City of Philadelphia Opens Data, Imagery to the Public

Esri logoFree APIs Encourage Citizens and Web Developers to Leverage Local Information

Through the OpenDataPhilly website, the City of Philadelphia, Pennsylvania, now provides access to over 100 datasets, applications, and APIs containing authoritative regional information on a wide variety of topics. The site includes a series of map services built with ArcGIS technology from Esri that offer data and imagery related to census tracts, political wards, crime incidents, hydrology, evacuation routes, bicycle networks, and more.

“Our goal is to expose current and accurate Philadelphia spatial data that will enable developers to build applications to benefit Philadelphia citizens and businesses, enhance commerce, and help streamline city government,” said James L. Querry, Jr., City of Philadelphia director of enterprise GIS. “The city has openly shared its core GIS data and imagery for over a decade, and now, in conjunction with OpenDataPhilly, we have recently expanded data and imagery access via APIs.”

Built by Philadelphia-based GIS software firm Azavea, OpenDataPhilly is based on the idea that providing free and easy access to information encourages more effective, transparent government and a more engaged and informed citizenry. ArcGIS technology from Esri supports the Gov 2.0 movement by enabling governments around the world to build mapping applications that empower the public and enhance policy making. To learn more about the role of GIS in open government, visit To access OpenDataPhilly, visit

[Source: Esri press release]

USDA and Esri Build Geospatial Portal Mapping Service

Esri logoPrivate GIS Cloud Opens Enterprise Opportunities

The US Department of Agriculture (USDA) and Esri have partnered in the implementation of a fully cloud-based geospatial portal. USDA’s prototype portal, Enterprise Spatial Mapping Service (ESMS), is built with Portal for ArcGIS, managed by Esri, and hosted on the Amazon cloud within USDA’s secure environment.

“ESMS empowers nontraditional GIS users, such as program analysts, economists, and research communities, to become confident working with maps and GIS analytic capabilities as part of their work,” said Stephen Lowe, chief geographic information officer for the USDA Enterprise Geospatial Management Office. “The GIS portal is cost-effective and provides rich resources. We anticipate that the service will extend, expand, and enhance department-wide use of spatial data and GIS competencies for a variety of tasks.”

USDA and Esri designed the prototype’s geospatial interfaces with a focus on search and discovery, hosting and publishing USDA-owned data, and the capability to display and analyze data. The private cloud GIS makes the central repository for authoritative content accessible to users within the department. ESMS provides a platform to

  • Quickly create maps and apps using templates and web mapping APIs.
  • Form groups to collaborate on projects or common activities.
  • Share maps and apps with private groups or the entire organization.
  • Embed maps and apps in custom web pages or blogs.

USDA and other external government agencies go through the portal to access valued agricultural datasets and maps from a browser and perform spatial analytics. Esri Managed Services maintains and supports the GIS and infrastructure for USDA. Users have the same collaboration and sharing tools as those provided in the public cloud mapping environment ArcGIS Online, but the site retains the USDA customization and brand. Esri’s Portal for ArcGIS is a geospatial content management system that can be hosted on-premises or as an off-premises cloud environment to provide a private, multitenant, geospatial content management system. USDA will eventually integrate its eAuthentication access control system with the private cloud solution to make the platform more secure.

In May, the prototype USDA portal was tested at the New Madrid National Level Exercise 2011, which is an event for developing regional catastrophic response and recovery activities. USDA representatives from the Animal and Plant Health Inspection Service (APHIS), Farm Service Agency (FSA), Natural Resources Conservation Service (NRCS), and other USDA agencies worked with the portal as a means to search for, discover, and share disaster response geospatial content. ESMS map products were used in presentations and briefings.

[Source: Esri press release]

Classifying the Hydrologic Function of Prairie Potholes with Remote Sensing and GIS

Wetlands, 2011, Volume 31, Number 2, Pages 319-327

Jennifer Rover, Chris K. Wright, Ned H. Euliss, David M. Mushet and Bruce K. Wylie

“A sequence of Landsat TM/ETM+ scenes capturing the substantial surface water variations exhibited by prairie pothole wetlands over a drought to deluge period were analyzed in an attempt to determine the general hydrologic function of individual wetlands (recharge, flow-through, and discharge). Multipixel objects (water bodies) were clustered according to their temporal changes in water extents. We found that wetlands receiving groundwater discharge responded differently over the time period than wetlands that did not. Also, wetlands located within topographically closed discharge basins could be distinguished from discharge basins with overland outlets. Field verification data showed that discharge wetlands with closed basins were most distinct and identifiable with reasonable accuracies (user’s accuracy = 97%, producer’s accuracy = 71%). The classification of other hydrologic function types had lower accuracies reducing the overall accuracy for the four hydrologic function classes to 51%. A simplified classification approach identifying only two hydrologic function classes was 82%. Although this technique has limited success for detecting small wetlands, Landsat-derived multipixel-object clustering can reliably differentiate wetlands receiving groundwater discharge and provides a new approach to quantify wetland dynamics in landscape scale investigations and models. ”

Visualising Space‐Time Dynamics: Graphs and Maps, Plots and Clocks

University College LondonThe International Symposium on Spatial‐Temporal Analysis & Data Mining at University College London, 18‐19 July 2011

Michael Batty, Martin Austwick, and Ollie O’Brien

“In many human systems, the size-distribution of the objects or events that define them reveals very few large objects and many small ones. Particularly in systems such as cities and firms, where to be large, you must once have been small, competition tends to make it increasingly unlikely that an object continually gets bigger with most objects never growing out of what has been called the ‘long tail’. These characteristics of scaling systems are often measured by power laws, the most popular of which is known as the rank size rule after Zipf. Populations of cities, revenues in firms, and incomes of individuals seem to follow such laws unerringly, with the form of the scaling remaining relatively stable from time period to time period. However when we examine how each individual object changes its size and rank at a micro level, there is considerable volatility with the half life of city sizes within the top 100 populations, for example, being something in the order of less than a century. To illustrate this volatility at the macro level in the face of strong stability at the macro, we have introduced the idea of the rank clock, where the rank of any city (or object) is plotted around the axes of a clock (where the 24 hour cycle is matched to the period over which the analysis takes place). Clocks for different system display remarkably different patterns and we thus suggest that a classification of different dynamics might be possible when we have enough comparable examples.

Rank Clocks of the Top 100 High Buildings

Rank Clocks of the Top 100 High Buildings in New York City (a) and the World (b) from 1909 until 2010

“In this talk, we will focus mainly on the visual analytics. The original analytics presents an animation of how systems change in terms of their rank and we begin by illustrating the general idea. As many of the spatial systems in which objects grow and decline in size and rank are spatial, we have linked the clock to related location maps of the objects and have ported the software to the web. This gives us much more power to examine individual cities in space and time but also lets us disseminate these ideas more effectively. We have also developed the rank clock as a kind of radar device where we have direct control over the speed and trajectories of the animation on the clock but we have also moved back to the idea of animating the rank-size space itself as well as more conventional animations of population change associated with sets of cities. One of the features of all these visualisation is that cities can be queried in the context of all others as they change in rank and size, thus providing a rich set of possibilities for the visual analysis of urban dynamics. In this talk we will illustrate these ideas using many examples: Cities in the US from 1790, recent metro areas in the US from the 1960s, skyscrapers in London, Japanese city populations, and UN data pertaining to GDP, literacy and such like.”