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: 74
Methods for converting continuous shrubland ecosystem component values to thematic National Land Cover Database classes
The National Land Cover Database (NLCD) provides thematic land cover and land cover change data at 30-meter spatial resolution for the United States. Although the NLCD is considered to be the leading thematic land cover/land use product and overall classification accuracy across the NLCD is high, performance and consistency in the vast shrub and grasslands of the Western United States is lower tha
Authors
Matthew B. Rigge, Leila Gass, Collin G. Homer, George Z. Xian
Decadal shifts in grass and woody plant cover are driven by prolonged drying and modified by topo‐edaphic properties
Woody plant encroachment and overall declines in perennial vegetation in dryland regions can alter ecosystem properties and indicate land degradation, but the causes of these shifts remain controversial. Determining how changes in the abundance and distribution of grass and woody plants are influenced by conditions that regulate water availability at a regional scale provides a baseline to compare
Authors
Seth M. Munson, Temuulen T. Sankey, George Z. Xian, Miguel L. Villarreal, Collin G. Homer
Mapping annual forest cover in sub-humid and semi-arid regions through analysis of landsat and PALSAR imagery
Accurately mapping the spatial distribution of forests in sub-humid to semi-arid regions over years is a challenging task and causes difficulty to forest management. Relatively large uncertainties still exist in the spatial distribution of forests and deforestation in the sub-humid and semi-arid regions. Numerous publications have used either optical or synthetic aperture radar (SAR) remote sensin
Authors
Yuanwei Qin, Xiangming Xiao, Jie Wang, Jinwei Dong, Kayti Ewing, Bruce Hoagland, Daniel J Hough, Todd D Fagin, Zhenhua Zou, George L. Geissler, George Z. Xian, Thomas Loveland
Regional differences in upland forest to developed (urban) land cover conversions in the conterminous U.S., 1973–2011
In this U.S. Geological Survey study of forest land cover across the conterminous U.S. (CONUS), specific proportions and rates of forest conversion to developed (urban) land were assessed on an ecoregional basis. The study period was divided into six time intervals between 1973 and 2011. Forest land cover was the source of 40% or more of the new urban land in 35 of the 84 ecoregions located within
Authors
Roger F. Auch, Mark A. Drummond, George Z. Xian, Kristi Sayler, William Acevedo, Janis Taylor
Characterization of shrubland ecosystem components as continuous fields in the northwest United States
Accurate and consistent estimates of shrubland ecosystem components are crucial to a better understanding of ecosystem conditions in arid and semiarid lands. An innovative approach was developed by integrating multiple sources of information to quantify shrubland components as continuous field products within the National Land Cover Database (NLCD). The approach consists of several procedures incl
Authors
George Z. Xian, Collin G. Homer, Matthew B. Rigge, Hua Shi, Debbie Meyer
Forecasting sagebrush ecosystem components and greater sage-grouse habitat for 2050: learning from past climate patterns and Landsat imagery to predict the future
Sagebrush (Artemisia spp.) ecosystems constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. Disturbances have altered and reduced this ecosystem historically, but climate change may ultimately represent the greatest future risk. Improved ways to quantify, monitor, and predict climate-d
Authors
Collin G. Homer, George Z. Xian, Cameron L. Aldridge, Debra K. Meyer, Thomas R. Loveland, Michael S. O'Donnell
Completion of the 2011 National Land Cover Database for the conterminous United States – Representing a decade of land cover change information
The National Land Cover Database (NLCD) provides nationwide data on land cover and land cover change at the native 30-m spatial resolution of the Landsat Thematic Mapper (TM). The database is designed to provide five-year cyclical updating of United States land cover and associated changes. The recent release of NLCD 2011 products now represents a decade of consistently produced land cover and imp
Authors
Collin G. Homer, Jon Dewitz, Limin Yang, Suming Jin, Patrick Danielson, George Z. Xian, John Coulston, Nathaniel Herold, James Wickham, Kevin Megown
Application of spatially gridded temperature and land cover data sets for urban heat island analysis
Two gridded data sets that included (1) daily mean temperatures from 2006 through 2011 and (2) satellite-derived impervious surface area, were combined for a spatial analysis of the urban heat-island effect within the Dallas-Ft. Worth Texas region. The primary advantage of using these combined datasets included the capability to designate each 1 × 1 km grid cell of available temperature data as ur
Authors
Kevin Gallo, George Z. Xian
An approach for characterizing the distribution of shrubland ecosystem components as continuous fields as part of NLCD
Characterizing and quantifying distributions of shrubland ecosystem components is one of the major challenges for monitoring shrubland vegetation cover change across the United States. A new approach has been developed to quantify shrubland components as fractional products within National Land Cover Database (NLCD). This approach uses remote sensing data and regression tree models to estimate the
Authors
George Z. Xian, Collin G. Homer, Debbie Meyer, Brian J. Granneman
Automated cloud and shadow detection and filling using two-date Landsat imagery in the United States
A simple, efficient, and practical approach for detecting cloud and shadow areas in satellite imagery and restoring them with clean pixel values has been developed. Cloud and shadow areas are detected using spectral information from the blue, shortwave infrared, and thermal infrared bands of Landsat Thematic Mapper or Enhanced Thematic Mapper Plus imagery from two dates (a target image and a refer
Authors
Suming Jin, Collin G. Homer, Limin Yang, George Xian, Joyce Fry, Patrick Danielson, Philip A. Townsend
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 between 2001 and
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
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 has been
Authors
George Xian, Collin G. Homer, Brian Granneman, Debra K. Meyer
