Search for: All records

ABSTRACT The OpenStreetMap (OSM) project allows volunteers in the community to contribute and manage spatial data collaboratively and provides free spatial data with global coverage to the public. OSM data have been widely used in many applications. However, the quality of OSM data can be inconsistent due to the crowdsourcing nature of the OSM project. This study compares the OSM road data with the national road data from the U.S. Census Topologically Integrated Geographic Encoding and Referencing system (TIGER) project in the contiguous United States. Specifically, we used three indicators to examine the completeness and positional accuracy of the OSM road data at the county level. Then we performed spatial analysis to study the patterns of the discrepancies. Our results show that OSM road data are inconsistent in completeness and positional accuracy across different counties. Finally, we compared the three indicators among metropolitan, nonmetropolitan, and rural counties with Analysis of Variance (ANOVA) and Boxplot. The results show that the OSM road data in metropolitan counties have better completeness and positional accuracy than those in nonmetropolitan and rural counties. This study can improve our understanding of the quality of OSM road data in the United States, which in turn can help the OSM community improve the quality of road data and allow data users to better use OSM road data in different applications. 

The increasing wildfire activity and rapid population growth in the wildland–urban interface (WUI) have made more Americans exposed to wildfire risk. WUI mapping plays a significant role in wildfire management. This study used the Microsoft building footprint (MBF) and the Montana address/structure framework datasets to map the WUI in Montana. A systematic comparison of the following three types of WUI was performed: the WUI maps derived from the Montana address/structure framework dataset (WUI-P), the WUI maps derived from the MBF dataset (WUI-S), and the Radeloff WUI map derived from census data (WUI-Z). The results show that WUI-S and WUI-P are greater than WUI-Z in the WUI area. Moreover, WUI-S has more WUI area than WUI-P due to the inclusion of all structures rather than just address points. Spatial analysis revealed clusters of high percentage WUI area in western Montana and low percentage WUI area in eastern Montana, which is likely related to a combination of factors including topography and population density. A web GIS application was also developed to facilitate the dissemination of the resulting WUI maps and allow visual comparison between the three WUI types. This study demonstrated that the MBF can be a useful resource for mapping the WUI and could be used in place of a national address point dataset. 

Bode integrals of sensitivity and sensitivity-like functions along with complementary sensitivity and complementary sensitivity-like functions are conventionally used for describing performance limitations of a feedback control system. In this paper, we show that in the case when the disturbance is a wide sense stationary process the (complementary) sensitivity Bode integral and the (complementary) sensitivity-like Bode integral are identical. A lower bound of the continuous-time complementary sensitivity-like Bode integral is also derived and examined with the linearized flight-path angle tracking control problem of an F-16 aircraft.