New paper: Bridging the information gap: A webGIS tool for rural electrification in data-scarce regions

Müller, M F, S E Thompson, and M Kelly. 2016. Bridging the information gap: A webGIS tool for rural electrification in data-scarce regions. Applied Energy 171(1): 277-286

Rural electrification in developing countries is often hampered by major information gaps between local communities and urban centers, where technical expertise and fund- ing are concentrated. The tool presented in this paper addresses these gaps to support the implementation of off-grid micro hydropower infrastructure. Specifically, we present a method to site, size and evaluate the potential for micro hydropower based on re- mote sensing data. The method improves on previous approaches by (i) incorporating the effect of hillslope topography on the optimal layout of the infrastructure, and (ii) accounting for the constraints imposed by streamflow variability and local electricity demand on the optimal size of the plants. An assessment of the method’s performance against 148 existing schemes indicates that it correctly identifies the most promising locations for hydropower in Nepal, but does not generally reproduce the specific design features of constructed plants, which are affected by site-specific constraints. We develop a proof-of-concept computer tool to explore the potential of webGIS technology to account for these constraints by collecting site-specitic information from local users. Journal link. 

Keywords: Micro hydropower, WebGIS, Nepal, DEM 

Food vendors, neighborhood deprivation, and BMI

Zhang, YT, BA Laraia, MS Mujahid, A Tamayo, SD Blanchard, EM Warton, NM Kelly, HH Moffet, D Schillinger, N Adler, and AJ Karter. 2015. Does food vendor density mediate the association between neighborhood deprivation and BMI?: A G-computation mediation analysis. Epidemiology 26(3):344-52

In previous research, neighborhood deprivation was positively associated with body mass index (BMI) among adults with diabetes. We assessed whether the association between neighborhood deprivation and BMI is attributable, in part, to geographic variation in the availability of healthful and unhealthful food vendors. Subjects were 16,634 participants of the Diabetes Study of Northern California. Neighborhood deprivation and healthful (supermarket and produce) and unhealthful (fast food outlets and convenience stores) food vendor kernel density were calculated at each participant's residential block centroid. Availability of food vendors, both healthful and unhealthful, did not appear to explain the association between neighborhood deprivation and BMI in this population of adults with diabetes.

Click to read more ...

20th-century shifts in forest structure in California - evidence from the VTM dataset

McIntyre, P. J., J. H. Thorne, C. R. Dolanc, A. L. Flint, L. E. Flint, M. Kelly and D. D. Ackerly. 2015. Twentieth-century shifts in forest structure in California: Denser forests, smaller trees, and increased dominance of oaks. Proceedings of the National Academy of Sciences 112(5): 1458-1463

change in climate water deficit (left) and change in large trees (right)We document changes in forest structure between historical (1930s) and contemporary (2000s) surveys of California vegetation through comparisons of tree abundance and size across the state and within several ecoregions. Across California, tree density in forested regions increased by 30% between the two time periods, whereas forest biomass in the same regions declined, as indicated by a 19% reduction in basal area. These changes reflect a demographic shift in forest structure: larger trees (>60 cm diameter at breast height) have declined, whereas smaller trees (<30 cm) have increased. Large tree declines were more severe in areas experiencing greater increases in climatic water deficit since the 1930s, based on a hydrologicmodel of water balance for historical climates through the 20th century.

Click to read more ...

Agave production as a bioenergy feedstock: a fuzzy GIS model

Fuzzy GIS model for A. tequilaLewis, S., S. Gross, A. Visel, M. Kelly, and W. Morrow. 2015. Fuzzy GIS-based multi-criteria evaluation for U.S. Agave production as a bioenergy feedstock. Global Change Biology - Bioenergy 7:84–99. doi: 10.1111/gcbb.12116

In the United States, renewable energy mandates calling for increased production of cellulosic biofuels will require a diversity of bioenergy feedstocks to meet growing demands. Within the suite of potential energy crops, plants within the genus Agave promise to be a productive feedstock in hot and arid regions. The potential distributions of Agave tequilana and Agave deserti in the United States were evaluated based on plant growth parameters identified in an extensive literature review. A geospatial suitability model rooted in fuzzy logic was developed that utilized a suite of biophysical criteria to optimize ideal geographic locations for this new crop, and several suitability scenarios were tested for each species. The results of this spatially explicit suitability model suggest that there is potential for Agave to be grown as an energy feedstock in the southwestern region of the United States – particularly in Arizona, California, and Texas – and a significant portion of these areas are proximate to existing transportation infrastructure.

