George Xian
Dr. George Xian is a research physical scientist with the U.S. Geological Survey, Earth Resources Observation and Science Center. He researches the national land cover data development, land cover change, and land cover change impacts on climate and ecosystems using remote sensing information.
George has specialized in using multi-type remote sensing data to characterize land change and change assessment across the United States. He has also used Landsat thermal information to study urban thermal landscape change by collaborating with other researchers from U.S. Global Change Research Program and universities. He also has participated in the development of U.S. Fifth National Climate Assessment.
Science and Products
Filter Total Items: 73
Effects of land cover and regional climate variations on long-term spatiotemporal changes in sagebrush ecosystems
This research investigated the effects of climate and land cover change on variation in sagebrush ecosystems. We combined information of multi-year sagebrush distribution derived from multitemporal remote sensing imagery and climate data to study the variation patterns of sagebrush ecosystems under different potential disturbances. We found that less than 40% of sagebrush ecosystem changes involve
Authors
George Z. Xian, Collin G. Homer, Cameron L. Aldridge
Assessing long-term variations in sagebrush habitat: characterization of spatial extents and distribution patterns using multi-temporal satellite remote-sensing data
An approach that can generate sagebrush habitat change estimates for monitoring large-area sagebrush ecosystems has been developed and tested in southwestern Wyoming, USA. This prototype method uses a satellite-based image change detection algorithm and regression models to estimate sub-pixel percentage cover for five sagebrush habitat components: bare ground, herbaceous, litter, sagebrush and shr
Authors
George Xian, Collin G. Homer, Cameron L. Aldridge
Quantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region
We estimated urbanization rates (2001–2006) in the Gulf of Mexico region using the National Land Cover Database (NLCD) 2001 and 2006 impervious surface products. An improved method was used to update the NLCD impervious surface product in 2006 and associated land cover transition between 2001 and 2006. Our estimation reveals that impervious surface increased 416 km2 with a growth rate of 5.8% betw
Authors
George Z. Xian, Collin G. Homer, Brett Bunde, Patrick Danielson, Jon Dewitz, Joyce Fry, Ruiliang Pu
Assessment of urbanization patterns and trends in the Gulf of Mexico region of the southeast United States with Landsat and nighttime lights imagery
No abstract available.
Authors
George Z. Xian, Collin G. Homer
Completion of the 2006 national land cover database for the conterminous united states
No abstract available.
Authors
Joyce Fry, George Z. Xian, Suming Jin, Jon Dewitz, Collin G. Homer, Limin Yang, Christopher A. Barnes, N.D. Herold, J.D. Wickham
Development of the USGS national land-cover database over two decades
Land-cover composition and change have profound impacts on terrestrial ecosystems. Land-cover and land-use (LCLU) conditions and their changes can affect social and physical environments by altering ecosystem conditions and services. Information about LCLU change is often used to produce landscape-based metrics and evaluate landscape conditions to monitor LCLU status and trends over a specific tim
Authors
George Z. Xian, Collin G. Homer, Limin Yang
Change of impervious surface area between 2001 and 2006 in the conterminous United States
No abstract available.
Authors
George Z. Xian, Collin G. Homer, Jon Dewitz, Joyce Fry, N. Hossain, J. Wickham
Updating the 2001 National Land Cover Database Impervious Surface Products to 2006 using Landsat imagery change detection methods
A prototype method was developed to update the U.S. Geological Survey (USGS) National Land Cover Database (NLCD) 2001 to a nominal date of 2006. NLCD 2001 is widely used as a baseline for national land cover and impervious cover conditions. To enable the updating of this database in an optimal manner, methods are designed to be accomplished by individual Landsat scene. Using conservative change th
Authors
George Xian, Collin G. Homer
Identifying 5 years of land cover change across the nation: Updating NLCD 2001 to 2006 through image change detection
No abstract available.
Authors
George Z. Xian, Collin G. Homer
Foreword to the issue on remote sensing of regional land use and land cover
This issue showcases some good work from Chinese authors who attended the International Workshop of Earth Observation and Remote Sensing Applications (EORSA), held in Beijing, China, June 30-July 2, 2008. The five articles in this issue focus on remote sensing of regional land use and land cover.
