Raymond F. Kokaly
Todd M. Hoefen
Trude V.V. King
Michaela R. Johnson
20170922
Airborne imaging spectrometer data collected for characterizing mineral resources near Nabesna, Alaska, 2014: CAL03
remote-sensing image
Denver, CO
U.S. Geological Survey
http://dx.doi.org/10.5066/F7DN435W
Imaging spectrometer (hyperspectral) data were collected using the HyMap™ sensor over the Nabesna Area of Interest (AOI) in the eastern Alaska Range, July 14 and July 21, 2014. The primary study area was a remote part of the eastern Alaska Range where porphyry deposits are exposed. The HyMap imaging spectrometer measured reflected sunlight in 126 narrow channels spanning the 0.4 to 2.5 micron wavelength region of the electromagnetic spectrum. The data were collected at a nominal 6-m ground-instantaneous field of view (GIFOV). A total 1,900 square kilometers were collected. This data release provides flight line data for the survey and a report describing the dataset and procedures
The hyperspectral survey was flown as one component of a U.S. Geological Survey (USGS) mineral resource project with the goals of enhancing geologic mapping and developing methods to identify and characterize mineral deposits elsewhere in Alaska. Hyperspectral surveying is one method that can be used to rapidly acquire data about the distributions of surficial materials, including different types of bedrock and ground cover.
This is part of a raw data release consisting of 7 flightlines and 2 calibration lines. Each flightline has radiance and geocorrection data files associated.
HyVista_Data_Products_USGS_2014B.pdf - Contractor report from HyVista Corporation Pty Ltd. This report describes the files in the HyMap data package and procedures used to produce the dark current corrected digital number (DN) data, radiance calibrated data (at sensor), and geometric correction files data.
Raw Files from Recording Media
"filename".bil - HyMap dark current corrected image data, 128 bands x 512 pixels x N lines. This file is the 128 band, 512 pixel wide image in BIL format and in dark/electronic offsets corrected DN (digital numbers).
"filename".hdr – associated ENVI header file.
"filename".log - ASCII file containing various flight parameters.
Radiance Data Files
"filename"_rad.bil – HyMap image data, 126 channels x 512 pixels x N lines (BIL format).
"filename"_rad.hdr – associated ENVI header file.
"filename"_q.bil – single band (VIS ch25) quicklook image (BSQ format). *image will be flipped
"filename"_q.hdr – associated ENVI header file.
"filename"_c.cal – internal lamp data, 128 channels x 10 pixels.
"filename"_c.hdr – associated ENVI header file.
"filename"_d.drk – dark current data, 128 channels x 10 pixels.
"filename"_d.hdr – associated ENVI header file.
"filename".JPG – composite true colour (3 band RGB) image in JPG format.
"filename"_dycal.txt - dark current corrected DN measurement of internal lamp.
"filename"_facet.txt - ratio of scan mirror reflectance derived from in-flight data.
Geocorrection Data Files
"filename"_geo.img – 3 band colour (RGB) geocoded "quicklook" image.
"filename"_geo.hdr – associated ENVI header file.
"filename"_geo.jpg – 3 band colour (RGB) geocoded "quicklook" image.
"filename"_geo.hdr – associated ENVI header file.
"filename"_geo.ers – associated ER-MAPPER header file.
"filename"_glt.bsq – Geographic Lookup Table file.
"filename"_glt.hdr – associated ENVI header file.
"filename"_igm.bil – Input Geometry file.
"filename"_igm.hdr – associated ENVI header file.
"filename"_ephemeris.txt – Aircraft ephemeris data for each scan line.
"filename"_report.txt – summary of the geocorrection parameters.
"filename".ini - ASCII file that lists some of the inputs to the geo-correction software.
