Airborne Hyperspectral Data Acquisition and Processing in the Arctic: A Pilot Study Using the Hyspex Imaging Spectrometer for Wetland Mapping

A pilot study for mapping the Arctic wetlands was conducted in the Yukon Flats National Wildlife Refuge (Refuge), Alaska. It included commissioning the HySpex VNIR-1800 and the HySpex SWIR-384 imaging spectrometers in a single-engine Found Bush Hawk aircraft, planning the flight times, direction, and speed to minimize the strong bidirectional reflectance distribution function (BRDF) effects present at high latitudes and establishing improved data processing workflows for the high-latitude environments. Hyperspectral images were acquired on two clear-sky days in early September, 2018, over three pilot study areas that together represented a wide variety of vegetation and wetland environments. Steps to further minimize BRDF effects and achieve a higher geometric accuracy were added to adapt and improve the Hyspex data processing workflow, developed by the German Aerospace Center (DLR), for high-latitude environments. One-meter spatial resolution hyperspectral images, that included a subset of only 120 selected spectral bands, were used for wetland mapping. A six-category legend was established based on previous U.S. Geological Survey (USGS) and U.S. Fish and Wildlife Service (USFWS) information and maps, and three different classification methods—hybrid classification, spectral angle mapper, and maximum likelihood—were used at two selected sites. The best classification performance occurred when using the maximum likelihood classifier with an averaged Kappa index of 0.95; followed by the spectral angle mapper (SAM) classifier with a Kappa index of 0.62; and, lastly, by the hybrid classifier showing lower performance with a Kappa index of 0.51. Recommendations for improvements of future work include the concurrent acquisition of LiDAR or RGB photo-derived digital surface models as well as detailed spectra collection for Alaska wetland cover to improve classification efforts.info:eu-repo/semantics/publishedVersio

Airborne Hyperspectral Data Acquisition and Processing in the Arctic: A Pilot Study Using the Hyspex Imaging Spectrometer for Wetland Mapping

A pilot study for mapping the Arctic wetlands was conducted in the Yukon Flats National Wildlife Refuge (Refuge), Alaska. It included commissioning the HySpex VNIR-1800 and the HySpex SWIR-384 imaging spectrometers in a single-engine Found Bush Hawk aircraft, planning the flight times, direction, and speed to minimize the strong bidirectional reflectance distribution function (BRDF) effects present at high latitudes and establishing improved data processing workflows for the high-latitude environments. Hyperspectral images were acquired on two clear-sky days in early September, 2018, over three pilot study areas that together represented a wide variety of vegetation and wetland environments. Steps to further minimize BRDF effects and achieve a higher geometric accuracy were added to adapt and improve the Hyspex data processing workflow, developed by the German Aerospace Center (DLR), for high-latitude environments. One-meter spatial resolution hyperspectral images, that included a subset of only 120 selected spectral bands, were used for wetland mapping. A six-category legend was established based on previous U.S. Geological Survey (USGS) and U.S. Fish and Wildlife Service (USFWS) information and maps, and three different classification methods—hybrid classification, spectral angle mapper, and maximum likelihood—were used at two selected sites. The best classification performance occurred when using the maximum likelihood classifier with an averaged Kappa index of 0.95; followed by the spectral angle mapper (SAM) classifier with a Kappa index of 0.62; and, lastly, by the hybrid classifier showing lower performance with a Kappa index of 0.51. Recommendations for improvements of future work include the concurrent acquisition of LiDAR or RGB photo-derived digital surface models as well as detailed spectra collection for Alaska wetland cover to improve classification efforts

ASFHyP3/hyp3-gamma: HyP3 GAMMA v4.6.0

Added water_map entrypoint to create a water map product Option to output decibel scaled RTC products --scale parameter to rtc entrypoint now accepts decibel scale parameter to rtc_sentinel.rtc_sentinel_gamma now accepts decibel Changed Upgraded to hyp3-metadata v1.2.3 from v1.1.

ASFHyP3/hyp3-gamma: HyP3 GAMMA v6.3.1

Fixed Phase unwrapping for very large interferograms is now performed in two range patches to keep total memory requirement under 31,600 MB. Fixes #316

ASFHyP3/hyp3-gamma: HyP3 GAMMA v6.3.0

Changed Upgraded to GAMMA software version 20230712 from 2022063

ASFHyP3/hyp3-lib: HyP3-lib v2.0.1

<h3>Fixed</h3> <ul> <li><code>distribute</code> action to use updated version similar to <code>hyp3-sdk</code></li> </ul&gt

ASFHyP3/hyp3-lib: HyP3-lib v2.0.2

<h3>Fixed</h3> <ul> <li>Install <code>build</code> dependency to fix <code>distribute</code> action.</li> </ul&gt

ASFHyP3/hyp3-gamma: HyP3 GAMMA v8.0.1

<h3>Changed</h3> <ul> <li>Upgraded to <code>hyp3lib>=3,<4</code> from <code>>=2,<3</code></li> <li>All requirements for the conda environment are once again installed via conda in <code>environment.yml</code>, eliminating the workaround for <a href="https://github.com/ASFHyP3/hyp3-gamma/issues/421">#421</a> implemented in v5.7.2.</li> </ul&gt

ASFHyP3/hyp3-gamma: HyP3 GAMMA v6.4.0

<h3>Added</h3> <ul> <li>The <code>--phase-filter-parameter</code> option now accepts a value of <code>0.0</code>, which indicates that the adaptive phase filter will be skipped.</li> <li>Documentation for the adaptive phase filter parameter in product readme and xml files.</li> </ul&gt

ASFHyP3/hyp3-gamma: HyP3 GAMMA v7.0.0

<h3>Changed</h3> <ul> <li>Upgraded <code>hyp3lib</code> dependency to version <code>2.x.x</code>.</li> <li>As of <a href="https://github.com/ASFHyP3/hyp3-lib/releases/tag/v2.0.0">HyP3-lib v2.0.0</a>, the <a href="https://dataspace.copernicus.eu/">Copernicus Data Space Ecosystem (CDSE)</a> will now be used for downloading Sentinel-1 orbit files from ESA.</li> <li>CDSE credentials must be provided via the <code>--esa-username</code> and <code>--esa-password</code> command-line options or the <code>ESA_USERNAME</code> and <code>ESA_PASSWORD</code> environment variables.</li> </ul&gt