Click to read more ...

in biofuels, gis, lulc, modeling, rangelands

Tuesday

Dec092014

Spatial pattern of BMI among adults in Northern California 

Tuesday, December 9, 2014 at 8:41AM

Laraia, B. A., S. D. Blanchard, A. J. Karter, J. C. Jones-Smith, M. Warton, E. Kersten, M. Jerrett, H. H. Moffet, N. Adler, D. Schillinger, and M. Kelly. 2014. Spatial pattern of Body Mass Index among adults in the Diabetes Study of Northern California (DISTANCE). International Journal of Health Geographics 13:48 doi:10.1186/1476-072X-13-48

clustering of high and low BMIThe role that environmental factors, such as neighborhood socioeconomics, food, and physical environment, play in the risk of obesity and chronic diseases is not well quantified. Understanding how spatial distribution of disease risk factors overlap with that of environmental (contextual) characteristics may inform health interventions and policies aimed at reducing the environment risk factors.

Click to read more ...

in gis, health, open access, pattern, spatial analysis

Monday

Mar312014

What is "marginal land"? a review of the ways GIS is used to model (and define) "marginal land" for biofuel production

Monday, March 31, 2014 at 8:20AM

Lewis, S. and M. Kelly. 2014. Mapping the potential for biofuel production on marginal lands: differences in definitions, data and models across scale. International Journal of Geo-Information 3(2), 430-459; doi:10.3390/ijgi3020430

As energy policies mandate increases in bioenergy production, new research supports growing bioenergy feedstocks on marginal lands. Subsequently there has been an increase in published work that uses Geographic Information Systems (GIS) to map the availability of marginal land as a proxy for bioenergy crop potential. However, despite the similarity in stated intent among these works a number of inconsistencies remain across studies that make comparisons and standardization difficult. We reviewed a collection of recent literature that mapped bioenergy potential on marginal lands at varying scales, and found that there is no common working definition of marginal land across all of these works. Specifically we found considerable differences in mapped results that are driven by dissimilarities in definitions, model framework, data inputs, scale and treatment of uncertainty.

Click to read more ...

in biofuels, error, gis, modeling, open access, spatial analysis

Thursday

Mar062014

Mapping potential for switchgrass as a biofuel in the US

Thursday, March 6, 2014 at 8:19PM

One model outcome from the analysis.Lewis, S.M., G. Fitts, M. Kelly, L. Dale. 2014. A fuzzy logic-based spatial suitability model for drought-tolerant switchgrass in the United States. Computers and Electronics in Agriculture 103:39-47

Switchgrass (Panicum virgatum) has been targeted by the U.S. Department of Agriculture as an exemplary bioenergy crop, however it requires a significant amount of water and experiences reduced yields in water-stressed conditions. To avoid competition for prime agricultural areas, lands that receive adequate rainfall but are marginal due to highly variable timing of rain are potentially ideal locations to grow drought-tolerant biofuels. As scientists develop a modified variety of switchgrass that can withstand periods of drought while not substantially affecting overall yield, it is important to identify the potential geographical niche for this xerophytic crop to maximize its environmental and economic sustainability. This project uses a spatial suitability modeling approach that incorporates fuzzy logic and utilizes both physical and economic variables.