20140714
20140721
ground condition
Not planned
-143.37637891
-141.921433884
62.349099479
62.005457724
USGS Thesaurus
hyperspectral imaging
remote sensing
infrared imaging
visible light imaging
none
spectroscopy
HyMap
imaging spectroscopy
shortwave infrared
SWIR
visible-near infrared
VNIR
Environment for Visualizing Images
ENVI
Mineral Resources Program
MRP
USGS Metadata Identifier
USGS:5953463de4b062508e3c7a29
Geographic Names Information System
Alaska
Canada
Yukon Territory
Alaska Range
Wrangell Mountains
Nutzotin Mountains
Wrangell-Saint Elias National Park
Wrangell-Saint Elias National Preserve
Bond Creek
Nabesna River
Chisana River
Nabesna
Nabesna Glacier
Orange Hill
none
There is no guarantee concerning the accuracy of the data. Any user who modifies the data is obligated to describe the types of modifications they perform. Data have been checked to ensure the accuracy. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to http://www.usgs.gov/privacy.html for the USGS disclaimer.
Todd M. Hoefen
U.S. Geological Survey
mailing and physical
W 6th Ave and Kipling St, Box 25046, MS 964D, Bldg 20
Denver
Colorado
80225
USA
303.236.2456
thoefen@usgs.gov
This release of the dataset was funded by the Mineral Resources Program (MRP)and collected with the HyVista Corporation (HyMap™ hyperspectral scanner manufactured by Integrated Spectronics Pty Ltd).
No formal attribute accuracy tests were conducted
No formal logical accuracy tests were conducted
Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
No formal positional accuracy tests were conducted
No formal positional accuracy tests were conducted
The (hyperspectral) data were collected using the HyMap™ sensor over the Nabesna Area of Interest (AOI) in the eastern Alaska Range, July 14 and July 21, 2014. The far eastern end of the data crossed the U.S. border into the Yukon Territory of Canada with a maximum of approximately 3 km (1.9 mi). The HyMap data products that HyVista Corporation delivered were dark current corrected DN data, radiance calibrated data (at sensor) and geometric correction files. All image data are delivered as ENVI compatible files.
In operation, the HyMap sensor records 128 spectral bands of data. However, the delivered radiance data contains 126 bands because bands in the overlap region of the VIS and NIR modules are deleted during the pre-processing steps.
Spectral and radiometric calibration of the HyMap sensor was accomplished prior to the survey and this information was used to allow the conversion of the raw DN counts to radiance values in µW/cm2 nm sr.
The HyMap sensor has 4 spectrometers (VIS, NIR, SWIR1 and SWIR2), each producing 32 recorded spectral bands of imagery. The VIS and NIR provide contiguous sampling across the 900 nm region. In fact, the spectrometers are set up to provide a slight overlap in the long wavelength region of the VIS spectrometer and the short wavelength region of the NIR spectrometer.
During processing to generate radiance spectra, 2 bands at the overlap region of the VIS and NIR spectrometers are deleted.
HyVista Corporation uses proprietary software for geo-correcting hyperspectral images collected by the HyMap airborne hyperspectral scanner. The software uses HyMap sensor position and orientation data collected at the same time as the image to calculate the position of each pixel in the image. The software uses this position information to map input image pixel values onto a geo-referenced grid of output image pixels.
The geo-correction software also makes use of a Digital Elevation Model (or DEM) of the geographic region containing the imagery.
The geo-correction software produces an "_igm" input geometry file, a "_glt" geometry lookup table file and, finally, the geo-corrected output image. All geo-coded products are in the UTM projection and WGS84 datum.
20140721
Geographic Names Index System (GNIS) placenames: Wrangell-Saint Elias National Park and Preserve
Raster
Universal Transverse Mercator
7
0.9996
-141.0
0.0
500000.0
0.0
row and column
5.6
5.6
Meter
D_WGS_1984
WGS_1984
6378137.0
298.257223563
HyVista_Data_Products_USGS_2014B.pdf
Contractor report from HyVista Corporation Pty Ltd. This report describes the files in the HyMap data package and procedures used to produce the dark current corrected digital number (DN) data, radiance calibrated data (at sensor), and geometric correction files data. The report is provided with this data release at, https://www.sciencebase.gov/catalog/file/get/59528eece4b062508e3c76d5?name=HyVista_Data_Products_USGS_2014B.pdf/.
HyMap raw files from recording media: "filename".bil - HyMap dark current corrected image data, 128 bands x 512 pixels x N lines.
This file is the 128 band, 512 pixel wide image in BIL format and in dark/electronic offsets corrected DN (digital numbers). The HyMap imagery is digitised to 12 bits.