Science and Products
Filter Total Items: 74
Methods for converting continuous shrubland ecosystem component values to thematic National Land Cover Database classes
The National Land Cover Database (NLCD) provides thematic land cover and land cover change data at 30-meter spatial resolution for the United States. Although the NLCD is considered to be the leading thematic land cover/land use product and overall classification accuracy across the NLCD is high, performance and consistency in the vast shrub and grasslands of the Western United States is lower tha
Authors
Matthew B. Rigge, Leila Gass, Collin G. Homer, George Z. Xian
Decadal shifts in grass and woody plant cover are driven by prolonged drying and modified by topo‐edaphic properties
Woody plant encroachment and overall declines in perennial vegetation in dryland regions can alter ecosystem properties and indicate land degradation, but the causes of these shifts remain controversial. Determining how changes in the abundance and distribution of grass and woody plants are influenced by conditions that regulate water availability at a regional scale provides a baseline to compare
Authors
Seth M. Munson, Temuulen T. Sankey, George Z. Xian, Miguel L. Villarreal, Collin G. Homer
Mapping annual forest cover in sub-humid and semi-arid regions through analysis of landsat and PALSAR imagery
Accurately mapping the spatial distribution of forests in sub-humid to semi-arid regions over years is a challenging task and causes difficulty to forest management. Relatively large uncertainties still exist in the spatial distribution of forests and deforestation in the sub-humid and semi-arid regions. Numerous publications have used either optical or synthetic aperture radar (SAR) remote sensin
Authors
Yuanwei Qin, Xiangming Xiao, Jie Wang, Jinwei Dong, Kayti Ewing, Bruce Hoagland, Daniel J Hough, Todd D Fagin, Zhenhua Zou, George L. Geissler, George Z. Xian, Thomas Loveland
Regional differences in upland forest to developed (urban) land cover conversions in the conterminous U.S., 1973–2011
In this U.S. Geological Survey study of forest land cover across the conterminous U.S. (CONUS), specific proportions and rates of forest conversion to developed (urban) land were assessed on an ecoregional basis. The study period was divided into six time intervals between 1973 and 2011. Forest land cover was the source of 40% or more of the new urban land in 35 of the 84 ecoregions located within
Authors
Roger F. Auch, Mark A. Drummond, George Z. Xian, Kristi Sayler, William Acevedo, Janis Taylor
Characterization of shrubland ecosystem components as continuous fields in the northwest United States
Accurate and consistent estimates of shrubland ecosystem components are crucial to a better understanding of ecosystem conditions in arid and semiarid lands. An innovative approach was developed by integrating multiple sources of information to quantify shrubland components as continuous field products within the National Land Cover Database (NLCD). The approach consists of several procedures incl
Authors
George Z. Xian, Collin G. Homer, Matthew B. Rigge, Hua Shi, Debbie Meyer
Forecasting sagebrush ecosystem components and greater sage-grouse habitat for 2050: learning from past climate patterns and Landsat imagery to predict the future
Sagebrush (Artemisia spp.) ecosystems constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. Disturbances have altered and reduced this ecosystem historically, but climate change may ultimately represent the greatest future risk. Improved ways to quantify, monitor, and predict climate-d
Authors
Collin G. Homer, George Z. Xian, Cameron L. Aldridge, Debra K. Meyer, Thomas R. Loveland, Michael S. O'Donnell
Completion of the 2011 National Land Cover Database for the conterminous United States – Representing a decade of land cover change information
The National Land Cover Database (NLCD) provides nationwide data on land cover and land cover change at the native 30-m spatial resolution of the Landsat Thematic Mapper (TM). The database is designed to provide five-year cyclical updating of United States land cover and associated changes. The recent release of NLCD 2011 products now represents a decade of consistently produced land cover and imp
Authors
Collin G. Homer, Jon Dewitz, Limin Yang, Suming Jin, Patrick Danielson, George Z. Xian, John Coulston, Nathaniel Herold, James Wickham, Kevin Megown
Application of spatially gridded temperature and land cover data sets for urban heat island analysis
Two gridded data sets that included (1) daily mean temperatures from 2006 through 2011 and (2) satellite-derived impervious surface area, were combined for a spatial analysis of the urban heat-island effect within the Dallas-Ft. Worth Texas region. The primary advantage of using these combined datasets included the capability to designate each 1 × 1 km grid cell of available temperature data as ur
Authors
Kevin Gallo, George Z. Xian
An approach for characterizing the distribution of shrubland ecosystem components as continuous fields as part of NLCD
Characterizing and quantifying distributions of shrubland ecosystem components is one of the major challenges for monitoring shrubland vegetation cover change across the United States. A new approach has been developed to quantify shrubland components as fractional products within National Land Cover Database (NLCD). This approach uses remote sensing data and regression tree models to estimate the
Authors
George Z. Xian, Collin G. Homer, Debbie Meyer, Brian J. Granneman
Automated cloud and shadow detection and filling using two-date Landsat imagery in the United States
A simple, efficient, and practical approach for detecting cloud and shadow areas in satellite imagery and restoring them with clean pixel values has been developed. Cloud and shadow areas are detected using spectral information from the blue, shortwave infrared, and thermal infrared bands of Landsat Thematic Mapper or Enhanced Thematic Mapper Plus imagery from two dates (a target image and a refer
Authors
Suming Jin, Collin G. Homer, Limin Yang, George Xian, Joyce Fry, Patrick Danielson, Philip A. Townsend
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 between 2001 and
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
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 has been
Authors
George Xian, Collin G. Homer, Brian Granneman, Debra K. Meyer