George Xian (Former Employee)
Science and Products
Filter Total Items: 77
A comprehensive change detection method for updating the National Land Cover Database to circa 2011 A comprehensive change detection method for updating the National Land Cover Database to circa 2011
The importance of characterizing, quantifying, and monitoring land cover, land use, and their changes has been widely recognized by global and environmental change studies. Since the early 1990s, three U.S. National Land Cover Database (NLCD) products (circa 1992, 2001, and 2006) have been released as free downloads for users. The NLCD 2006 also provides land cover change products...
Authors
Suming Jin, Limin Yang, Patrick Danielson, Collin G. Homer, Joyce Fry, George Xian
Producing fractional rangeland component predictions in a sagebrush ecosystem, a Wyoming sensitivity analysis Producing fractional rangeland component predictions in a sagebrush ecosystem, a Wyoming sensitivity analysis
Remote sensing information has been widely used to monitor vegetation condition and variations in a variety of ecosystems, including shrublands. Careful application of remotely sensed imagery can provide additional spatially explicit, continuous, and extensive data on the composition and condition of shrubland ecosystems. Historically, the most widely available remote sensing information...
Authors
George Xian, Collin G. Homer, Brian Granneman, Debra K. Meyer
Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems
The focus of the study was to assess gradual changes occurring throughout a range of natural ecosystems using decadal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM +) time series data. Time series data stacks were generated for four study areas: (1) a four scene area dominated by forest and rangeland ecosystems in the southwestern United States, (2) a sagebrush...
Authors
James E. Vogelmann, George Xian, Collin G. Homer, Brian Tolk
Effects of land cover and regional climate variations on long-term spatiotemporal changes in sagebrush ecosystems 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...
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 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...
Authors
George Xian, Collin G. Homer, Cameron L. Aldridge
Quantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region 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...
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 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
Development of the USGS national land-cover database over two decades 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...
Authors
George Z. Xian, Collin G. Homer, Limin Yang
Completion of the 2006 national land cover database for the conterminous united states 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
Change of impervious surface area between 2001 and 2006 in the conterminous United States 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 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...
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 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
Science and Products
Filter Total Items: 77
A comprehensive change detection method for updating the National Land Cover Database to circa 2011 A comprehensive change detection method for updating the National Land Cover Database to circa 2011
The importance of characterizing, quantifying, and monitoring land cover, land use, and their changes has been widely recognized by global and environmental change studies. Since the early 1990s, three U.S. National Land Cover Database (NLCD) products (circa 1992, 2001, and 2006) have been released as free downloads for users. The NLCD 2006 also provides land cover change products...
Authors
Suming Jin, Limin Yang, Patrick Danielson, Collin G. Homer, Joyce Fry, George Xian
Producing fractional rangeland component predictions in a sagebrush ecosystem, a Wyoming sensitivity analysis Producing fractional rangeland component predictions in a sagebrush ecosystem, a Wyoming sensitivity analysis
Remote sensing information has been widely used to monitor vegetation condition and variations in a variety of ecosystems, including shrublands. Careful application of remotely sensed imagery can provide additional spatially explicit, continuous, and extensive data on the composition and condition of shrubland ecosystems. Historically, the most widely available remote sensing information...
Authors
George Xian, Collin G. Homer, Brian Granneman, Debra K. Meyer
Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems
The focus of the study was to assess gradual changes occurring throughout a range of natural ecosystems using decadal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM +) time series data. Time series data stacks were generated for four study areas: (1) a four scene area dominated by forest and rangeland ecosystems in the southwestern United States, (2) a sagebrush...
Authors
James E. Vogelmann, George Xian, Collin G. Homer, Brian Tolk
Effects of land cover and regional climate variations on long-term spatiotemporal changes in sagebrush ecosystems 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...
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 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...
Authors
George Xian, Collin G. Homer, Cameron L. Aldridge
Quantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region 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...
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 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
Development of the USGS national land-cover database over two decades 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...
Authors
George Z. Xian, Collin G. Homer, Limin Yang
Completion of the 2006 national land cover database for the conterminous united states 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
Change of impervious surface area between 2001 and 2006 in the conterminous United States 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 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...
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 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