HyMap raw files from recording media: "filename".hdr - associated ENVI header file
ENVI formatted header file for the above BIL file and contains information on the image size, data format, band names, spectral band wavelengths and bandwidths.
HyMap raw files from recording media: "filename".log - ASCII file containing various flight parameters.
The log file is an ASCII file generated when data is downloaded from the flight recording media. The file contains various information such as GPS and IMU measurements, sensor parameters such as power supply voltages and temperatures, master clock through which all other measurements are synchronised and the timing associated with scan line acquisition. The log file is used in subsequent processing steps such as geo-correction. The log file can only be fully decoded by the use of proprietary software and as delivered it is of no real value to the user.
HyMap radiance data files: "filename"_rad.bil – HyMap image data, 126 bands x 512 pixels x N lines (BIL format).
This file is the 126 band, 512 pixel wide image in BIL format that has been converted to physical units of radiance (strictly, the measurement is "at sensor radiance"). The data are in µW/cm2 nm sr. The in-flight recorded DN have been corrected for dark current/electronic offsets and converted to radiance using laboratory radiometric calibration information and in-flight measurements of the on-board calibration lamp. Typically the file will be labeled as "filename"_rad.bil or "filename"_radiance.bil to further indicate that the data is in radiance units. The preferred data format is a two byte, integer format and the data is rescaled to preserve dynamic range, especially in the SWIR range. This rescaling involves multiplying bands 1 – 62 by 1000 and bands 63 – 126 by 4000.
HyMap radiance data files: "filename"_rad.hdr – associated ENVI header file.
Associated header file for filename_rad.bil. The wavelength and bandwidth (in nanometers) information from the radiance BIL file is imbedded in the ENVI header file (*.hdr).
HyMap radiance data files: "filename"_q.img – single band (VIS ch25) quicklook image (BSQ format). *image will be flipped
This file is a single band image in BSQ format. The file is used to provide a "quicklook" at the HyMap image. The image has the same dimensions as the radiance file but will be displayed in a mirrored orientation as it has been derived from the "raw" HyMap data. Therefore the image is displayed "as it is recorded on the HyMap system". The band used is from VIS band 25.
HyMap radiance data files: "filename"_q.hdr – associated ENVI header file.
Associated header file for filename_q.bil
HyMap radiance data files: "filename"_c.cal – internal lamp data, 128 bands x 10 pixels.
During image acquisition, the HyMap sensor measures the on-board calibration lamp, acquiring a 10 pixel wide "image" after alternate image scan lines. This data is in DN and is not dark corrected. This file is used by HyVista Corp. during the radiometric processing. The data in this file are not dark current/offset corrected. Typically, this file will be delivered in the HyMap 128 channel mode. To most users, this file is of little value and has some properties that require additional information from HyVista Corp for a complete understanding.
HyMap radiance data files: "filename"_c.hdr – associated ENVI header file.
Associated header file for filename_c.cal
HyMap radiance data files: "filename"_d.drk – dark current data, 128 bands x 10 pixels.
During image acquisition, the HyMap sensor measures detector dark currents and offsets, acquiring a 10 pixel wide "image" after alternate image scan lines. The data is in DN and can be used to examine the dark current statistics. Typically, this file will be delivered in the HyMap 128 channel mode.
HyMap radiance data files: "filename"_d.hdr – associated ENVI header file.
Associated header file for filename_d.drk
HyMap radiance data files: "filename".JPG – composite true colour (3 band RGB) image in JPG format.
This file is a 3-band colour image of the imported data. It is displayed as RGB as R-VISband18, G-VISband10, B-VISband4. It is radiance corrected and Gaussian stretched to provide the best quality picture and is provided in the common JPG image format.
HyMap radiance data files: "filename"_dycal.txt - dark current corrected DN measurement of internal lamp
The HyMap sensor contains an internal, stabilised lamp which is continuously monitored during airborne image acquisition. Measurements of the internal lamp are used o monitor small changes in the radiometric response that are due to changes in temperature and humidity. "DyCal" represents a dynamic calibration; recorded when the scan mirrors are rotating. The "filename_dycal.txt " is used in the processing that converts raw DN to radiance data.
