Groundwater Rights in Mexican Agriculture: Spatial Distribution and Demographic Determinants

The Professional Geographer, Volume 62, Issue 1 February 2010 , pages 1 – 15

Christopher A. Scott;  Sandy Dall’erba; Rolando Diacuteaz Caravantes

“Groundwater use intensity and aquifer depletion increase from south to north with decreasing rainfall and increasing economic activity in Mexico. To heighten scholarly understanding and offer new insights that strengthen policy responses to aquifer depletion, we analyze the spatial distribution of agricultural groundwater use from irrigation well titles in 2,429 municipalities and its relation to agricultural surface water and population employed in agriculture. Exploratory spatial data analysis reveals spatial dependence among all three variables implying that policy initiatives to address intensive groundwater use must be targeted at clusters of aquifers and municipalities.”

Darkness on the Edge of Town: Mapping Urban and Peri-Urban Australia Using Nighttime Satellite Imagery

The Professional Geographer, Volume 62, Issue 1 February 2010 , pages 119 – 133

Paul C. Sutton; Andrew R. Goetz; Stephen Fildes; Clive Forster; Tilottama Ghosh

“This article explores the use of nighttime satellite imagery for mapping urban and peri-urban areas of Australia. A population-weighted measure of urban sprawl is used to characterize relative levels of sprawl for Australia’s urban areas. In addition, the expansive areas of low light surrounding most major metropolitan areas are used to map the urban-bush interface of exurban land use. Our findings suggest that 82 percent of the Australian population lives in urban areas, 15 percent live in peri-urban or exurban areas, and 3 percent live in rural areas. This represents a significantly more concentrated human settlement pattern than presently exists in the United States.”

Comparison of Interpolation Methods for Depth to Groundwater and its Temporal and Spatial Variations in the Minqin Oasis of Northwest China

Environmental Modelling & Software, Volume 24, Issue 10, October 2009, Pages 1163-1170

Yue Sun, Shaozhong Kang, Fusheng Li, and Lu Zhang

“Severe water shortages and dramatic declines in groundwater levels have resulted in environmental deterioration in the Minqin oasis, an arid region of northwest China. Understanding temporal and spatial variations in the depth to groundwater in the region is important for developing management strategies. Depth to groundwater records for 48 observation wells in the Minqin oasis were available for 22 years from 1981 to 2003, allowing us to compare three different interpolation methods based on three selected years (1981, 1990, 2002) as starting points. The three methods were inverse distance weighting (IDW), radial basis function (RBF), and kriging (including ordinary kriging (OK), simple kriging (SK), and universal kriging (UK)). Cross-validation was applied to evaluate the accuracy of the various methods, and two indices – the correlation coefficient (R2) and the root mean squared error (RMSE) – were used to compare the interpolation methods. Another two indices – deviation of estimation errors (σ) and 95% prediction interval (95 PPI) – were used to assess prediction errors. Comparison of interpolated values with observed values indicates that simple kriging is the optimal method for interpolating depth to groundwater in this region: it had the lowest standard deviation of estimation errors and smallest 95% prediction interval (95 PPI). By using the simple kriging method and an autoregressive model for depth to groundwater based on the data from 1981 to 2003, this work revealed systematic temporal and spatial variations in the depth to groundwater in the Minqin oasis. The water table has declined rapidly over the past 22 years, with the average depth to groundwater increasing from 4.95 m in 1981 to 14.07 m in 2002. We attribute the decline in the water table to excessive extraction and to decreases in irrigation channel leakage.”

Mapping Change in Large Networks

Rosvall M, Bergstrom CT

PLoS ONE 5(1): e8694. doi:10.1371/journal.pone.0008694, January 27, 2010

“Change is a fundamental ingredient of interaction patterns in biology, technology, the economy, and science itself: Interactions within and between organisms change; transportation patterns by air, land, and sea all change; the global financial flow changes; and the frontiers of scientific research change. Networks and clustering methods have become important tools to comprehend instances of these large-scale structures, but without methods to distinguish between real trends and noisy data, these approaches are not useful for studying how networks change. Only if we can assign significance to the partitioning of single networks can we distinguish meaningful structural changes from random fluctuations. Here we show that bootstrap resampling accompanied by significance clustering provides a solution to this problem. To connect changing structures with the changing function of networks, we highlight and summarize the significant structural changes with alluvial diagrams and realize de Solla Price’s vision of mapping change in science: studying the citation pattern between about 7000 scientific journals over the past decade, we find that neuroscience has transformed from an interdisciplinary specialty to a mature and stand-alone discipline.”

Geospatial Dimensions of Emergency Response Symposium, 25-29 April 2010, Phoenix, Arizona

“The Geospatial Information & Technology Association (GITA) has created this unique forum to address the application of mapping technologies such as GIS, GPS, and remote sensing to emergency and disaster response. In response to a perceived need, GITA held the first ever Geospatial Dimensions of Emergency Response Symposium in Seattle, Washington in March 2008. The response was overwhelmingly positive in 2008 and in Tampa in 2009. In 2010 the symposium will once again bring together the worlds of emergency response and planning and geospatial technology April 25-29 in Phoenix, Arizona.”