Geosoft without the GI file. Each ER Mapper grid consists of two files, a header (projection) file (.ERS) and a data file (no extension). Both ER Mapper files are necessary to view a grid or to convert it to another software format. (Source: Fugro Airborne Surveys)

    SlateCk-magigrf
    Total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    grid file; magnetic value in nanoTeslas (nT)

    SlateCk-cvg
    Calculated vertical gradient (first vertical derivative 'dz') of the total magnetic field with IGRF removed; dz in nT/m. (Source: Fugro Airborne Surveys)

    grid file; dz in nT/m

    SlateCk-res56k
    Apparent coplanar resistivity for 56,000 (56k) Hz. calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    grid file; apparent resistivity in ohm-m

    SlateCk-res7200
    Apparent coplanar resistivity for 7200 Hz. calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    grid file; apparent resistivity in ohm-m

    SlateCk-res900
    Apparent coplanar resistivity for 900 Hz. calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    grid file; apparent resistivity in ohm-m

    SlateCk-dtm
    Digital elevation/terrain model; elevation in m. (Source: Fugro Airborne Surveys)

    grid file; elevation in meters

    Entity_and_Attribute_Overview:
    Six vector files are included in 'GPR2009-1Vectors.zip' in Autocad DXF format, v2000. Four of the files (SlateCk-magigrf.dxf, SlateCk-res56k.dxf, SlateCk-res7200.dxf, and SlateCk-res900.dxf) contain data contours produced from the data grids 'SlateCk-magigrf.grd', 'SlateCk-res56k.grd', 'SlateCk-res7200.grd', and 'SlateCk-res900.grd', and appear respectively on maps 2a,b, 5a,b, 7a,b, and 9a,b. 'SlateCk-fp' contains all flight lines of the survey, does not occur on any of the current maps, but is provided for use as overlays. 'SlateCk-SecGrid.dxf' contains thin section grid lines, thicker township and ranges lines, township and range labels, and map borders. This file is used for orientation purposes on maps that do not have topographic contour lines, and instead have geophysical data contour lines - maps 2a,b, 5a,b, 7a,b, and 9a,b. To produce this file, the Alaska PLSS Section Grid shapefile (<ftp://ftp.dnr.state.ak.us/asgdc/adnr/pls_section.zip>) was downloaded on 1/12/09 from the Alaska Department of Natural Resources - Land Records Information Section. The shapefile was converted to a MapInfo TAB file, reprojected from NAD83 to NAD27 UTM Zone 6, and cut to fit the survey area using MapInfo Professional v9.0. The file was verified to project correctly with the corresponding USGS DRG topographic map. The file was further modified by Fugro Airborne Surveys using AutoCad, who changed the township and range line widths and colors, and added township and range labels. Note that though the flight path labeling and township and range labels on files 'SlateCk-fp ' and 'SlateCk-SecGrid' import correctly in Geosoft v 6.4, the labels are shifted to the left in Geosoft v 7.0 and MapInfo v 9.0 and v 9.0.2. Other software may also be affected as well. Though not ideal in terms of software compatibility, DXF 2000 is the best format we could achieve at this time with current software. Importing the flight path in Autocad v. 13, the format used for geophysical publications since 1994, into MapInfo v 8.5 produced more than 7,000 TAB files instead of the typical 4 or 5, and was not practical. Similar problems occurred with the section grid file. The contour numbers given in the data contour files are vectors, not text, and are thus not affected.
    Entity_and_Attribute_Detail_Citation:
    L.E. Burns, Division of Geological & Geophysical Surveys and Fugro Airborne Surveys
    GPR2009-1Vectors.zip
    Zip file contains all vectors for this publication in Autocad DXF v2000 format. Data contours were produced for the grid images shown on the maps. (Source: Fugro Airborne Surveys)

    SlateCk-magigrf
    Total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    vector file containing lines and vector 'numbers'

    SlateCk-res56k
    Apparent coplanar resistivity for 56,000 (56k) Hz; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    vector file containing lines and vector 'numbers'

    SlateCk-res7200
    Apparent coplanar resistivity for 7200 Hz; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    vector file containing lines and vector 'numbers'

    SlateCk-res900
    Apparent coplanar resistivity for 900 Hz; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    vector file containing lines and vector 'numbers'

