Stefan Leyk
Dados Biográficos
| ID | 274123 |
|---|---|
| NOME | Stefan Leyk |
| PRENOMES | Stefan |
| SOBRENOME | Leyk |
| ASSINATURA | LEYK S |
| AFILIAÇÕES | University of Colorado Boulder |
| ORCID | 0000-0001-9180-4853 |
| VERIFICADO | Sim |
| TOTAL DE OBRAS | 24 |
| TOTAL DE CITAÇÕES | 45 |
| TOTAL COMO AUTOR | 24 |
| TOTAL COMO EDITOR | 0 |
| PRIMEIRO ANO DE PUBLICAÇÃO | 2009 |
| ANO MAIS RECENTE DE PUBLICAÇÃO | 2026 |
| ÍNDICE H | 4 |
The geometry of loss
Flood risk and the built environment
Analyzing urban scaling laws in the United States over 115 years
The scaling relations between city attributes and population are emergent and ubiquitous aspects of urban growth. Quantifying these relations and understanding their theoretical foundation, however, is difficult due to the challenge of defining city boundaries and a lack of historical data to study city dynamics over time and space. To address this issue, we analyze scaling between city infrastructure and population across 857 metropolitan areas …
Spatial poverty dynamics and social mobility in rural America
Rural America is often depicted as a distressed and left‐behind place, with limited opportunities for the children growing up there. This paper addresses this topic by examining the dynamics of rural places over the past four decades and how these changes impact the economic mobility of children raised in poor rural households. Employing a place‐based framework, we utilise sequence analysis to identify dominant trajectories of change for more tha…
Place-level urban–rural indices for the United States from 1930 to 2018
Using machine learning and data enrichment in the selection of roads for small-scale maps
Making decisions about which objects to keep or omit is challenging in map design. This process, called selection, constitutes the first operation in cartographic generalization. In this research, a method of automatic road selection for creating small-scale maps using machine learning and data enrichment is proposed. First, the problem of contextual information scarcity concerning roads in the source database is addressed. Additional information…
Geospatial Modeling Approaches to Historical Settlement and Landscape Analysis
Landscapes and human settlements evolve over long periods of time. Land change, as one of the drivers of the ecological crisis in the Anthropocene, therefore, needs to be studied with a long-term perspective. Over the past decades, a substantial body of research has accumulated in the field of land change science. The quantitative geospatial analysis of land change, however, still faces many challenges; be that methodological or data accessibilit…
Towards the automated large-scale reconstruction of past road networks from historical maps
Transportation infrastructure, such as road or railroad networks, represent a fundamental component of our civilization. For sustainable planning and informed decision making, a thorough understanding of the long-term evolution of transportation infrastructure such as road networks is crucial. However, spatially explicit, multi-temporal road network data covering large spatial extents are scarce and rarely available prior to the 2000s. Herein, we…
Road network evolution in the urban and rural United States since 1900
Fires that matter
Increasing fire impacts across North America are associated with climate and vegetation change, greater exposure through development expansion, and less-well studied but salient social vulnerabilities. We are at a critical moment in the contemporary human-fire relationship, with an urgent need to transition from emergency response to proactive measures that build sustainable communities, protect human health, and restore the use of fire necessary…
Change in U.S. Small Town Community Capitals, 1980–2010
How Entrenched Is the Spatial Structure of Inequality in Cities? Evidence from the Integration of Census and Housing Data for Denver from 1940 to 2016
How entrenched is the spatial structure of inequality in cities? Although recent discussions provide conflicting answers to this question, the absence of long-term, longitudinal neighborhood data curtails direct examination of the issue. Focusing on the city of Denver, we develop a new strategy for analyzing neighborhood dynamics from 1940 to the present day. Our analysis of these data reveals surprising persistence in the income rank of neighbor…
The spatial allocation of population
Population data represent an essential component in studies focusing on human–nature interrelationships, disaster risk assessment and environmental health. Several recent efforts have produced global- and continental-extent gridded population data which are becoming increasingly popular among various research communities. However, these data products, which are of very different characteristics and based on different modeling assumptions, have ne…
Internal and International Mobility as Adaptation to Climatic Variability in Contemporary Mexico
Migration provides a strategy for rural Mexican households to cope with, or adapt to, weather events and climatic variability. Yet prior studies on "environmental migration" in this context have not examined the differences between choices of internal (domestic) or international movement. In addition, much of the prior work relied on very coarse spatial scales to operationalize the environmental variables such as rainfall patterns. To overcome th…
