The paper presents an algorithm for constructing geometric buffers for vector feature layers and dissolving those buffers using a sweep-line approach and vector algebra.The algorithm works by first constructing a geom...The paper presents an algorithm for constructing geometric buffers for vector feature layers and dissolving those buffers using a sweep-line approach and vector algebra.The algorithm works by first constructing a geometric buffer for a vector feature layer,then dissolving each single geometric buffer for that feature layer,and finally dissolving the overlapping buffers of the entire layer.The algorithm has been implemented successfully in a commercial Geographical Information System software package.展开更多
The transformation from authoritative to user-generated data landscapes has garnered considerable attention,notably with the proliferation of crowdsourced geospatial data.Facilitated by advancements in digital technol...The transformation from authoritative to user-generated data landscapes has garnered considerable attention,notably with the proliferation of crowdsourced geospatial data.Facilitated by advancements in digital technology and high-speed communication,this paradigm shift has democratized data collection,obliterating traditional barriers between data producers and users.While previous literature has compartmentalized this subject into distinct platforms and application domains,this review offers a holistic examination of crowdsourced geospatial data.Employing a narrative review approach due to the interdisciplinary nature of the topic,we investigate both human and Earth observations through crowdsourced initiatives.This review categorizes the diverse applications of these data and rigorously examines specific platforms and paradigms pertinent to data collection.Furthermore,it addresses salient challenges,encompassing data quality,inherent biases,and ethical dimensions.We contend that this thorough analysis will serve as an invaluable scholarly resource,encapsulating the current state-of-the-art in crowdsourced geospatial data,and offering strategic directions for future interdisciplinary research and applications across various sectors.展开更多
Irrigation consumes three quarters of globalwater withdrawals each year. Strategies are needed toreduce irrigationwater use, including increasingtheefficiency of transfer methods and field application.Comprehensive re...Irrigation consumes three quarters of globalwater withdrawals each year. Strategies are needed toreduce irrigationwater use, including increasingtheefficiency of transfer methods and field application.Comprehensive restoration of soil health, specificallythrough organic matter amendments, can substantiallyreduce irrigation demand and increase crop yield. Aprogram to restore severely degraded and desertified soilsby incorporating coarse woodchips into the soil success-fully increased rainfall capture and elevated soil moisturefor several weeks between rainfall events at both Ningxia,north-west China and North Dakota, USA. With additionof fertilizer, woodchip incorporation further increasedgrowth of wheat and alfalfa. Comprehensive soil healthassessment of remnant grasslands was used to developtarget reference soil profiles by which to guide restorationefforts. Given that most agricultural soils are degraded tosome degree, soil health restoration can provide a powerfulstrategy toward achieving global food and water security.展开更多
文摘The paper presents an algorithm for constructing geometric buffers for vector feature layers and dissolving those buffers using a sweep-line approach and vector algebra.The algorithm works by first constructing a geometric buffer for a vector feature layer,then dissolving each single geometric buffer for that feature layer,and finally dissolving the overlapping buffers of the entire layer.The algorithm has been implemented successfully in a commercial Geographical Information System software package.
基金supported by the Faculty Startup Fund of the College of Arts and Sciences at Emory University.
文摘The transformation from authoritative to user-generated data landscapes has garnered considerable attention,notably with the proliferation of crowdsourced geospatial data.Facilitated by advancements in digital technology and high-speed communication,this paradigm shift has democratized data collection,obliterating traditional barriers between data producers and users.While previous literature has compartmentalized this subject into distinct platforms and application domains,this review offers a holistic examination of crowdsourced geospatial data.Employing a narrative review approach due to the interdisciplinary nature of the topic,we investigate both human and Earth observations through crowdsourced initiatives.This review categorizes the diverse applications of these data and rigorously examines specific platforms and paradigms pertinent to data collection.Furthermore,it addresses salient challenges,encompassing data quality,inherent biases,and ethical dimensions.We contend that this thorough analysis will serve as an invaluable scholarly resource,encapsulating the current state-of-the-art in crowdsourced geospatial data,and offering strategic directions for future interdisciplinary research and applications across various sectors.
文摘Irrigation consumes three quarters of globalwater withdrawals each year. Strategies are needed toreduce irrigationwater use, including increasingtheefficiency of transfer methods and field application.Comprehensive restoration of soil health, specificallythrough organic matter amendments, can substantiallyreduce irrigation demand and increase crop yield. Aprogram to restore severely degraded and desertified soilsby incorporating coarse woodchips into the soil success-fully increased rainfall capture and elevated soil moisturefor several weeks between rainfall events at both Ningxia,north-west China and North Dakota, USA. With additionof fertilizer, woodchip incorporation further increasedgrowth of wheat and alfalfa. Comprehensive soil healthassessment of remnant grasslands was used to developtarget reference soil profiles by which to guide restorationefforts. Given that most agricultural soils are degraded tosome degree, soil health restoration can provide a powerfulstrategy toward achieving global food and water security.