    SlateCk-fp
    Flight path containing lines and flight numbers. See the vector 'Overview_Description' section above for potential text offset of the flight numbers due to current software incompatibilities. See the ID cell description in 'Detail_Description' for 'Linedata' for information about flight line type, numbers, and flight directions. (Source: Fugro Airborne Surveys)

    vector file containing lines and text

    SlateCk-SecGrid
    Alaska PLSS Section Grid (original file name 'pls_section') for the map areas; converted to NAD 27, UTM zone 6N, and modified by Fugro Airborne Surveys for line width, color, township and range numbers for the maps, and map borders. See the vector 'Overview_Description' section above for potential text problems with township and range text offset due to current software incompatibilities. (Source: Alaska Department of Natural Resources - Land Records Information Section; L.E. Burns, Division of Geological & Geophysical Surveys; and Fugro Airborne Surveys)

    vector file containing lines and text

    Entity_and_Attribute_Overview:
    Maps are provided in PDF and HPGL/2 format. The HPGL/2 files have brighter colors and sharper topography than the Adobe Acrobat files. See 'Technical_Prerequisites' section for more information on printing maps. Two map sheets, labeled 'A' and 'B', are needed to cover the survey area at a scale of 1:63,360 (inch-to-a-mile) for each map type. Bounding coordinates for the sheets are given immediately below. 'A' maps - Part Mt. Hayes Quadrangle West, -145.17 East, -144.00 North, 63.25 South, 63.00 'B' maps - Parts of Gulkana and Nabesna quadrangles West, -144.50 East, -143.75 North, 63.00 South, 62.75 GPR 2009-1 includes the 18 publications (maps) below. 
      GPR 2009-1-1A.  Total magnetic field of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle: 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-1B.  Total magnetic field of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-2A.  Total magnetic field of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, magnetic contours included.
  GPR 2009-1-2B.  Total magnetic field of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, magnetic contours included.
  GPR 2009-1-3A.  First vertical derivative of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-3B.  First vertical derivative of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-4A.  56,000 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-4B.  56,000 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-5A.  56,000 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, 56,000 Hz apparent resistivity contours included.
  GPR 2009-1-5B.  56,000 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, 56,000 Hz apparent resistivity contours included.
  GPR 2009-1-6A.  7200 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-6B.  7200 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-7A.  7200 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, 7200 Hz apparent resistivity contours included.
  GPR 2009-1-7B.  7200 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, 7200 Hz apparent resistivity contours included.
  GPR 2009-1-8A.  900 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, Includes topography
  GPR 2009-1-8B.  900 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, topography included.
  GPR 2009-1-9A.  900 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, part of Mt. Hayes Quadrangle; 1 sheet, scale 1:63,360, 900 Hz apparent resistivity contours included.
  GPR 2009-1-9B.  900 Hz coplanar apparent resistivity of the Slate Creek - Slana River area, Chistochina mining district, southcentral Alaska, parts of Gulkana and Nabesna quadrangles; 1 sheet, scale 1:63,360, 900 Hz apparent resistivity contours included.
    Entity_and_Attribute_Detail_Citation:
    L.E. Burns, Division of Geological & Geophysical Surveys, and Fugro Airborne Surveys
    GPR2009-1MapsAsPDF.zip and GPR2009-1MapsAsHPGL2.zip
    Each zip file contains all maps for this publication. File names ending in 'A' show data for the survey area north of 63 degrees N latitude (part of the Mt. Hayes quadrangle). File names ending in 'B' show data for the area south of 63 degrees N latitude (parts of the Gulkana and Nabesna quadrangles). (Source: Fugro Airborne Surveys)

