Day: June 7, 2012

Forest Delineation Based on Airborne LIDAR Data

/ Matt Artz

Remote Sensing, 2012, 4(3), 762-783

Lothar Eysn, Markus Hollaus, Klemens Schadauer and Norbert Pfeifer

“The delineation of forested areas is a critical task, because the resulting maps are a fundamental input for a broad field of applications and users. Different national and international forest definitions are available for manual or automatic delineation, but unfortunately most definitions lack precise geometrical descriptions for the different criteria. A mandatory criterion in forest definitions is the criterion of crown coverage (CC), which defines the proportion of the forest floor covered by the vertical projection of the tree crowns. For loosely stocked areas, this criterion is especially critical, because the size and shape of the reference area for calculating CC is not clearly defined in most definitions. Thus current forest delineations differ and tend to be non-comparable because of different settings for checking the criterion of CC in the delineation process. This paper evaluates a new approach for the automatic delineation of forested areas, based on airborne laser scanning (ALS) data with a clearly defined method for calculating CC.

“The new approach, the ‘tree triples’ method, is based on defining CC as a relation between the sum of the crown areas of three neighboring trees and the area of their convex hull. The approach is applied and analyzed for two study areas in Tyrol, Austria. The selected areas show a loosely stocked forest at the upper timberline and a fragmented forest on the hillside. The fully automatic method presented for delineating forested areas from ALS data shows promising results with an overall accuracy of 96%, and provides a beneficial tool for operational applications.”

Thinking About Place, Spatial Behavior, and Spatial Processes in Childhood Obesity

/ Matt Artz

American Journal of Preventive MedicineAmerican Journal of Preventive Medicine, May 2012, Vol. 42, No. 5

“There is no single solution to the childhood obesity epidemic, but there is a need for transdisciplinary collaboration and approaches that consider the potential mechanisms that promote or reduce obesity at all levels of enquiry, from cells to society. In this theme issue of the American Journal of Preventive Medicine,we focus on place (obesogenic and leptogenic environments), specifıcally the use of GIS, related technologies, and spatial analytical methods in the study of childhood obesity.

“A proven technology, GIS facilitates the measurement, management, mapping, and analysis of the real world. GIS is not a panacea, but the integrative nature of GIS and its linkage with spatial statistical analysis offer an important means of better understanding and dealing with some of the most pressing problems of our time and provide valuable tools for researchers and policymakers alike. Not surprisingly, as GIS has matured (the ready availability of geospatial data, enhanced visualization tools, and advanced spatial analysis methods), there has been an explosion of interest in the application and use of spatial concepts and methods in health-related research.”