Integration of a Graph Network for Landslide Detection in Space-borne
Earth Observation
Abstract
Landslides pose a significant threat to society and infrastructure and
their occurrence is projected to increase in many regions under the
effect of climate change. There is an urgent demand for reliable
monitoring of this natural hazard. The combination of spaceborne remote
sensing data with state-of-the-art machine learning algorithms offers
valuable tools for landslide detection in remote areas. However, a key
limitation for the detection lies in the scale factor, especially for
methods relying on pixel neighbourhoods. This study presents an
innovative methodology which combines a spatial graph with SAR and
multi-spectral change products. The graph integrates the flow direction
based on the topography into the neighbourhood determination. This
unique neighbourhood allows for the preservation of the unique shape and
signature of an individual landslide. This paper compares the proposed
graph neighbourhood to a common square window approach. Therefore, a RFC
is trained with neighbourhood statistics from both approaches and
applied to landslides of varying extent. A research area in New
Zealand’s West Coast region is selected due to the continuous evolution
of a single landslide over multiple events. The graph approach shows
promising results, particularly for small-scale events which are
successfully detected while being missed by the common window approach.
Using the graph neighbourhood, we can even detect the smallest visible
extent of the landslide at 2-3 pixels (30-45m) width. The main
limitation of the proposed approach lies in the quality of the input
data. Future work will focus on the improvement of the Sentinel-1 and
Sentinel-2 pre-processing.