Authors
Qihao Weng, Jixian Zhang, P. Gamba, George Z. Xian
Monitoring urban land cover change by updating the national land cover database impervious surface products
The U.S. Geological Survey (USGS) National Land Cover Database (NLCD) 2001 is widely used as a baseline for national land cover and impervious conditions. To ensure timely and relevant data, it is important to update this base to a more recent time period. A prototype method was developed to update the land cover and impervious surface by individual Landsat path and row. This method updates NLCD 2
Authors
George Z. Xian, Collin G. Homer
Updating the 2001 National Land Cover Database land cover classification to 2006 by using Landsat imagery change detection methods
The recent release of the U.S. Geological Survey (USGS) National Land Cover Database (NLCD) 2001, which represents the nation's land cover status based on a nominal date of 2001, is widely used as a baseline for national land cover conditions. To enable the updating of this land cover information in a consistent and continuous manner, a prototype method was developed to update land cover by an ind
Authors
George Xian, Collin G. Homer, Joyce Fry
Science and Products
Filter Total Items: 73
Effects of land cover and regional climate variations on long-term spatiotemporal changes in sagebrush ecosystems
This research investigated the effects of climate and land cover change on variation in sagebrush ecosystems. We combined information of multi-year sagebrush distribution derived from multitemporal remote sensing imagery and climate data to study the variation patterns of sagebrush ecosystems under different potential disturbances. We found that less than 40% of sagebrush ecosystem changes involve
Authors
George Z. Xian, Collin G. Homer, Cameron L. Aldridge
Assessing long-term variations in sagebrush habitat: characterization of spatial extents and distribution patterns using multi-temporal satellite remote-sensing data
An approach that can generate sagebrush habitat change estimates for monitoring large-area sagebrush ecosystems has been developed and tested in southwestern Wyoming, USA. This prototype method uses a satellite-based image change detection algorithm and regression models to estimate sub-pixel percentage cover for five sagebrush habitat components: bare ground, herbaceous, litter, sagebrush and shr
Authors
George Xian, Collin G. Homer, Cameron L. Aldridge
Quantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region
We estimated urbanization rates (2001–2006) in the Gulf of Mexico region using the National Land Cover Database (NLCD) 2001 and 2006 impervious surface products. An improved method was used to update the NLCD impervious surface product in 2006 and associated land cover transition between 2001 and 2006. Our estimation reveals that impervious surface increased 416 km2 with a growth rate of 5.8% betw
Authors
George Z. Xian, Collin G. Homer, Brett Bunde, Patrick Danielson, Jon Dewitz, Joyce Fry, Ruiliang Pu
Assessment of urbanization patterns and trends in the Gulf of Mexico region of the southeast United States with Landsat and nighttime lights imagery
No abstract available.
Authors
George Z. Xian, Collin G. Homer
Completion of the 2006 national land cover database for the conterminous united states
No abstract available.
Authors
Joyce Fry, George Z. Xian, Suming Jin, Jon Dewitz, Collin G. Homer, Limin Yang, Christopher A. Barnes, N.D. Herold, J.D. Wickham
Development of the USGS national land-cover database over two decades
Land-cover composition and change have profound impacts on terrestrial ecosystems. Land-cover and land-use (LCLU) conditions and their changes can affect social and physical environments by altering ecosystem conditions and services. Information about LCLU change is often used to produce landscape-based metrics and evaluate landscape conditions to monitor LCLU status and trends over a specific tim
Authors
George Z. Xian, Collin G. Homer, Limin Yang
Change of impervious surface area between 2001 and 2006 in the conterminous United States
No abstract available.
Authors
George Z. Xian, Collin G. Homer, Jon Dewitz, Joyce Fry, N. Hossain, J. Wickham
Updating the 2001 National Land Cover Database Impervious Surface Products to 2006 using Landsat imagery change detection methods
A prototype method was developed to update the U.S. Geological Survey (USGS) National Land Cover Database (NLCD) 2001 to a nominal date of 2006. NLCD 2001 is widely used as a baseline for national land cover and impervious cover conditions. To enable the updating of this database in an optimal manner, methods are designed to be accomplished by individual Landsat scene. Using conservative change th
Authors
George Xian, Collin G. Homer
Identifying 5 years of land cover change across the nation: Updating NLCD 2001 to 2006 through image change detection
No abstract available.
Authors
George Z. Xian, Collin G. Homer
Foreword to the issue on remote sensing of regional land use and land cover
This issue showcases some good work from Chinese authors who attended the International Workshop of Earth Observation and Remote Sensing Applications (EORSA), held in Beijing, China, June 30-July 2, 2008. The five articles in this issue focus on remote sensing of regional land use and land cover.
Authors
Qihao Weng, Jixian Zhang, P. Gamba, George Z. Xian
Monitoring urban land cover change by updating the national land cover database impervious surface products
The U.S. Geological Survey (USGS) National Land Cover Database (NLCD) 2001 is widely used as a baseline for national land cover and impervious conditions. To ensure timely and relevant data, it is important to update this base to a more recent time period. A prototype method was developed to update the land cover and impervious surface by individual Landsat path and row. This method updates NLCD 2
Authors
George Z. Xian, Collin G. Homer
Updating the 2001 National Land Cover Database land cover classification to 2006 by using Landsat imagery change detection methods
The recent release of the U.S. Geological Survey (USGS) National Land Cover Database (NLCD) 2001, which represents the nation's land cover status based on a nominal date of 2001, is widely used as a baseline for national land cover conditions. To enable the updating of this land cover information in a consistent and continuous manner, a prototype method was developed to update land cover by an ind
Authors
George Xian, Collin G. Homer, Joyce Fry