    GPR2009-1-1A
    Northern map of the total magnetic field with IGRF removed; topography included. A constant has been added to the IGRF-removed residual magnetics to produce a total magnetic field value, IGRF-removed; magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-1B
    Southern map of the total magnetic field with IGRF removed; topography included. A constant has been added to the IGRF-removed residual magnetics to produce a total magnetic field value, IGRF-removed; magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-2A
    Northern map of the total magnetic field with IGRF removed; magnetic contours included. A constant has been added to the IGRF-removed residual magnetics to produce a total magnetic field value, IGRF-removed; magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-2B
    Southern map of the total magnetic field with IGRF removed; magnetic contours included. A constant has been added to the IGRF-removed residual magnetics to produce a total magnetic field value, IGRF-removed; magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-3A
    Northern map of the first vertical derivative of the total magnetic field with IGRF removed; topography included; nT/m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-3B
    Southern map of the first vertical derivative of the total magnetic field with IGRF removed; topography included; nT/m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-4A
    Northern map of the 56,000 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; topography included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-4B
    Southern map of the 56,000 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; topography included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-5A
    Northern map of the 56,000 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; apparent resistivity contours included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-5B
    Southern map of the 56,000 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; apparent resistivity contours included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-6A
    Northern map of the 7200 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; topography included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-6B
    Southern map of the 7200 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; topography included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-7A
    Northern map of the 7200 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; apparent resistivity contours included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-7B
    Southern map of the 7200 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; apparent resistivity contours included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-8A
    Northern map of the 900 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; topography included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-8B
    Southern map of the 900 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; topography included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-9A
    Northern map of the 900 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; apparent resistivity contours included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2009-1-9B
    Southern map of the 900 coplanar apparent resistivity, calculated using a pseudo-layer half-space model; apparent resistivity contours included; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Funding was provided by the Alaska State Legislature as part of the DGGS Airborne Geophysical/Geological Mineral Inventory (AGGMI) program.

  3. To whom should users address questions about the data?

Why was the data set created?

The survey was part of the Alaska Airborne Geophysical/Geological Mineral Inventory project funded by the Alaska State Legislature and managed by State of Alaska, Department of Natural Resources (DNR), Division of Geological & Geophysical Surveys (DGGS). The project seeks to catalyze private-sector mineral development investment. The project delineates mineral zones on Alaska state lands that: 1) have major economic value; 2) can be developed in the short term to provide high quality jobs for Alaska; and 3) will provide economic diversification to help offset the loss of Prudhoe Bay oil revenue.

How was the data set created?

  1. From what previous works were the data drawn?

    Akima, 1970 (source 1 of 1)
    Akima, H., 1970, A new method of interpolation and smooth curve fitting based on local procedures: Journal of the Association of Computing Machinery v. 7, no. 4.

    Online Links:

    • None

    Type_of_Source_Media: paper
    Source_Contribution:
    Fugro Airborne Surveys used a modification of this method while making grids.

  2. How were the data generated, processed, and modified?

    Date: 2008 (process 1 of 5)
    The airborne geophysical data were acquired with a DIGHEM(V) Electromagnetic (EM) system and a Fugro D1344 cesium magnetometer with a Scintrex CS3 cesium censor. Data were acquired between Sept. 15th and Oct. 11th 2008. The EM and magnetic sensors were flown at a height of 100 feet. In addition, the survey recorded data from a radar altimeter, GPS navigation system, 50/60 Hz monitors, and video camera. Flights were performed with an AS350B-3 Squirrel helicopter at a mean terrain clearance of 200 feet along N350E survey flight lines with one-quarter mile line spacing. Tie lines were flown perpendicular to the flight lines at intervals of approximately 3 miles. A Novatel OEM4 Global Positioning System was used for navigation and flight path recovery. The helicopter position was derived every 0.5 seconds (2 Hz); the ground GPS base station data were collected at 0.1 second (10 Hz) intervals. The use of the differentially-corrected base station data results in a positional accuracy of better than one meter. The positional xy data are interpolated from 2 Hz to 10 Hz. Flight path positions were projected onto the Clarke 1866 (UTM zone 6) spheroid, 1927 North American datum using a central meridian (CM) of 147 degrees, a north constant of 0 and an east constant of 500,000.

    Date: 2009 (process 2 of 5)
    The total magnetic field data were acquired with a sampling interval of 0.1 seconds, and were (1) corrected for measured system lag, (2) corrected for diurnal variations by subtraction of the digitally recorded base station magnetic data (linedata field 'mag_diu'), (3) adjusted for regional variations using date of flight and altimeter-adjusted IGRF, (4) leveled to the tie line data resulting in the final residual magnetic intensity (linedata field 'mag_rmi'), (5) increased by a constant of 56,882 to provide an IGRF-corrected total magnetic field column (linedata field 'mag_igrf') and (6) interpolated onto a regular 80-m grid using a modified Akima (1970) technique. The total magnetic field data were subjected to a processing algorithm that enhances the response of magnetic bodies in the upper 500 m and attenuates the response of deeper bodies. The resulting (calculated) vertical gradient grid ('SlateCk-cvg') provides better definition and resolution of near-surface magnetic units. It also identifies weak magnetic features that may not be evident in the total field data. All magnetic grids were then resampled from the 80-m cell size down to a 25-m cell size using a modified Akima (1970) technique to produce the maps and final grids contained in this publication.

