Day: April 30, 2010

Mapping Understory Vegetation using Phenological Characteristics Derived from Remotely Sensed Data

/ Matt Artz

Remote Sensing of Environment, In Press, Available online 17 April 2010

Mao-Ning Tuanmu, Andrés Viña, Scott Bearer, Weihua Xu, Zhiyun Ouyang, Hemin Zhang, and Jianguo Liu

“Understory vegetation is an important component in forest ecosystems not only because of its contributions to forest structure, function and species composition, but also due to its essential role in supporting wildlife species and ecosystem services. Therefore, understanding the spatio-temporal dynamics of understory vegetation is essential for management and conservation. Nevertheless, detailed information on the distribution of understory vegetation across large spatial extents is usually unavailable, due to the interference of overstory canopy on the remote detection of understory vegetation. While many efforts have been made to overcome this challenge, mapping understory vegetation across large spatial extents is still limited due to a lack of generality of the developed methods and limited availability of required remotely sensed data. In this study, we used understory bamboo in Wolong Nature Reserve, China as a case study to develop and test an effective and practical remote sensing approach for mapping understory vegetation. Using phenology metrics generated from a time series of Moderate Resolution Imaging Spectroradiometer data, we characterized the phenological features of forests with understory bamboo. Using maximum entropy modeling together with these phenology metrics, we successfully mapped the spatial distribution of understory bamboo (kappa: 0.59; AUC: 0.85). In addition, by incorporating elevation information we further mapped the distribution of two individual bamboo species, Bashania faberi and Fargesia robusta (kappa: 0.68 and 0.70; AUC: 0.91 and 0.92, respectively). Due to its generality, flexibility and extensibility, this approach constitutes an improvement to the remote detection of understory vegetation, making it suitable for mapping different understory species in different geographic settings. Both biodiversity conservation and wildlife habitat management may benefit from the detailed information on understory vegetation across large areas through the applications of this approach.”

Assessment of Planetary Geologic Mapping Techniques for Mars using Terrestrial Analogs: The SP Mountain Area of the San Francisco Volcanic Field, Arizona

/ Matt Artz

Planetary and Space Science, Volume 57, Issues 5-6, May 2009, Pages 510-532

Kenneth L. Tanaka, James A. Skinner Jr., Larry S. Crumpler, James M. Dohm

“We photogeologically mapped the SP Mountain region of the San Francisco Volcanic Field in northern Arizona, USA to evaluate and improve the fidelity of approaches used in geologic mapping of Mars. This test site, which was previously mapped in the field, is chiefly composed of Late Cenozoic cinder cones, lava flows, and alluvium perched on Permian limestone of the Kaibab Formation. Faulting and folding has deformed the older rocks and some of the volcanic materials, and fluvial erosion has carved drainage systems and deposited alluvium. These geologic materials and their formational and modificational histories are similar to those for regions of the Martian surface. We independently prepared four geologic maps using topographic and image data at resolutions that mimic those that are commonly used to map the geology of Mars (where consideration was included for the fact that Martian features such as lava flows are commonly much larger than their terrestrial counterparts). We primarily based our map units and stratigraphic relations on geomorphology, color contrasts, and cross-cutting relationships. Afterward, we compared our results with previously published field-based mapping results, including detailed analyses of the stratigraphy and of the spatial overlap and proximity of the field-based vs. remote-based (photogeologic) map units, contacts, and structures. Results of these analyses provide insights into how to optimize the photogeologic mapping of Mars (and, by extension, other remotely observed planetary surfaces). We recommend the following: (1) photogeologic mapping as an excellent approach to recovering the general geology of a region, along with examination of local, high-resolution datasets to gain insights into the complexity of the geology at outcrop scales; (2) delineating volcanic vents and lava-flow sequences conservatively and understanding that flow abutment and flow overlap are difficult to distinguish in remote data sets; (3) taking care to understand that surficial materials (such as alluvium and volcanic ash deposits) are likely to be under-mapped yet are important because they obscure underlying units and contacts; (4) where possible, mapping multiple contact and structure types based on their varying certainty and exposure that reflect the perceived accuracy of the linework; (5) reviewing the regional context and searching for evidence of geologic activity that may have affected the map area yet for which evidence within the map area may be absent; and (6) for multi-authored maps, collectively analyzing the mapping relations, approaches, and methods throughout the duration of the mapping project with the objective of achieving a solid, harmonious product.”

Video: Pedestrian Spatial Analysis

/ Matt Artz

“Spatial Analysis can be used pre simulation to estimate areas of highest probability of conflict or most wear and tear in the pedestrian space. Space utilisation values can be queried using the Spatial Metrics Tool within the Urban Analytics Framework (UAF) during or after simulation to see the actual effect of the available free space on the movement of agents. This tool is used to highlight where excessive density or high spatial utilisation values indicate a potential for crushing and injury as the crowd moves through the model.”

Geostatistical Analysis of Surface Soil Texture from Zala County in Western Hungary

/ Matt Artz

Proceedings of the International Symposium on Environment, Energy and Water in Nepal: Recent Researches and Direction for Future. 31 March – 01 April 2009, Hotel Himalaya, Kathmandu, Nepal

K. Adhikari, A. Guadagnini, G. Toth and T. Hermann. Pages 219 – 224

“Soil texture is one of the most important soil properties governing most of the physical, chemical and hydrological properties of soils. Variability in soil texture may contribute to the variation in nutrient storage and availability, water retention and transport and binding and stability of soil aggregates. It can directly or indirectly influence many other soil functions and soil threats such as soil erosion. Geostatistics has been extensively used for quantifying the spatial pattern of soil properties and Kriging techniques are proving sufficiently robust for estimating values at unsampled locations in most of the cases. In our study, we show the applicability of Ordinary Kriging techniques to characterize the spatial variation of soil texture i.e. sand and clay content on the basis of 100 samples collected over a forest mixed agriculture farming area covering about 250sq. km of Zala County in western Hungary. Our study supports the usefulness of geostatistical techniques to analyze the spatial distribution of soil texture content. The results (provided in terms of prediction maps and their associated variance) can be used as a source of information for the development and implementation of any further land management and soil and water conservation plans in the study area.”