In chapter 3 of our book The GIS Guide to Public Domain Data, we discuss the increasing resolution, types, and ways to access sources of imagery and the implications of these changes for data users. Last week, imagery and for the continental United States and 60cm imagery for large parts of Western Europe arrived on the ArcGIS Online platform.
According to the announcement, http://blogs.esri.com/esri/arcgis/2012/12/20/digitalglobe-imagery-for-the-united-states-and-western-europe-added-to-the-world-imagery-map/, this is the first of several planned releases of new imagery from DigitalGlobe that will include Europe and many other parts of the world.
Another very useful feature is that with the Identify tool in ArcMap or the ArcGIS Online Content Viewer, or even inside the ArcGIS Online map viewer, the resolution, collection date, and source of the imagery can be obtained at the location on which you click. The metadata applies only to the best available imagery at that location. You may need to zoom in to view the best available imagery. The service was updated on the following servers: services.arcgisonline.com and server.arcgisonline.com. If you have previously used the World Imagery map, you may need to clear your cache in order to see the updates. For example, in the area in which I am examining in San Francisco, the popup indicates that the imagery is from 26 October 2010 and is at 30 cm resolution.
In our book The GIS Guide to Public Domain Data, we included several items from our colleague Matt Ball, who has been writing about spatial data for many years. His recent 10 geospatial predictions for 2013, http://www.sensysmag.com/dialog/perspectives/28845-ten-predictions-for-2013.html, touch on several key themes in our book, including growing scrutiny on location privacy, the growth of unmanned aerial vehicles and systems, cloud computing, government cuts, an increased ability to use place and location and associated tools in documentation and reporting, and government data “decrees.”
Which of these predictions do you think will come true? Which have already happened and simply will gain momentum? Which of these predictions do you believe have the most important implications for the field of GIS?
According to a recent US Government Accountability Office (GAO) report, despite numerous initiatives and administration goals, the lack of coordination between three major departments has led to significant amounts of duplicated geospatial data. One area of overlap specifically highlighted in the report is in the acquisition of road data, with all three agencies independently collecting the same information.
It transpires the departments, Commerce, Interior and Transportation, do not have an effective plan for advancing the sharing of geospatial data despite the specific remit of the Federal Geographic Data Committee to promote coordination among the three agencies. To date, the only goal all three department have achieved was making data available on a clearinghouse. Although the necessary policies for sharing data do exist, implementing those policies hasn’t been a priority as the agencies involved have been focussed on other activities.
Geospatial data silos and data duplication are not new; both have been around for almost as long as people have been collecting the data. Recent technological innovations – cloud computing, improved bandwidth, better data capture techniques, improved search engines and so on – were supposed to revolutionize our access to spatial data and make duplication like this a thing of the past. Instead they only serve to highlight how the major stumbling blocks to progress in sharing data continue to be organizational and administrative. Just how far up the collective ToDo list these data sharing initiatives will go in the wake of this report remains to be seen.
This week sees the publication of The GIS Guide to Public Domain Data. Available in both hard copy and as an e-book, the guide 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.
When co-author Joseph Kerski and I started this project, the open data revolution was well under way. Many individuals and organisations were advocating for improved access, preferably at no cost, to the vast reserves of spatial data collected by governments and organisations at local, regional, national, and international levels. At the same time, recent technological innovations, such as crowd sourcing and cloud computing, were also having a major impact on how people access, collect and work with spatial data.
Together these technical and organisational changes have had, and will continue to have, a significant influence on the availability of data in the public domain.