Click to read more ...

in biofuels, gis, modeling

Friday

Feb142014

SLR and wetlands in the SF Bay

Friday, February 14, 2014 at 1:19PM

The resilience of four marshes examined in this paper.Schile, L.M., J.C. Callaway, J.T. Morris, D. Stralberg, V. T. Parker, and M. Kelly. 2014. Modeling tidal marsh distribution with sea-level rise: evaluating the role of vegetation and upland habitat in marsh resiliency. PLOS One 9(2): e88760

Tidal marshes maintain elevation relative to sea level through accumulation of mineral and organic matter, yet this dynamic accumulation feedback mechanism has not been modeled widely in the context of accelerated sea-level rise. Uncertainties exist about tidal marsh resiliency to accelerated sea-level rise, reduced sediment supply, reduced plant productivity under increased inundation, and limited upland habitat for marsh migration. We examined marsh resiliency under these uncertainties using the Marsh Equilibrium Model, a mechanistic, elevation-based soil cohort model, using a rich data set of plant productivity and physical properties from sites across the estuarine salinity gradient. Four tidal marshes were chosen along this gradient: two islands and two with adjacent uplands. Varying century sea-level rise (52, 100, 165, 180 cm) and suspended sediment concentrations (100%, 50%, and 25% of current concentrations), we simulated marsh accretion across vegetated elevations for 100 years, applying the results to high spatial resolution digital elevation models to quantify potential changes in marsh distributions.

Click to read more ...

in gis, modeling, open access, wetlands

Sunday

May052013

Income and ethnicity differences among people with diabetes

Sunday, May 5, 2013 at 8:12PM

Jones Smith, J. C., M. Wharton, M. Kelly, E. Kersten, A. Karter, N. Adler, D. Schillinger, H. Moffett, B. A. Laraia. 2013. Obesity and the food environment: income and ethnicity differences among people with diabetes, the Diabetes Study of Northern California (DISTANCE). Diabetes Care 36:2697-2705

The objectives of this study were to test whether there was an association between food environments and obesity among adults with diabetes and whether this relationship differed according to individual income or race/ethnicity. We found that more healthful food environments were associated with lower obesity in the highest income groups among whites, Latinos, and Asians. The association was negative, but smaller and not statistically significant, among high-income blacks. In contrast, a more healthful food environment was associated with higher obesity among participants in the lowest-income group which was statistically significant for black participants in this income category. These findings suggest that the availability of healthful food environments may have different health implications when financial resources are severely constrained. Journal link.

in env justice, gis, health, our space

Tuesday

Oct162012

Sampling effects in PPGIS and VGI for public lands management

Tuesday, October 16, 2012 at 11:17AM

Brown, G., M. Kelly and D. Whital. 2013. Which “public”? Sampling effects in public participation GIS (PPGIS) and Volunteered Geographic Information (VGI) systems for public lands management. Journal of Environmental Planning and Environment 57(2): 190-214. doi: http://dx.doi.org/10.1080/09640568.2012.741045

Web 2.0 technologies including Public Participation Geographic Information Systems (PPGIS) and Volunteered Geographic Information (VGI) provide methods for engaging multiple publics in public lands management. We examined the effects of sampling in a PPGIS/VGI application for national forest planning in the U.S. A random sample (RS) of households and a volunteer public (VP) were invited to participate in an internet-based PPGIS to identify national forest values and use preferences. Spatial and non-spatial group responses were analysed. The VP group expressed stronger utilitarian values and consumptive use preferences while the RS group preferred forest amenities. These results would lead to different planning decisions. PPGIS/VGI methods should include scientific sampling to ground-truth voluntary participation. Journal Link.

Key words: public participation . PPGIS . volunteered geographic information . VGI . forest planning . public lands

in forests, gis, landowners, participatory, web

Page 1 2 3 4 ... 4 Next 10 Entries »

Spatial pattern of BMI among adults in Northern California

Laraia, B. A., S. D. Blanchard, A. J. Karter, J. C. Jones-Smith, M. Warton, E. Kersten, M. Jerrett, H. H. Moffet, N. Adler, D. Schillinger, and M. Kelly. 2014. Spatial pattern of Body Mass Index among adults in the Diabetes Study of Northern California (DISTANCE). International Journal of Health Geographics 13:48 doi:10.1186/1476-072X-13-48

clustering of high and low BMIThe role that environmental factors, such as neighborhood socioeconomics, food, and physical environment, play in the risk of obesity and chronic diseases is not well quantified. Understanding how spatial distribution of disease risk factors overlap with that of environmental (contextual) characteristics may inform health interventions and policies aimed at reducing the environment risk factors.