Variation by Geographic Scale in the Migration-Environment Association
Scholarly understanding of human migration’s environmental dimensions has greatly advanced in the past several years, motivated in large part by public and policy dialogue around “climate migrants”. The research presented here advances current demographic scholarship both through its substantive interpretations and conclusions, as well as its methodological approach. We examine temporary rural South African outmigration as related to household-le…
Deriving Small Area Mortality Estimates Using a Probabilistic Reweighting Method
Small area health estimates are important for studying environmental exposure, disease transmission, and health outcomes at the local scale. Yet, to protect privacy, the majority of publicly available health data are aggregated within larger spatial units such as states or counties. This article describes a method to generate small area mortality estimates from individual microdata that are available only for larger geographic entities. The morta…
Exploring the impact of dasymetric refinement on spatiotemporal small area estimates
Comparing demographic small area estimates across multiple time periods is hindered by boundary changes in census enumeration units. Areal interpolation can resolve temporal incompatibilities, but underlying assumptions of uniform population density within units is sometimes flawed and results in distorted estimates. Dasymetric modeling refines spatial precision by limiting areal interpolation to the most likely residential areas. Here, a systema…
Dasymetric Modeling and Uncertainty
Dasymetric models increase the spatial resolution of population data by incorporating related ancillary data layers. The role of uncertainty in dasymetric modeling has not been fully addressed as of yet. Uncertainty is usually present because most population data are themselves uncertain, and/or the geographic processes that connect population and the ancillary data layers are not precisely known. A new dasymetric methodology - the Penalized Maxi…
Rural Outmigration, Natural Capital, and Livelihoods in South Africa
Rural households across the globe engage in both migration and natural resource use as components of livelihood strategies designed to meet household needs. Yet, migration scholars have only recently begun to regularly integrate environmental factors into empirical modelling efforts. To examine the migration‐environment association in rural South Africa, we use vegetation measures derived from satellite imagery combined with detailed demographic …
Establishing relationships between parcel data and land cover for demographic small area estimation
Dasymetric and other small area estimation methods often use land-cover data in order to refine the spatial resolution of population data. The attribute tables of these land-cover data, however, are often related only weakly to population distribution. Recent studies have examined the use of parcel data, but parcel data are not available in all places. Thus, it becomes useful to identify the links between parcel data and land-cover data so that l…
Validation of spatially allocated small area estimates for 1880 Census demography
This paper details the validation of a methodology which spatially allocates Census microdata to census tracts, based on known, aggregate tract population distributions. To protect confidentiality, public-use microdata contain no spatial identifiers other
Spatio-temporal Trends of Diarrheal Mortality of Children in Association with Hydrographic Regions of Brazil
In this paper, we analyze trends in average annual peak timing values (MPT) of pediatric mortality attributed to diarrheal disease in Brazil for the period 1979-1989 using a novel approach for environmental health risk studies, that is using natural boundaries instead of politically derived boundaries to define the unit of analysis (UOA). We evaluate the approach at varying spatial scales: (1) Country-wide based on observed Municipal level mortal…
Fuzzy Modeling of Geometric Textures for Identifying Archipelagos in Area-Patch Generalization
This paper describes a method to approach area-patch problems in model generalization using fuzzy set theory. The area-patch problem identifies polygons with the same semantics (feature code) but varying geometry and spatial distribution. Area-patch generalization can be understood as a pattern recognition problem with a variety of viable solutions, constrained by the purposes of the generalized output. The focus lies with identifying geometric t…
Extracting Composite Cartographic Area Features in Low-Quality Maps
We describe an extraction method for area features defined by composite cartographic element's and derived front historical, Manually produced maps of low graphical quality. Composite elements appear in many topographic maps of the 19th and 20th century which provide unique information about the landscape of the past. We develop a method from prior research for extracting forest areas from the historic Siegfried Map, on which they are represented…
Rural Outmigration, Natural Capital, and Livelihoods in South Africa