HyMap radiance data files: "filename"_facet.txt - ratio of scan mirror reflectance derived from in-flight data
The Hymap sensor has a two faceted scan mirror and during manufacture there is a limit to how well the reflectance of one mirror can be matched to the reflectance of the other. A variation of reflectance from one mirror to the other would cause 2- line striping in the imagery. The "filename_facet.txt" is a two column ASCII text file that has the band number (1-128) in column one and the ratio of mirror facet 1 to the reflectance of mirror facet 2. This file is used in the radiance processing to remove 2-line striping in the radiance imagery.
HyMap geocorrection data files: "filename"_geo.img – 3 band colour (RGB) geocoded "quicklook" image.
Typically a 3 band colour (RGB) geo-coded "quicklook" image. Bands used to derive the "true colour" image are R-ch15, G-ch9, B-ch3. When geo-coded flight lines are mosaiced together, make sure to set the background value to ignore to -99. The null pixels around the images have this value. The "quicklook" image is produced with an associated ENVI header file and also produced with an associated ER-MAPPER header file. ("filename"_geo.ers)
HyMap geocorrection data files: "filename"_geo.hdr – associated ENVI header file.
Associated header file for filename_geo.img
HyMap geocorrection data files: "filename"_geo.ers – associated ER-MAPPER header file.
ER-MAPPER header file produced with the quicklook image, "filename"_geo.img.
HyMap geocorrection data files: "filename"_glt.bsq – Geographic Lookup Table file.
The geometric lookup table file represents much of the important information that is created in the geo-correction process. The "_glt" file contains the information about which original pixel occupies which output pixel in the final product. Additionally, it is sign-coded to indicate if a certain output pixel is "real" or a nearest-neighbor in-fill pixel. The "_glt" file is a geo-corrected product, with a fixed pixel size projected into a rotated UTM system. The pixel size, scene elevation, UTM zone number, and rotation angle information is reported in an associated ASCII header file. The "_glt" file is two-byte integer binary data in a BIL format. The two bands of the "_glt" file refer to original sample number and original line number, respectively. The sign of the value indicates whether the pixel is an actual image pixel, located at its proper position indicated by a positive value) or a nearest-neighbor in-fill pixel placed to fill an under-sampled image gap (indicated by a negative value). A zero value signifies that no input pixel corresponds to this output pixel. The importance of the "_glt" image and its role in identifying image gaps and in-fill pixels must be stressed, especially for studies involving small targets. The geometric lookup table file can be used to geo-correct any band or derived product through a simple lookup table procedure.
HyMap geocorrection data files: "filename"_glt.hdr – associated ENVI header file.
Associated header file for filename_glt.bsq
HyMap geocorrection data files: "filename"_igm.bil – Input Geometry file.
Input geometry file that denotes the UTM Easting and Northing values derived by the geo-correction process for each original image pixel. The first band contains UTM Easting values in meters and the second band contains UTM Northing values in meters for each original pixel. The input geometry file has the same spatial size as the raw HyMap imagery. The file is double precision, binary data in a BIL format. The pixel size, and UTM zone number information are given in an associated ASCII header file. The input geometry file itself is not geo-corrected, but does contain the geo-location information for each original raw pixel.
HyMap geocorrection data files: "filename"_igm.hdr – associated ENVI header file.
Associated header file for filename_igm.hdr
HyMap geocorrection data files: "filename"_ephemeris.txt – Aircraft ephemeris data for each scan line.
Aircraft ephemeris information for each scan line. The file contains: line number, UTM X meters), UTM Y (meters), altitude (meters), pitch (degrees), roll (degrees), and heading (degrees).
HyMap geocorrection data files: "filename"_report.txt – summary of the geo-correction parameters.
This file contains a summary of data used and generated by the geo-correction process.
HyMap geocorrection data files: "filename".ini - ASCII file that lists some of the inputs to the geo-correction software
This ASCII file contains some of the parameters entered into the geo-correction processing.
U.S. Geological Survey – ScienceBase
U.S. Geological Survey – ScienceBase
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
Colorado
80225
USA
1-888-275-8747
sciencebase@usgs.gov
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
20200929
Michaela R. Johnson
U.S. Geological Survey
Physical Scientist
mailing and physical
W 6th Ave, Kipling St, Box 26046, MS 964, Bldg 20
Denver
Colorado
80225
USA
303.236.2464
mrjohns@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998