Day: June 4, 2012

“The GIS Guide to Public Domain Data” Explains Sources and Quality of Spatial Data

/ Matt Artz

The GIS Guide to Public Domain Data The GIS Guide to Public Domain Data, published by Esri Press, provides GIS users with detailed information about the sources and quality of spatial data available in the public domain and the policies that govern its use.

This guide covers practical issues such as copyrights, cloud computing, online data portals, volunteered geographic information, and international data. It provides GIS practitioners and instructors with the essential skills to find, acquire, format, and analyze public domain spatial data. Supplementary exercises are available online to help put the concepts into practice.

“This book fills a very big gap in the literature of GIS and brings together for the first time discussions of issues users of public domain data are likely to confront,” says Michael F. Goodchild, professor of geography at the University of California, Santa Barbara (UCSB), and director of UCSB’s Center for Spatial Studies. “It will prove useful to GIS practitioners in any area of GIS application, including students anxious to learn the skills needed to become GIS practitioners and data producers who want their data to be as useful as possible.”

Written by Joseph J. Kerski and Jill Clark, the guide provides a critical evaluation of the various public domain data portals available and the merits of their data.

The GIS Guide to Public Domain Data (ISBN: 978-1-58948-244-9, 388 pages, US$49.95) is available at online retailers worldwide, at esri.com/esripress, or by calling 1-800-447-9778. Outside the United States, visit esri.com/esripressorders for complete ordering options, or visit esri.com/distributors to contact your local Esri distributor. Interested retailers can contact Esri Press book distributor Ingram Publisher Services.

[Source: Esri press release]

An Assessment of Vegetal-Cover Transition in Nigeria Using Temporal Analysis of Satellite-Derived Data

/ Matt Artz

Department of Environmental Management and Toxicology, University of Agriculture, Abeokuta, Nigeria
September, 2011

JOHN ADEBAYO OYEDEPO

“An assessment of vegetation dynamics in Nigeria from 1982 to 2009 was conducted using satellite spectral measurements of the earth. The study established current trends in vegetal-cover transition and its response to environmental changes. Monthly satellite-derived data for vegetation, land surface temperature and precipitation were acquired. Land measured data obtained from Nigerian Meteorological Agency were supplemented with field data. In this study, “Normalized Difference Vegetation Index” (NDVI) data sets from two satellite sensors; the National Oceanic and Atmospheric Administration’s Advanced Very High Resolution Radiometer (NOAA-AVHRR) and the National Aeronautics and Space Administration’s Moderate-Resolution Imaging Spectroradiometer (NASA-MODIS) were combined to characterize seasonal and inter-annual performances of vegetation through time. Harmonic Regression Analysis of Time Series (HARANTS), Empirical Orthogonal Tele-connections (EOT), Fourier Transform Analysis (FTA) and other algorithms were adopted for the assessment. Trends in seasonal and inter-annual variations in vegetal cover transition were examined. Transition in growing seasons and alterations in production efficiency of Nigerian vegetal-cover were equally investigated. The observed trends were correlated with variation in climatic and other environmental conditions in order to identify true change from mere environmental variations. From the results, a habitat index of 19.66 revealed that less than 20% of national land cover remains as natural vegetation as more than 56% of the total geographical area in Nigeria is human dominated. A decline in biomass and corresponding carbon fixation was recorded for the three decades examined. The percentage total tonnage of biomass accumulation and sequestered carbon for 1981-1990 was 54.4% while 1991–2009 accounted for the remaining 46%. Although there was a slight increase in the last decade but this trend clearly portends a precarious condition for terrestrial ecosystem. The Production Efficiency Model showed a general decline in monthly average Net Primary Production (NPP) with values ranging from 280 gm-2 in 1982 to 235gm-2 in 2009. The graph of mean NDVI values for the month of July in all the years indicated a rise from 0.33 in 1982 to a peak of 0.52 in 1994 and a decline to 0.39 in 2009. Phenology of the vegetal-cover revealed shifts in the commencement and termination dates of growing season from one decade to the other; a decline in length of growing season of 10 days was recorded in the south while as high as 80 days was recorded in the North. Positive correlation was observed between the satellite-derived metrics and actual land-measured ancillary data. Precipitation, surface temperature, soil moisture retention and solar radiation revealed high correlation coefficients (r > 0.6). The study demonstrated a general decline in the performance of Nigerian vegetal-cover and also supported utility of remotely sensed data as input to vegetation mapping indicating a very reliable source of real-time monitoring of environmental changes. The result of this study could be applied for early warning against natural disasters like drought and desertification.”

Update to Popular “My Place History” iPhone and iPad App Features Comprehensive EPA Data

/ Matt Artz
My Place History app

My Place History app

Esri today announced the release of My Place History 2.0, an updated version of the original unique iPhone and iPad application that provides personalized access to the Toxics Release Inventory (TRI) from the United States Environmental Protection Agency’s (EPA) database across the United States. The My Place History 2.0 application features the recent TRI data and allows users to review vital environmental information from around the country.

Users can also store in the application a permanent list of all places they have lived or worked, which in turn links these places to the TRI database. The link allows the application to create a shareable report that inventories the specific toxic releases reported within three miles of the users’ addresses.

“This application is useful in helping people understand the potential link between public health data stored in one database [toxic releases] and their individual places of residence or employment,” said Bill Davenhall, Esri’s global manager of health and human services. “There is a great deal of data collected to benefit public health. Unfortunately, this information seldom gets into the hands of the health-seeking consumers presenting symptoms to their physicians.”

In 2009, more than one-third (11,700) of residential ZIP Codes, 27 percent (5,300) of cities, and more than 50 percent (1,500) of all counties in the United States contained toxic releases recorded in the database released by EPA. No state escaped a toxic release reporting site in the 2009 TRI data. The TRI database contains the geographic location (latitude and longitude) of the more than 525 chemicals known to be hazardous to human health.

Most agricultural uses of chemicals and automobile emissions are not required to be reported. EPA’s toxic materials reported in My Place History are essentially those from manufacturing processes only. EPA has been collecting this type of data since 1983.

Applications like this are just the start of how society (patients and physicians) will benefit from the greater use of geographically relevant information and geographic information systems—a process Davenhall has coined geomedicine. Other data layers featured in the application are Dartmouth’s Health Atlas and regional Medicare heart attack rates.

Download the My Place History application from the Apple Store now.

[Source: Esri press release]