Click to read more ...

What is "marginal land"? a review of the ways GIS is used to model (and define) "marginal land" for biofuel production

Lewis, S. and M. Kelly. 2014. Mapping the potential for biofuel production on marginal lands: differences in definitions, data and models across scale. International Journal of Geo-Information 3(2), 430-459; doi:10.3390/ijgi3020430

As energy policies mandate increases in bioenergy production, new research supports growing bioenergy feedstocks on marginal lands. Subsequently there has been an increase in published work that uses Geographic Information Systems (GIS) to map the availability of marginal land as a proxy for bioenergy crop potential. However, despite the similarity in stated intent among these works a number of inconsistencies remain across studies that make comparisons and standardization difficult. We reviewed a collection of recent literature that mapped bioenergy potential on marginal lands at varying scales, and found that there is no common working definition of marginal land across all of these works. Specifically we found considerable differences in mapped results that are driven by dissimilarities in definitions, model framework, data inputs, scale and treatment of uncertainty.

Click to read more ...

Mapping potential for switchgrass as a biofuel in the US

One model outcome from the analysis.Lewis, S.M., G. Fitts, M. Kelly, L. Dale. 2014. A fuzzy logic-based spatial suitability model for drought-tolerant switchgrass in the United States. Computers and Electronics in Agriculture 103:39-47

Switchgrass (Panicum virgatum) has been targeted by the U.S. Department of Agriculture as an exemplary bioenergy crop, however it requires a significant amount of water and experiences reduced yields in water-stressed conditions. To avoid competition for prime agricultural areas, lands that receive adequate rainfall but are marginal due to highly variable timing of rain are potentially ideal locations to grow drought-tolerant biofuels. As scientists develop a modified variety of switchgrass that can withstand periods of drought while not substantially affecting overall yield, it is important to identify the potential geographical niche for this xerophytic crop to maximize its environmental and economic sustainability. This project uses a spatial suitability modeling approach that incorporates fuzzy logic and utilizes both physical and economic variables.

Click to read more ...

SLR and wetlands in the SF Bay

The resilience of four marshes examined in this paper.Schile, L.M., J.C. Callaway, J.T. Morris, D. Stralberg, V. T. Parker, and M. Kelly. 2014. Modeling tidal marsh distribution with sea-level rise: evaluating the role of vegetation and upland habitat in marsh resiliency. PLOS One 9(2): e88760

Tidal marshes maintain elevation relative to sea level through accumulation of mineral and organic matter, yet this dynamic accumulation feedback mechanism has not been modeled widely in the context of accelerated sea-level rise. Uncertainties exist about tidal marsh resiliency to accelerated sea-level rise, reduced sediment supply, reduced plant productivity under increased inundation, and limited upland habitat for marsh migration. We examined marsh resiliency under these uncertainties using the Marsh Equilibrium Model, a mechanistic, elevation-based soil cohort model, using a rich data set of plant productivity and physical properties from sites across the estuarine salinity gradient. Four tidal marshes were chosen along this gradient: two islands and two with adjacent uplands. Varying century sea-level rise (52, 100, 165, 180 cm) and suspended sediment concentrations (100%, 50%, and 25% of current concentrations), we simulated marsh accretion across vegetated elevations for 100 years, applying the results to high spatial resolution digital elevation models to quantify potential changes in marsh distributions.

