Day: November 11, 2009

Structuring User-Generated Content

/ Matt Artz / 1 Comment

New Tools Enable Public Participation in GIS Database Development

For many years ESRI has promoted the idea of “GIS for everyone”, and more recently the pace of this movement has accelerated thanks to the Internet.  We tend to think of “GIS for everyone” as broad, practically universal access to data and GIS/mapping tools.   But another facet is public participation in that fundamental, essential component of GIS—building and maintaining the geospatial database.

Traditionally, geospatial database are “owned” by the creators of the geographic knowledge, which are typically the individuals or groups charged with building and maintaining the databases that support their organizational missions.  These databases are considered “authoritative,” meaning that they meet the standards of the organizational creators and are suitable to meet the needs of their intended applications.  But this database workflow has its critics.  “One of the criticisms leveled at GIS has been its insistence on a single point of view,” said Michael Goodchild, professor of geography at University of California, Santa Barbara.  To address such criticism, Goodchild says that we need a framework “in which individuals are able to assert their own views of their surroundings and play a part in local decision making.”

In the GIS realm, user-generated content (UGC) refers to geographic knowledge created by “end users” or the general public.  UGC is considered “assertive” geospatial data; while the provider of the data may be confident in its accuracy, this does not necessarily guarantee the data meets the information standards of the organization, or that it is suitable for the intended application.

Concerns about UGC are many.  In contrast to GIS-based data, which is organized with consistent data models and collected systematically, UGC is mostly observational, qualitative, and very rarely collected systematically in a science-based framework. It typically does not have an organized foundation, nor is it associated with metadata, and there is no responsibility with respect to the organization or individual who reported it.

So is there value in UGC in a GIS environment?   Yes.  There are many ways that GIS users can take advantage of the rapidly growing amount of UGC on the Web. They include:

  • Using the data to validate data analysis and compilation efforts
  • Using geotagged photos to enrich the multimedia dimension of a GIS
  • Associating the observational data to other layers for query and enrichment of the GIS
  • Integrating citizen/consumer comments with public policy systems
  • Finding suggestions and recommendations about particular places
  • Enhancing the systematic inventories of things like place names and other observational data

This method of collecting observational geographic data and engaging the public is very powerful, especially for community involvement in collaboration and communicating about situational awareness. “I think the most significant new opportunity lies in the fact that a substantial fraction of the human population now has access to mobile phones and, hence, to electronic networks,” said Goodchild.  “Mobile phones could be used to acquire and share damage assessments in the immediate aftermath of a disaster and to develop detailed databases for community planning.”

Structure is Key

The key to useful, actionable UGC is collecting the data in a structured manner.  The USGS-Caltech ‘Recent Earthquakes’ application (http://quake.wr.usgs.gov/recenteqs/) is as an interesting example of how to do this right.  ‘Recent Earthquakes’ lets people report their earthquake experiences over the web, but it doesn’t ask them to rate the intensity of the earthquake directly.  Instead, it walks people through a more objective, structured series of questions to help determine how strongly they felt the earthquake.  “On the back end, the application determines how ‘intense’ the experience was as an aggregate of responses to individual questions,” said Matt Artz, ESRI’s GIS and science marketing manager.  “The web-based map is an interesting and useful service in itself, but potentially even more useful is that the answers to the individual questions also form a very useful data set for further analysis.”

ESRI has been building functionality, such as the new ‘featurelayer’ capabilities in ArcGIS 9.4, to support such structuring of UGC, and Web API’s for capturing UGC are being developed.   Structured user-generated content becomes another geographic layer in the geodatabase.  Advanced applications such as analysis, modeling, forecasting, management, and planning are enabled by structured data.  ESRI will continue to develop enabling technology that builds these concepts into ArcGIS and make it an integral part of the GIS system architecture.

“User created data that’s validated through essentially a cloud framework is going to take over,” said Larry Orman, executive director of Green Info Network.  “You can’t fight with that.  Individuals are really going to play a major role in the way we (create) information.”

 

The Power of the People

“There are already signs that the traditional authorities are willing to work with citizens,” said Goodchild.  “In the UK [United Kingdom], for example, the Ordnance Survey has developed a program that encourages volunteers to provide geographic information about their local communities, and volunteers are playing an increasingly important role in ensuring that authoritative sources of geographic information are accurate and kept up-to-date.”

“Our military has a slogan: ‘Every soldier is a sensor,” said ESRI president Jack Dangermond.  “With UGC, every citizen is a sensor.  This is another chapter in democracy, opening up and letting citizens participate in the development of geographic databases,” said Dangermond.

Rainfall Redistribution in a Tropical Forest: Spatial and Temporal Patterns

/ Matt Artz / 1 Comment

…from the Water Resources Research journal…

Alexander Zimmermann, Institute of Geoecology, University of Potsdam, Potsdam, Germany

Beate Zimmermann, Smithsonian Tropical Research Institute, Balboa, Ancón, Panama

Helmut Elsenbeer, Institute of Geoecology, University of Potsdam, Potsdam, Germany; Smithsonian Tropical Research Institute, Balboa, Ancón, Panama

“The investigation of throughfall patterns has received considerable interest over the last decades. And yet, the geographical bias of pertinent previous studies and their methodologies and approaches to data analysis cast a doubt on the general validity of claims regarding spatial and temporal patterns of throughfall. We employed 220 collectors in a 1-ha plot of semideciduous tropical rain forest in Panama and sampled throughfall during a period of 14 months. Our analysis of spatial patterns is based on 60 data sets, whereas the temporal analysis comprises 91 events. Both data sets show skewed frequency distributions. When skewness arises from large outliers, the classical, nonrobust variogram estimator overestimates the sill variance and, in some cases, even induces spurious autocorrelation structures. In these situations, robust variogram estimation techniques offer a solution. Throughfall in our plot typically displayed no or only weak spatial autocorrelations. In contrast, temporal correlations were strong, that is, wet and dry locations persisted over consecutive wet seasons. Interestingly, seasonality and hence deciduousness had no influence on spatial and temporal patterns. We argue that if throughfall patterns are to have any explanatory power with respect to patterns of near-surface processes, data analytical artifacts must be ruled out lest spurious correlation be confounded with causality; furthermore, temporal stability over the domain of interest is essential.”

Map of the Day: Arizona’s Natural Infrastructure

/ Matt Artz / 1 Comment

…from the ESRI Map Book, Volume 24…

conservation1_sm“Arizona’s natural infrastructure includes lands and waters that preserve the state’s natural heritage and open space. The Nature Conservancy developed a natural infrastructure dataset by integrating twelve regional studies on wildlife habitat and open space and used the dataset to understand the potential impacts of Arizona’s future growth by 2050.

“Results show that although Arizona’s population is projected to double by 2050, its associated urban footprint may quadruple. If growth follows current projections, Arizona could lose nearly two million acres of natural infrastructure by 2050. This loss of desert, grassland, and forest habitat could jeopardize at least 120 species.

“However, there are 2.7 million acres of undeveloped private and state lands outside of the natural infrastructure and within 30 miles of existing highways. Shifting projected development into these areas would minimize direct impacts to the natural infrastructure.

“Courtesy of The Nature Conservancy.”