Rural households across the globe engage in both migration and natural resource use as components of livelihood strategies designed to meet household needs. Yet, migration scholars have only recently begun to regularly integrate environmental factors into empirical modelling efforts. To examine the migration‐environment association in rural South Africa, we use vegetation measures derived from satellite imagery combined with detailed demographic …
Internal and International Mobility as Adaptation to Climatic Variability in Contemporary Mexico
Migration provides a strategy for rural Mexican households to cope with, or adapt to, weather events and climatic variability. Yet prior studies on "environmental migration" in this context have not examined the differences between choices of internal (domestic) or international movement. In addition, much of the prior work relied on very coarse spatial scales to operationalize the environmental variables such as rainfall patterns. To overcome th…
How Entrenched Is the Spatial Structure of Inequality in Cities? Evidence from the Integration of Census and Housing Data for Denver from 1940 to 2016
How entrenched is the spatial structure of inequality in cities? Although recent discussions provide conflicting answers to this question, the absence of long-term, longitudinal neighborhood data curtails direct examination of the issue. Focusing on the city of Denver, we develop a new strategy for analyzing neighborhood dynamics from 1940 to the present day. Our analysis of these data reveals surprising persistence in the income rank of neighbor…
Dasymetric Modeling and Uncertainty
Dasymetric models increase the spatial resolution of population data by incorporating related ancillary data layers. The role of uncertainty in dasymetric modeling has not been fully addressed as of yet. Uncertainty is usually present because most population data are themselves uncertain, and/or the geographic processes that connect population and the ancillary data layers are not precisely known. A new dasymetric methodology - the Penalized Maxi…
Validation of spatially allocated small area estimates for 1880 Census demography
This paper details the validation of a methodology which spatially allocates Census microdata to census tracts, based on known, aggregate tract population distributions. To protect confidentiality, public-use microdata contain no spatial identifiers other
Exploring the impact of dasymetric refinement on spatiotemporal small area estimates
Comparing demographic small area estimates across multiple time periods is hindered by boundary changes in census enumeration units. Areal interpolation can resolve temporal incompatibilities, but underlying assumptions of uniform population density within units is sometimes flawed and results in distorted estimates. Dasymetric modeling refines spatial precision by limiting areal interpolation to the most likely residential areas. Here, a systema…
Establishing relationships between parcel data and land cover for demographic small area estimation
Dasymetric and other small area estimation methods often use land-cover data in order to refine the spatial resolution of population data. The attribute tables of these land-cover data, however, are often related only weakly to population distribution. Recent studies have examined the use of parcel data, but parcel data are not available in all places. Thus, it becomes useful to identify the links between parcel data and land-cover data so that l…
Using machine learning and data enrichment in the selection of roads for small-scale maps
Making decisions about which objects to keep or omit is challenging in map design. This process, called selection, constitutes the first operation in cartographic generalization. In this research, a method of automatic road selection for creating small-scale maps using machine learning and data enrichment is proposed. First, the problem of contextual information scarcity concerning roads in the source database is addressed. Additional information…
Change in U.S. Small Town Community Capitals, 1980–2010
Variation by Geographic Scale in the Migration-Environment Association
Scholarly understanding of human migration’s environmental dimensions has greatly advanced in the past several years, motivated in large part by public and policy dialogue around “climate migrants”. The research presented here advances current demographic scholarship both through its substantive interpretations and conclusions, as well as its methodological approach. We examine temporary rural South African outmigration as related to household-le…
Fuzzy Modeling of Geometric Textures for Identifying Archipelagos in Area-Patch Generalization
This paper describes a method to approach area-patch problems in model generalization using fuzzy set theory. The area-patch problem identifies polygons with the same semantics (feature code) but varying geometry and spatial distribution. Area-patch generalization can be understood as a pattern recognition problem with a variety of viable solutions, constrained by the purposes of the generalized output. The focus lies with identifying geometric t…
Extracting Composite Cartographic Area Features in Low-Quality Maps
