Imaging spectroscopy, also known as hyperspectral remote sensing, is based on the characterization of Earth surface materials and processes through spectrally-resolved measurements of the light interacting with matter. The potential of imaging spectroscopy for Earth remote sensing has been demonstrated since the 1980s. However, most of the developments and applications in imaging spectroscopy have largely relied on airborne spectrometers, as the amount and quality of space-based imaging spectroscopy data remain relatively low to date. The upcoming Environmental Mapping and Analysis Program (EnMAP) German imaging spectroscopy mission is intended to fill this gap. An overview of the main characteristics and current status of the mission is provided in this contribution. The core payload of EnMAP consists of a dual-spectrometer instrument measuring in the optical spectral range between 420 and 2450 nm with a spectral sampling distance varying between 5 and 12 nm and a reference signal-to-noise ratio of 400:1 in the visible and near-infrared and 180:1 in the shortwave-infrared parts of the spectrum. EnMAP images will cover a 30 km-wide area in the across-track direction with a ground sampling distance of 30 m. An across-track tilted observation capability will enable a target revisit time of up to four days at the Equator and better at high latitudes. EnMAP will contribute to the development and exploitation of spaceborne imaging spectroscopy applications by making high-quality data freely available to scientific users worldwide.

The EnMAP Spaceborne Imaging Spectroscopy Mission for Earth Observation

The past decade or so has seen a dramatic change in the way that economists can learn by watching our planet from above A revolution has taken place in remote sensing and allied fields such as computer science, engineering, and geography Petabytes of satellite imagery have become publicly accessible at increasing resolution, many algorithms for extracting meaningful social science information from these images are now routine, and modern cloud-based processing power allows these algorithms to be run at global scale This paper seeks to introduce economists to the science of remotely sensed data, and to give a flavor of how this new source of data has been used by economists so far and what might be done in the future

https://pubs.aeaweb.org/doi/pdfplus/10.1257/jep.30.4.171

The View from Above: Applications of Satellite Data in Economics

The unmanned aerial vehicle (UAV) sensors and platforms nowadays are being used in almost every application (e.g., agriculture, forestry, and mining) that needs observed information from the top or oblique views. While they intend to be a general remote sensing (RS) tool, the relevant RS data processing and analysis methods are still largely ad-hoc to applications. Although the obvious advantages of UAV data are their high spatial resolution and flexibility in acquisition and sensor integration, there is in general a lack of systematic analysis on how these characteristics alter solutions for typical RS tasks such as land-cover classification, change detection, and thematic mapping. For instance, the ultra-high-resolution data (less than 10 cm of Ground Sampling Distance (GSD)) bring more unwanted classes of objects (e.g., pedestrian and cars) in land-cover classification; the often available 3D data generated from photogrammetric images call for more advanced techniques for geometric and spectral analysis. In this paper, we perform a critical review on RS tasks that involve UAV data and their derived products as their main sources including raw perspective images, digital surface models, and orthophotos. In particular, we focus on solutions that address the “new” aspects of the UAV data including (1) ultra-high resolution; (2) availability of coherent geometric and spectral data; and (3) capability of simultaneously using multi-sensor data for fusion. Based on these solutions, we provide a brief summary of existing examples of UAV-based RS in agricultural, environmental, urban, and hazards assessment applications, etc., and by discussing their practical potentials, we share our views in their future research directions and draw conclusive remarks.

Unmanned Aerial Vehicle for Remote Sensing Applications—A Review

A framework for mapping tree species combining Hyperspectral and LiDAR data: role of selected classifiers and sensor across three spatial scales

Landslides represent major natural hazards, which cause every year significant loss of lives and damages to buildings, properties and lifelines. In the last decades, a significant increase in landslide frequency took place, in concomitance to climate change and the expansion of urbanized areas. Remote sensing techniques represent a powerful tool for landslide investigation: applications are traditionally divided into three main classes, although this subdivision has some limitations and borders are sometimes fuzzy. The first class comprehends techniques for landslide recognition, i.e., the mapping of past or active slope failures. The second regards landslide monitoring, which entails both ground deformation measurement and the analysis of any other changes along time (e.g., land use, vegetation cover). The third class groups methods for landslide hazard analysis and forecasting. The aim of this paper is to give an overview on the applications of remote-sensing techniques for the three categories of landslide investigations, focusing on the achievements of the last decade, being that previous studies have already been exhaustively reviewed in the existing literature. At the end of the paper, a new classification of remote-sensing techniques that may be pertinently adopted for investigating specific typologies of soil and rock slope failures is proposed.

