A Review of Landcover Classification with Very-High Resolution Remotely Sensed Optical Images-Analysis Unit,Model Scalability and Transferability

TL;DR

This paper systematically reviews landcover classification methods using very-high-resolution remote sensing images, focusing on deep learning techniques, analysis units, and challenges in scalability and transferability across different regions and data sources.

Contribution

It provides a comprehensive overview of landcover mapping methods, emphasizing issues of data imbalance, domain gaps, and multi-source fusion, which are less addressed in prior reviews.

Findings

Analyzes various analysis units and learning methods for landcover classification.

Discusses challenges and solutions for data sparsity, domain gaps, and multi-source fusion.

Offers future directions for scalable and transferable remote sensing classification.

Abstract

As an important application in remote sensing, landcover classification remains one of the most challenging tasks in very-high-resolution (VHR) image analysis. As the rapidly increasing number of Deep Learning (DL) based landcover methods and training strategies are claimed to be the state-of-the-art, the already fragmented technical landscape of landcover mapping methods has been further complicated. Although there exists a plethora of literature review work attempting to guide researchers in making an informed choice of landcover mapping methods, the articles either focus on the review of applications in a specific area or revolve around general deep learning models, which lack a systematic view of the ever advancing landcover mapping methods. In addition, issues related to training samples and model transferability have become more critical than ever in an era dominated by data-driven approaches, but these issues were addressed to a lesser extent in previous review articles regarding remote sensing classification. Therefore, in this paper, we present a systematic overview of existing methods by starting from learning methods and varying basic analysis units for landcover mapping tasks, to challenges and solutions on three aspects of scalability and transferability with a remote sensing classification focus including (1) sparsity and imbalance of data; (2) domain gaps across different geographical regions; and (3) multi-source and multi-view fusion. We discuss in detail each of these categorical methods and draw concluding remarks in these developments and recommend potential directions for the continued endeavor.