Month: December 2010

NRC Study: Precision Geodetic Infrastructure: National Requirements for a Shared Resources

/ Matt Artz

…from the Committee on the National Requirements for Precision Geodetic Infrastructure; Committee on Seismology and Geodynamics; National Research Council…

“Recognizing that the precise geodetic infrastructure is a shared national resource, and responding to the Decadal Survey’s warning that this infrastructure is degrading and at risk of collapse, NASA, NOAA, NSF, USGS, the U.S. Naval Observatory, and the National Geospatial-Intelligence Agency asked the National Research Council to establish a committee to assess the state of the U.S. geodetic infrastructure, to define the need for and role played by this infrastructure, and to make recommendations on how to maintain its viability in the future.

“Geodesy is the science of accurately measuring the Earth’s shape, orientation in space, and gravity field, and the changes in these properties over time. The precision of geodetic measurements has increased by several orders of magnitude over the past half century; in that time span, geodesy has proven immensely valuable for both scientific and commercial applications. Techniques and instrumentation developed for geodesy have enabled scientists to determine the changing position of any point on the Earth with centimeter accuracy or better. They also provide the technological underpinnings for accurately determining satellite orbits, measuring sea level rise, determining flood maps, monitoring coastal wetland changes, assessing groundwater resources, and monitoring earthquakes and other natural hazards. Even more precise and reliable geodetic measurements could enable an enormous array of advanced applications in autonomous navigation, precision agriculture, space exploration, hazard prediction, and other areas. Geodetic measurements are made using a variety of satellites, ground-based sensors and receivers, laser ranging devices, radio beacons, radio telescopes, and data-integration methods—a set of tools collectively known as the precise geodetic infrastructure.”

The Constraints and Benefits of Space and Time in Digital Social Networks

/ Matt Artz

Spatio-Temporal Constraints on Social Networks Workshop, University of California, Santa Barbara, Center for Spatial Studies, 13-14 December 2010

Matthew Zook

“I highlight three key issues related to integrating the constraints and benefits of space and time in digital social networks. They are (1) selecting the appropriate space-time scale of analysis; (2) integrating space and time within existing theories of strong/weak social ties; and (3) recognizing that software is an actor.”

Top Posts of 2010

/ Matt Artz

It’s that time of year when we take a look back to see how we did.  2010 was a year of growth for GISandScience.com–traffic more than doubled compared to 2009.  But more about that later.  First let’s take a look at the most heavily visited posts over the course of the year.

Top 15 Posts of 2010

  1. Accuracy of iPhone Locations: A Comparison of Assisted GPS, WiFi, and Cellular Positioning – 5,706 page views
  2. Jack Dangermond Talks About GeoDesign at TED 2010 – 2,478 page views
  3. Spatial Statistics, Geostatistics, and GIS: Free Training Available – 2,378 page views
  4. Top Five Benefits of GIS – 2,229 page views
  5. Geospatial Modelling Environment: A Platform Designed for Rigorous Spatial Analysis and Modelling – 983 page views
  6. Hot Spot Analysis – An ArcGIS Tutorial – 873 page views
  7. Call For Papers: IJAGR Special Issue on Spatial and Temporal Data Analysis – 832 page views
  8. Original ESRI Brochure from the Late 1970s – 813 page views
  9. What Would Happen if the Earth Stopped Spinning? – 798 page views
  10. “Data for Decision”, 42 Years Later – 720 page views
  11. James Baker of the Clinton Foundation in The Economist on the Use of GIS for REDD – 706 page views
  12. GIS/Geospatial Industry Worldwide Growth Slows to 1% in 2009 – 677 page views
  13. Spatial Statistics in ArcGIS: Free Sample Chapter from the Handbook of Applied Spatial Analysis – 540 page views
  14. New Spatial Analysis Tutorial Workbook Published – 522 page views
  15. The Evolution of the Epidemic of Charcoal-Burning Suicide in Taiwan: A Spatial and Temporal Analysis – 481 page views

Perhaps most surprising here is how many of these posts were created not in 2010, but in 2009.  I guess there’s nothing like the classics.  Now let’s take a look at the most heavily visited pages over the course of the year.