    Data sources used in this process:

    • Akima, 1970

    Date: 2009 (process 3 of 5)
    The DIGHEM V EM system measured inphase and quadrature components at five frequencies. Two vertical coaxial-coil pairs operated at 1121 (1000) and 5491 (5500) Hz while three horizontal coplanar-coil pairs operated at 877 (900), 7116 (7200), and 55,900 (56,000) Hz. The EM data were sampled at 0.1 second intervals. The EM system responds to bedrock conductors, conductive overburden, and cultural sources. The EM inphase and quadrature data were drift corrected using base level data collected at high altitude (areas of no signal). Along-line filters are applied to the data to remove spheric spikes. The data were inspected for variations in phase, and a phase correction was applied to the data if necessary. Apparent resistivities were then calculated from the inphase and quadrature data for all frequencies based on a pseudo-layer half-space model. Manual leveling of the inphase and quadrature of each coil pair, based on the resistivity data and comparisons to the data from the other frequencies, was performed. Automated micro-leveling is carried out in areas of low signal. The EM data were interpolated onto a regular 80-m grid using a modified Akima (1970) technique. The resulting grids were subjected to a 3x3 Hanning filter and resampled to a 25-m cell size before contouring and map production.

    Data sources used in this process:

    • Akima, 1970

    Date: 2009 (process 4 of 5)
    To produce the digital elevation/terrain model, the GPS-Z data were differentially corrected (GPSZ), and the ALTRAD_BIRD data were filtered using a 13 median filter, followed by a 13 Hanning filter. Both the GPSZ and ALTRAD_BIRD data were then checked for spikes, which were removed manually. The corrected altimeter was then subtracted from the GPSZ data to produce profiles of the height above mean sea level along the survey lines. The data were manually leveled to remove any errors between lines. After all leveling, the data were DC shifted to match the local maps, in this case, NAD27. The 80-m DEM grid was then resampled to a 25-m cell size to produce the DEM grid contained in this publication.

    Date: 2009 (process 5 of 5)
    The HPGL2 files were created with HP Designjet 5000 printer driver v5.32 and plot on some plotters, but not all plotters correctly. The Adobe Acrobat format files were created with Adobe Acrobat Distiller 9.0 from Postscript files.

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    Geophysical data were acquired during an airborne survey. The magnetometer used had a sensitivity of 0.01 nT. Resistivity sensitivity varies among the different frequencies from 0.06 ppm to 0.30 ppm. Survey contracts specified the conditions and specifications under which these data were collected. Altimeter, heading, lag, and frequent EM calibrations were done. More information will be available in the project report to be published fall 2009.

  2. How accurate are the geographic locations?

    The helicopter position was derived every 0.5 seconds using post-flight differential positioning to an accuracy of better than 1 m.

  3. How accurate are the heights or depths?

    The radar altimeter ('ALTRAD_BIRD') had a stated resolution of 0.3 meter, and an accuracy better than 10% of the flying height, i.e. better or equal to 3 meters for this survey. The ALTRAD_BIRD value may be erroneous in areas of heavy tree cover, where the altimeter reflects the distance to the tree canopy rather than the ground.

  4. Where are the gaps in the data? What is missing?

    The database includes files that contain raw and processed aeromagnetic electromagnetic, altimetry, and locational data for the survey area. Areas with no data for a given channel are flagged with the dummy variable (*). These represent 1) sampling differences, e.g., most sampling was 10 samples per second, but the diurnal_filt channel was sampled once per second; 2) magnetic lag shift at the end of a line, and spikes and dropouts in the magnetic reading; and 3) resistivity and depth values that are not calculated because flying height was too high to produce meaningful calculations. The linedata file includes 48 channels (not including flight line number) for each of the 221 flight lines. A total of 1,357090 data locations are included. The channels are listed below showing number of data points filled with data and those filled with dummies. 

