Wildland-urban interface in California using remote sensing data

Due to the mixed distribution of buildings and vegetation, wildland-urban
interface (WUI) areas are characterized by complex fuel distributions and
geographical environments. The behavior of wildfires occurring in the WUI
often leads to severe hazards and significant damage to man-made
structures. Therefore, WUI areas warrant more attention during the
wildfire season. Due to the ever-changing dynamic nature of California’s
population and housing, the update frequency and resolution of WUI maps
that are currently used can no longer meet the needs and challenges of
wildfire management and resource allocation for suppression and mitigation
efforts. Recent developments in remote sensing technology and data
analysis algorithms pose new opportunities for improving WUI mapping
methods. WUI areas in California were directly mapped using building
footprints extracted from remote sensing data by Microsoft along with the
fuel vegetation cover from the LANDFIRE dataset in this study. To
accommodate the new type of datasets, we developed a threshold criteria
for mapping WUI based on statistical analysis, as opposed to using more
ad-hoc criteria as used in previous mapping approaches. This method
removes the reliance on census data in WUI mapping, and does not require
the calculation of housing density. Moreover, this approach designates the
adjacent areas of each building with large and dense parcels of vegetation
as WUI, which can not only refine the scope and resolution of the WUI
areas to individual buildings, but also avoids zoning issues and
uncertainties in housing density calculation. Besides, the new method has
the capability of updating the WUI map in real-time according to the
operational needs. Therefore, this method is suitable for local
governments to map local WUI areas, as well as formulating detailed
wildfire emergency plans, evacuation routes, and management measures.