Top 15 Pages of 2010

  1. Home page – 52,220 page views
  2. Resources – 2,715 page views
  3. Books – 2,576 page views
  4. GeoDesign: A Bibliography – 2,282 page views
  5. About – 2,152 page views
  6. Agent-Based Modeling and GIS – 1,261 page views
  7. Integrating GIS with Models: A Bibliography – 1,212 page views
  8. GIS and Climate Change Resources – 912 page views
  9. Interviews – 858 page views
  10. Bibliographies – 784 page views
  11. GIS for Climate Change Bibliography, Part 1: Climate Science – 699 page views
  12. Spatial Statistics and Geostatistics Resources – 696 page views
  13. Using GIS for Air Quality Management and Air Pollution Assessment: A Bibliography 588 –  page views
  14. History – 475 page views
  15. GIS for Climate Change Bibliography, Part 5: Disaster Management – 423 page views

Summary Stats

2011 saw ~187,000 page views on GISandScience.com (as compared to ~77,000 page views in 2009). Page views for 2010 averaged 513 a day.

The busiest day for the blog was 05 November 2010, with 1,105 page views; the busiest month, November 2010 with  21,060 page views.

Happy New Year everyone!

The Esri Logo: An Evolution

/ Matt Artz / 1 Comment

As Esri rolls out a new company logo, I decided to take a look back at Esri/ESRI logos through the years.  If I’m missing anything, and you have a copy of it, let me know and I will update this post!

 

The old “four square” logo, from back in the day:

 

The “four square” logo often appeared with the spelled-out company name next to it; sometimes in color:

 

The “four square” logo was occasionally “abbreviated” to two squares; sometimes in color:

 

In the early 1990s, ESRI moved to the “globe” logo:

 

This variation of the “globe” logo was used on business cards and stationary:

 

The “interim” logo was used on the web site and some print pieces in 2009 and early 2010:

 

And finally, the “new” logo (2010):

More GIS & Esri history…

Using Multispectral Analysis in GIS to Model the Potential for Urban Agriculture in Philadelphia

/ Matt Artz / 2 Comments

American Geophysical Union, Fall Meeting 2010

Dmochowski, J. E.; Cooper, W. P.

“In the context of growing concerns about the international food system’s dependence on fossil fuels, soil degradation, climate change, and other diverse issues, a number of initiatives have arisen to develop and implement sustainable agricultural practices. Many seeking to reform the food system look to urban agriculture as a means to create localized, sustainable agricultural production, while simultaneously providing a locus for community building, encouraging better nutrition, and promoting the rebirth of depressed urban areas. The actual impact of such system, however, is not well understood, and many critics of urban agriculture regard its implementation as impractical and unrealistic. This project uses multispectral imagery from United States Department of Agriculture’s National Agricultural Imagery Program with a one-meter resolution to quantify the potential for increasing urban agriculture in an effort to create a sustainable food system in Philadelphia. Color infrared images are classified with a minimum distance algorithm in ArcGIS to generate baseline data on vegetative cover in Philadelphia. These data, in addition to mapping on the ground, form the basis of a model of land suitable for conversion to agriculture in Philadelphia, which will help address questions related to potential yields, workforce, and energy requirements. This research will help city planners, entrepreneurs, community leaders, and citizens understand how urban agriculture can contribute to creating a sustainable food system in a major North American city.”

(via Adena Schutzberg)

GIS-based Multi-criteria Evaluation to Land Suitability Modelling for Giant Prawn (Macrobrachium rosenbergii) Farming in Companigonj Upazila of Noakhali, Bangladesh

/ Matt Artz

Computers and Electronics in Agriculture, Volume 70, Issue 1, January 2010, Pages 172-186

M. Shahadat Hossainand Nani Gopal Das

“Site selection is a key factor in any aquaculture operation, affecting both success and sustainability as well as solving conflicts between different activities and making rational use of the land. The study was conducted to identify appropriate site for the farming of giant prawn, Macrobrachium rosenbergii, in Companigonj of Noakhali, Bangladesh using previous termGISnext term-based multi-criteria evaluation taking 20 base layers of water quality, soil characteristics and infrastructure facilities. ASTER image and thematic layers were analyzed using ENVI and ArcView capabilities to develop a series of previous GIS models and prioritize the most suitable areas for prawn farming. The model output clearly indicates the location and extent of prawn farming area in different suitability scales, i.e., most suitable 11,999 ha (52%), moderately suitable 10,219 ha (45%) and not suitable 781 ha (3%) which was consistent with field verification data. The compactness of vast flood-free derelict lands with suitable water and soil quality as well as infrastructure facilities would be an appropriate option for prawn farming to diversify the economic activities of local communities.”