We describe an extraction method for area features defined by composite cartographic element's and derived front historical, Manually produced maps of low graphical quality. Composite elements appear in many topographic maps of the 19th and 20th century which provide unique information about the landscape of the past. We develop a method from prior research for extracting forest areas from the historic Siegfried Map, on which they are represented…
Extracting Composite Cartographic Area Features in Low-Quality Maps
We describe an extraction method for area features defined by composite cartographic element's and derived front historical, Manually produced maps of low graphical quality. Composite elements appear in many topographic maps of the 19th and 20th century which provide unique information about the landscape of the past. We develop a method from prior research for extracting forest areas from the historic Siegfried Map, on which they are represented…
Spatio-temporal Trends of Diarrheal Mortality of Children in Association with Hydrographic Regions of Brazil
In this paper, we analyze trends in average annual peak timing values (MPT) of pediatric mortality attributed to diarrheal disease in Brazil for the period 1979-1989 using a novel approach for environmental health risk studies, that is using natural boundaries instead of politically derived boundaries to define the unit of analysis (UOA). We evaluate the approach at varying spatial scales: (1) Country-wide based on observed Municipal level mortal…
Fuzzy Modeling of Geometric Textures for Identifying Archipelagos in Area-Patch Generalization
This paper describes a method to approach area-patch problems in model generalization using fuzzy set theory. The area-patch problem identifies polygons with the same semantics (feature code) but varying geometry and spatial distribution. Area-patch generalization can be understood as a pattern recognition problem with a variety of viable solutions, constrained by the purposes of the generalized output. The focus lies with identifying geometric t…
Rural Outmigration, Natural Capital, and Livelihoods in South Africa
Rural households across the globe engage in both migration and natural resource use as components of livelihood strategies designed to meet household needs. Yet, migration scholars have only recently begun to regularly integrate environmental factors into empirical modelling efforts. To examine the migration‐environment association in rural South Africa, we use vegetation measures derived from satellite imagery combined with detailed demographic …
Establishing relationships between parcel data and land cover for demographic small area estimation
Dasymetric and other small area estimation methods often use land-cover data in order to refine the spatial resolution of population data. The attribute tables of these land-cover data, however, are often related only weakly to population distribution. Recent studies have examined the use of parcel data, but parcel data are not available in all places. Thus, it becomes useful to identify the links between parcel data and land-cover data so that l…
Validation of spatially allocated small area estimates for 1880 Census demography
This paper details the validation of a methodology which spatially allocates Census microdata to census tracts, based on known, aggregate tract population distributions. To protect confidentiality, public-use microdata contain no spatial identifiers other
Dasymetric Modeling and Uncertainty
Dasymetric models increase the spatial resolution of population data by incorporating related ancillary data layers. The role of uncertainty in dasymetric modeling has not been fully addressed as of yet. Uncertainty is usually present because most population data are themselves uncertain, and/or the geographic processes that connect population and the ancillary data layers are not precisely known. A new dasymetric methodology - the Penalized Maxi…
Exploring the impact of dasymetric refinement on spatiotemporal small area estimates
Comparing demographic small area estimates across multiple time periods is hindered by boundary changes in census enumeration units. Areal interpolation can resolve temporal incompatibilities, but underlying assumptions of uniform population density within units is sometimes flawed and results in distorted estimates. Dasymetric modeling refines spatial precision by limiting areal interpolation to the most likely residential areas. Here, a systema…
Internal and International Mobility as Adaptation to Climatic Variability in Contemporary Mexico
Migration provides a strategy for rural Mexican households to cope with, or adapt to, weather events and climatic variability. Yet prior studies on "environmental migration" in this context have not examined the differences between choices of internal (domestic) or international movement. In addition, much of the prior work relied on very coarse spatial scales to operationalize the environmental variables such as rainfall patterns. To overcome th…
Variation by Geographic Scale in the Migration-Environment Association
Scholarly understanding of human migration’s environmental dimensions has greatly advanced in the past several years, motivated in large part by public and policy dialogue around “climate migrants”. The research presented here advances current demographic scholarship both through its substantive interpretations and conclusions, as well as its methodological approach. We examine temporary rural South African outmigration as related to household-le…
