THE SOURCE – DATA
THE PROCESS OF HOW WE COLLECT OUR DATA
The area of interest is typically defined by the principal investigator and relates to a science question. A pixel size may be chosen to reflect the spatial process length scale.
Flight line definition is a process to optimise the acquisition process, achieving the required image resolution and covering the area of interest with minimised BRDF effects where possible.
Imaging (also known as photo missions) flights require a special permission and must be applied for well in advance of any flight mission.
Flight plans, as shown below, consist of imaging missions strung together by transfer segments to optimise a sortie of the research aircraft and enable coordination with the in situ teams.
Flights are carried out once weather conditions are optimal and other constraints, like time of year, are met. The flight lines defined earlier are used in the flight management system to ensure the data are collected where planned.
The acquired raw data stream is downloaded after the flight mission and ingested by the processing and archiving facility (PAF). The typical levels are raw data (L0), calibrated data (L1) and reflectance data (L2).
Metadata helps to describe and identify the primary data, achieving long-term use.
Products are calculated from either L1 or L2 data and often constitute parameters that are found through model inversions, such as estimates of canopy parameters like chlorophyll or water content.
EXAMPLES OF DIFFERENT APPLICATIONS
RGB combination of vegetation parameters
Estimation of sun induced fluorescence
NOx mapping over greater Zurich area by EMPA
Mosaic of APEX data over greater Zurich area for a variety of applications
Snow grain size map of the Findelen glacier (Switzerland)
Alpine area in the Swiss Alps used for ungulate movement pattern study
DATA ACCESS POLICY
The ARES will adopt a rigorous data-sharing attitude. This will be implemented following the guidelines of the GEOSS Data Sharing Principles, namely full and open exchange of data, metadata and products, recognizing relevant Swiss National Science Foundation (SNSF) policies and FAIR principles; all shared data, metadata and products will be made available; and all shared data, metadata and products being free of charge or no more than cost of reproduction will be applicable for research and education for the proposing team. In addition, the team will set forth a number of rules, defining protected principal investigator times for each internal applicant. For all other (external) users, a common data policy, including property rights as well as a cost model will be developed. In turn, data recipients are asked to provide a data management plan, sending feedback to the facility, allowing steady improvement of its services and output.
DATA SET: Plastic Abundance in Water Bodies
The subsets linked below are imaging spectroscopy data (georectified radiance) of artificially distributed PET bottles in two different lakes in Switzerland (Hallwilersee and Greifensee).
The data sets were acquired with APEX and AVIRIS-NG in 2018.
Ground reference measurements carried out in association with the airborne data sets can be found here.
As the reference to be used for these data sets please cite the IGARSS paper:
A. Hueni and S. Bertschi, “DETECTION OF SUB-PIXEL PLASTIC ABUNDANCE ON WATER SURFACES USING AIRBORNE IMAGING SPECTROSCOPY,” in IGARSS 2020 – 2020 IEEE International Geoscience and Remote Sensing Symposium, 26 Sept.-2 Oct. 2020 2020, pp. 6325-6328, doi: 10.1109/IGARSS39084.2020.9323556.
For further information please refer to the MSc Thesis of Sonja Bertschi.
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