Multi-criteria evaluation of the shadow index performance of Landsat 8 OLI images

Xu, Yang; Zuo, Xiaoqing; Da-ming, Zhu; Xie, Wenbin; Li, Yongfa; Guo, Shipeng

doi:10.1080/01431161.2022.2122893

Cited by 1 publication

(1 citation statement)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Currently, hillshade extraction methods employ either graphics methods or modeling approaches [5]- [7]. Graphic methods usually use remote sensing images to identify shadows through processes such as thresholding [8], edge detection [7], and region growth [9]. Various indices, including the Combinational Shadow Index (CSI) [10], Shadow Detector Index (SDI) [11], and Shadow Enhancement Index (SEI) [10], have been established within this context.…”

Section: Introductionmentioning

confidence: 99%

To Ignore or Not: Understanding the Influence of Hillshade

Xian,

Wang,

et al. 2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

View full text Add to dashboard Cite

Hillshade poses an important challenge in remote sensing research at mountainous regions. In order to understand the influence of hillshade on the solar direct radiation (SDR) transfer process, this study performed the calculation of hillshade (including both self-shadow and cast-shadow) and the evaluation of its radiative effects over the Tibetan Plateau. When utilizing the ray tracing method to calculate hillshade, a search radius of 6 km (equivalent to 200 NASADEM pixels) efficiently captures about 99% of the hillshade area at a solar zenith angle (SZA) of 80°. And the necessary search radius decreases rapidly as the SZA decreases. By calculating the hillshade on the Tibetan Plateau, it was found that the surface experiences hillshade for approximately 10% of daylight hours, with more than 30% in the most severely impacted areas. The hillshade dynamics over the Tibetan Plateau reveal minimal seasonal variation but significant diurnal differences, moreover, the impact of hillshade varies throughout the day. It is worth noting that one hour after sunrise and one hour before sunset, the impact of hillshade reaches its maximum, with over 30% of the area covered by hillshade. In particular, ignoring the castshadow can lead to overestimating the average SDR of the entire plateau by 40 W/m² . This impact is most severe during the winter solstice. In contrast, with a smaller SZA, the influence of hillshade on SDR is minimal at noon.

show abstract