    -------------------------------------------------------------
    
Channel          # of           # of
Name              Points         Dummies
X                1357090           0
Y                1357090           0
fid              1357090           0
latitude         1357090           0
longitude        1357090           0
flight           1357090           0
date             1357090           0
altrad_bird      1357090           0
gpsz             1357090           0
dtm              1357090           0
diurnal_cor      1357090           0
igrf             1357090           0
cpi900_filt      1357090           0
cpq900_filt      1357090           0
cxi1000_filt     1357090           0
cxq1000_filt     1357090           0
cxi5500_filt     1357090           0
cxq5500_filt     1357090           0
cpi7200_filt     1357090           0
cpq7200_filt     1357090           0
cpi56k_filt      1357090           0
cpq56k_filt      1357090           0
cpi900           1357090           0
cpq900           1357090           0
cxi1000          1357090           0
cxq1000          1357090           0
cxi5500          1357090           0
cxq5500          1357090           0
cpi7200          1357090           0
cpq7200          1357090           0
cpi56k           1357090           0
cpq56k           1357090           0
difi             1357090           0
difq             1357090           0
cxsp             1357088           2
cpsp             1357087           3
mag_raw          1357086           4
cppl             1357070          20
res900           1355845        1245
res7200          1355845        1245
res56k           1355845        1245
mag_lag          1353108        3982
mag_diu          1353108        3982
mag_rmi          1353108        3982
magigrf          1353108        3982
dep56k           1298859       58231
dep7200          1141195      215895
dep900            458759      898331
diurnal_filt      135706     1221384
    Except for the 4 missing mag_raw values, the missing mag_lag, mag_diu, mar_rmi, and magigrf are due to lag correction; these locations are outside of the contracted survey bounds. Missing values in the apparent resistivity (res56k, res7200, and res900) and associated calculated 'depth' (dep56k, dep7200, and dep900) are due to calculations being meaningless, generally caused by increase in altitude.

  5. How consistent are the relationships among the observations, including topology?

    Data for this survey were collected by a single subcontractor (Fugro Airborne Surveys) who was responsible for collecting and processing the data. All the data were collected with the same instruments (magnetometers, electromagnetic bird and sensors, altimeters, and navigational system). Fugro's internal project reference number for the Slate Creek-Slana River survey is '08046'and their internal media reference number for this publication (v 1.0) is 'CDVD00387'.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints:
This report, map and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Use_Constraints:
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS).

  1. Who distributes the data set? (Distributor 1 of 1)

    State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS)
    Natural Resource Technician
    3354 College Road
    Fairbanks, AK 99709-3707
    USA

    907-451-5020 (voice)
    907-451-5050 (FAX)
    dggspubs@alaska.gov

    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our Web site (<http://www.dggs.alaska.gov>) for the latest information on available data. Please contact us using the e-mail address above whenever possible.
  2. What's the catalog number I need to order this data set?

    Geophysical Report 2009-1

  3. What legal disclaimers am I supposed to read?

    The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Custom views or processing may be requested. Please contact Laurel Burns by phone (907-451-5021), e-mail (laurel.burns@alaska.gov), or fax (907-451-5050) to discuss custom processing availability, fees, and turnaround time.

  6. What hardware or software do I need in order to use the data set?

    Software with ability to use, import, or convert Geosoft float GRD, binary GDB, and ASCII XYZ files, Autocad DXF files, Adobe Acrobat PDF, and text files. Free downloadable interfaces for converting the gridded and dxf files are available at the Geosoft Web site (<http://www.geosoft.com>; Oasis Montaj viewer), and the ER Mapper Web site (<http://www.ermapper.com>). Freeware software 'printfile' (<http://www.lerup.com/printfile/>) prints HPGL/2 files easily on compatible printers. The HPGL/2 files have brighter colors and sharper topography than the PDF maps. Maps are viewable digitally only with the PDF format, and of course may also be printed.

Who wrote the metadata?

Dates:
Last modified: 09-Jun-2008
Last Reviewed: 09-Jun-2008
To be reviewed: 09-Jun-2011
Metadata author:
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS)
Geophysicist
3354 College Road
Fairbanks, AK 99709-3707
USA

907-451-5021 (voice)
907-451-5050 (FAX)
dggspubs@alaska.gov

Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays.
Contact_Instructions:
Please contact us through the e-mail address above whenever possible.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.6 on Tue Sep 8 12:31:37 2009