Click to read more ...

in gis, modeling, open access, wetlands

Sunday

May052013

Income and ethnicity differences among people with diabetes

Sunday, May 5, 2013 at 8:12PM

Jones Smith, J. C., M. Wharton, M. Kelly, E. Kersten, A. Karter, N. Adler, D. Schillinger, H. Moffett, B. A. Laraia. 2013. Obesity and the food environment: income and ethnicity differences among people with diabetes, the Diabetes Study of Northern California (DISTANCE). Diabetes Care 36:2697-2705

The objectives of this study were to test whether there was an association between food environments and obesity among adults with diabetes and whether this relationship differed according to individual income or race/ethnicity. We found that more healthful food environments were associated with lower obesity in the highest income groups among whites, Latinos, and Asians. The association was negative, but smaller and not statistically significant, among high-income blacks. In contrast, a more healthful food environment was associated with higher obesity among participants in the lowest-income group which was statistically significant for black participants in this income category. These findings suggest that the availability of healthful food environments may have different health implications when financial resources are severely constrained. Journal link.

in env justice, gis, health, our space

Tuesday

Oct162012

Sampling effects in PPGIS and VGI for public lands management

Tuesday, October 16, 2012 at 11:17AM

Brown, G., M. Kelly and D. Whital. 2013. Which “public”? Sampling effects in public participation GIS (PPGIS) and Volunteered Geographic Information (VGI) systems for public lands management. Journal of Environmental Planning and Environment 57(2): 190-214. doi: http://dx.doi.org/10.1080/09640568.2012.741045

Web 2.0 technologies including Public Participation Geographic Information Systems (PPGIS) and Volunteered Geographic Information (VGI) provide methods for engaging multiple publics in public lands management. We examined the effects of sampling in a PPGIS/VGI application for national forest planning in the U.S. A random sample (RS) of households and a volunteer public (VP) were invited to participate in an internet-based PPGIS to identify national forest values and use preferences. Spatial and non-spatial group responses were analysed. The VP group expressed stronger utilitarian values and consumptive use preferences while the RS group preferred forest amenities. These results would lead to different planning decisions. PPGIS/VGI methods should include scientific sampling to ground-truth voluntary participation. Journal Link.

Key words: public participation . PPGIS . volunteered geographic information . VGI . forest planning . public lands

in forests, gis, landowners, participatory, web

Income and ethnicity differences among people with diabetes

Jones Smith, J. C., M. Wharton, M. Kelly, E. Kersten, A. Karter, N. Adler, D. Schillinger, H. Moffett, B. A. Laraia. 2013. Obesity and the food environment: income and ethnicity differences among people with diabetes, the Diabetes Study of Northern California (DISTANCE). Diabetes Care 36:2697-2705

The objectives of this study were to test whether there was an association between food environments and obesity among adults with diabetes and whether this relationship differed according to individual income or race/ethnicity. We found that more healthful food environments were associated with lower obesity in the highest income groups among whites, Latinos, and Asians. The association was negative, but smaller and not statistically significant, among high-income blacks. In contrast, a more healthful food environment was associated with higher obesity among participants in the lowest-income group which was statistically significant for black participants in this income category. These findings suggest that the availability of healthful food environments may have different health implications when financial resources are severely constrained. Journal link.

Sampling effects in PPGIS and VGI for public lands management

Brown, G., M. Kelly and D. Whital. 2013. Which “public”? Sampling effects in public participation GIS (PPGIS) and Volunteered Geographic Information (VGI) systems for public lands management. Journal of Environmental Planning and Environment 57(2): 190-214. doi: http://dx.doi.org/10.1080/09640568.2012.741045

Web 2.0 technologies including Public Participation Geographic Information Systems (PPGIS) and Volunteered Geographic Information (VGI) provide methods for engaging multiple publics in public lands management. We examined the effects of sampling in a PPGIS/VGI application for national forest planning in the U.S. A random sample (RS) of households and a volunteer public (VP) were invited to participate in an internet-based PPGIS to identify national forest values and use preferences. Spatial and non-spatial group responses were analysed. The VP group expressed stronger utilitarian values and consumptive use preferences while the RS group preferred forest amenities. These results would lead to different planning decisions. PPGIS/VGI methods should include scientific sampling to ground-truth voluntary participation. Journal Link.

Key words: public participation . PPGIS . volunteered geographic information . VGI . forest planning . public lands