Ancient Watercourses and Biogeography of the Sahara Explain the Peopling of the Desert

/ Matt Artz

Proceedings of the National Academy of Sciences, published ahead of print December 27, 2010

Nick A. Drake, Roger M. Blench, Simon J. Armitage, Charlie S. Bristow, and Kevin H. White

“Evidence increasingly suggests that sub-Saharan Africa is at the center of human evolution and understanding routes of dispersal “out of Africa” is thus becoming increasingly important. The Sahara Desert is considered by many to be an obstacle to these dispersals and a Nile corridor route has been proposed to cross it. Here we provide evidence that the Sahara was not an effective barrier and indicate how both animals and humans populated it during past humid phases. Analysis of the zoogeography of the Sahara shows that more animals crossed via this route than used the Nile corridor. Furthermore, many of these species are aquatic. This dispersal was possible because during the Holocene humid period the region contained a series of linked lakes, rivers, and inland deltas comprising a large interlinked waterway, channeling water and animals into and across the Sahara, thus facilitating these dispersals. This system was last active in the early Holocene when many species appear to have occupied the entire Sahara. However, species that require deep water did not reach northern regions because of weak hydrological connections. Human dispersals were influenced by this distribution; Nilo-Saharan speakers hunting aquatic fauna with barbed bone points occupied the southern Sahara, while people hunting Savannah fauna with the bow and arrow spread southward. The dating of lacustrine sediments show that the “green Sahara” also existed during the last interglacial (∼125 ka) and provided green corridors that could have formed dispersal routes at a likely time for the migration of modern humans out of Africa.”

Inferring Social Ties from Geographic Coincidences

/ Matt Artz

Proceedings of the National Academy of Sciences, 2010 107 (52) 22436-22441; published ahead of print December 8, 2010

David J. Crandall, Lars Backstrom, Dan Cosley, Siddharth Suri, Daniel Huttenlocher, and Jon Kleinberg

“We investigate the extent to which social ties between people can be inferred from co-occurrence in time and space: Given that two people have been in approximately the same geographic locale at approximately the same time, on multiple occasions, how likely are they to know each other? Furthermore, how does this likelihood depend on the spatial and temporal proximity of the co-occurrences? Such issues arise in data originating in both online and offline domains as well as settings that capture interfaces between online and offline behavior. Here we develop a framework for quantifying the answers to such questions, and we apply this framework to publicly available data from a social media site, finding that even a very small number of co-occurrences can result in a high empirical likelihood of a social tie. We then present probabilistic models showing how such large probabilities can arise from a natural model of proximity and co-occurrence in the presence of social ties. In addition to providing a method for establishing some of the first quantifiable estimates of these measures, our findings have potential privacy implications, particularly for the ways in which social structures can be inferred from public online records that capture individuals’ physical locations over time.”

Real-time Environment Representation Based on Occupancy Grid Temporal Analysis using a Dense Stereo-Vision System

/ Matt Artz

Proceedings of the 2010 IEEE 6th International Conference on Intelligent Computer Communication and Processing, Cluj-Napoca, Romania, 26-28 August 2010, pp.203-209

Andrei Vatavu, Sergiu Nedevschi, Florin Oniga

“We propose an environment representation technique by Temporal Analysis of the Occupancy Grid using a Dense Stereo-Vision System. The proposed method takes into account both the 3D information provided by the Occupancy Grid and the ego-car parameters. We use a method for computing the differences between the previous and current frames and compute an evidence space called Occupancy Grid Difference Map. Based on the difference map we created a reasoning component to generate an improved 2.5D model by representing the environment as a set of polylines with the associated static and dynamic features.”

Evolving Residential and Employment Locations and Patterns of Commuting under Hyper Growth: The Case of Guangzhou, China

/ Matt Artz / 1 Comment

Urban Studies, July 2010; vol. 47, 8: pp. 1643-1661., first published on February 8, 2010

Si-ming Li

“Chinese cities have experienced rapid growth and restructuring in recent times. This paper examines the evolving residential and employment locations and the changes in the patterns of commuting in Guangzhou, China. Tabulations derived from household surveys conducted in 2001 and 2005 show rapid suburbanisation of both residence and employment. Intrazone traffic today dominates the commuting scene in both the central core and the suburbs. The mean commute distance and mean commute time have increased, but the increases are quite modest. Estimation of residential and employment density gradients reveals differential decentralisation of different population groups. Multivariate analysis indicates that commute distance generally increases with income and occupational status. Males in Guangzhou used to have appreciably shorter commutes than females; but the difference has decreased in recent years, suggesting convergence in commuting behaviour between the Chinese and Western cases.”