Deriving Small Area Mortality Estimates Using a Probabilistic Reweighting Method
Small area health estimates are important for studying environmental exposure, disease transmission, and health outcomes at the local scale. Yet, to protect privacy, the majority of publicly available health data are aggregated within larger spatial units such as states or counties. This article describes a method to generate small area mortality estimates from individual microdata that are available only for larger geographic entities. The morta…
The spatial allocation of population
Population data represent an essential component in studies focusing on human–nature interrelationships, disaster risk assessment and environmental health. Several recent efforts have produced global- and continental-extent gridded population data which are becoming increasingly popular among various research communities. However, these data products, which are of very different characteristics and based on different modeling assumptions, have ne…
Change in U.S. Small Town Community Capitals, 1980–2010
How Entrenched Is the Spatial Structure of Inequality in Cities? Evidence from the Integration of Census and Housing Data for Denver from 1940 to 2016
How entrenched is the spatial structure of inequality in cities? Although recent discussions provide conflicting answers to this question, the absence of long-term, longitudinal neighborhood data curtails direct examination of the issue. Focusing on the city of Denver, we develop a new strategy for analyzing neighborhood dynamics from 1940 to the present day. Our analysis of these data reveals surprising persistence in the income rank of neighbor…
Geospatial Modeling Approaches to Historical Settlement and Landscape Analysis
Landscapes and human settlements evolve over long periods of time. Land change, as one of the drivers of the ecological crisis in the Anthropocene, therefore, needs to be studied with a long-term perspective. Over the past decades, a substantial body of research has accumulated in the field of land change science. The quantitative geospatial analysis of land change, however, still faces many challenges; be that methodological or data accessibilit…
Towards the automated large-scale reconstruction of past road networks from historical maps
Transportation infrastructure, such as road or railroad networks, represent a fundamental component of our civilization. For sustainable planning and informed decision making, a thorough understanding of the long-term evolution of transportation infrastructure such as road networks is crucial. However, spatially explicit, multi-temporal road network data covering large spatial extents are scarce and rarely available prior to the 2000s. Herein, we…
Road network evolution in the urban and rural United States since 1900
Fires that matter
Increasing fire impacts across North America are associated with climate and vegetation change, greater exposure through development expansion, and less-well studied but salient social vulnerabilities. We are at a critical moment in the contemporary human-fire relationship, with an urgent need to transition from emergency response to proactive measures that build sustainable communities, protect human health, and restore the use of fire necessary…
Place-level urban–rural indices for the United States from 1930 to 2018
Using machine learning and data enrichment in the selection of roads for small-scale maps
Making decisions about which objects to keep or omit is challenging in map design. This process, called selection, constitutes the first operation in cartographic generalization. In this research, a method of automatic road selection for creating small-scale maps using machine learning and data enrichment is proposed. First, the problem of contextual information scarcity concerning roads in the source database is addressed. Additional information…
Analyzing urban scaling laws in the United States over 115 years
The scaling relations between city attributes and population are emergent and ubiquitous aspects of urban growth. Quantifying these relations and understanding their theoretical foundation, however, is difficult due to the challenge of defining city boundaries and a lack of historical data to study city dynamics over time and space. To address this issue, we analyze scaling between city infrastructure and population across 857 metropolitan areas …
Spatial poverty dynamics and social mobility in rural America
Rural America is often depicted as a distressed and left‐behind place, with limited opportunities for the children growing up there. This paper addresses this topic by examining the dynamics of rural places over the past four decades and how these changes impact the economic mobility of children raised in poor rural households. Employing a place‐based framework, we utilise sequence analysis to identify dominant trajectories of change for more tha…
Flood risk and the built environment
The geometry of loss
Geography (21 obras) · Computer Science (14 obras) · Cartography (11 obras) · Land Use and Ecosystem Services (8 obras) · Population (8 obras) · Mathematics (7 obras) · Artificial Intelligence (6 obras) · Data mining (6 obras) · Economic geography (6 obras) · Economic growth (6 obras)