/pdf/remote-sensing-for-landslide-investigations-an-overview-of-27qvaxk6oy.pdf

Remote Sensing for Landslide Investigations: An Overview of Recent Achievements and Perspectives

Multi- and hyperspectral geologic remote sensing: A review

The application of day and night time ASTER satellite imagery for geothermal and mineral mapping in East Africa

In the production of calcined kaolin, the on-line monitoring of the calcination reaction is becoming more relevant for the generation of optimal products. In this context, this study aimed to asses...

/pdf/toward-an-on-line-characterization-of-kaolin-calcination-1mfsductx8.pdf

Toward an on-line characterization of kaolin calcination process using short-wave infrared spectroscopy

Recent improvements and availability of optical to infrared to thermal satellite and airborne sensors opens up the opportunity for advancing surface mineralogy and geological mapping. Such mapping may include the identification of alteration zones for exploration activities or monitoring ore quality and inventory within open cuts. Remote sensing technology is also on the cusp of major new developments with deployment of hyperspectral sensor satellites, UAV/drones and proximal mine face sensors. Such imagery will provide additional compositional information within the geoscientists tool kit for regional to mine site scale studies. In particular the improvement and access of higher spectral and sometimes, spatial resolution will assist the mapping of different AlOH, MgOH, carbonate, sulphate and iron oxide mineral identities, potentially related to phyllic, propylitic and argillic alteration zones. Integration of such remote sensing map products with regional geophysical data and other geoscience information has in the past and will in the future refine and improve its interpretation. Satellite imagery and large-scale airborne survey acquisitions can be particularly useful for greenfields exploration in exposed terrain within arid to semi-arid remote areas. UAV/drone platform remote sensing is increasingly being applied to brownfields open cut observations and mine site environmental monitoring. However, an understanding of the caveats and limitations on remote sensing is essential. In particular, knowledge of the issues of sensor resolution, and illumination, atmospheric and ground conditions at the time of acquisition is important. This paper aims to provide a brief overview of current available remote sensing technologies, a cross section of related case studies, and a roadmap strategy for undertaking geological remote sensing applications.

Status and Developments in Geological Remote Sensing

Airborne Imaging Spectroradiometer for Applications (AISA) Hawk data was used to identify and map hydrothermal alteration mineralogy in Mount Berecha area of Main Ethiopian Rift valley. The Airborne image mapping was coupled with laboratory analysis involving reflectance spectroscopic measurements with the use of ASD FieldSpec for mineral and rock samples. The study was based in the shortwave infrared wavelength (SWIR) region. Laboratory spectra acquired from field data analysis served as guide in selecting image endmembers which were used as input in Spectral Angle Mapper (SAM) classification for mineral mapping. SWIR spectroscopy was able to detect the main very fine grained mineral assemblages which occur in the study area, including kaolinite, halloysite, opal, montmorillonite, nontronite, calcite, K-alunite, palygorskite, MgChlorite, zoisite, illite and mixtures of these minerals. SAM classification algorithm gives the overall classification of the alteration minerals of Berecha area and was used to generate the surficial mineral map of the study area. Berecha alteration is related to low sulfidation system and the most widespread alteration effects are represented essentially in advanced argillic alteration assemblage consisting mainly of kaolinite + opal + smectite + alunite which is likely of steam heated origin.

/pdf/mapping-of-hydrothermal-alteration-in-mount-berecha-area-of-31n6sy1ley.pdf

C.A. Hecker

Papers

Multi- and hyperspectral geologic remote sensing: A review

The application of day and night time ASTER satellite imagery for geothermal and mineral mapping in East Africa

Toward an on-line characterization of kaolin calcination process using short-wave infrared spectroscopy

Status and Developments in Geological Remote Sensing

Mapping of hydrothermal alteration in Mount Berecha area of main Ethiopian Rift using hyperspectral data