You can have access to terabytes of "public" data, but it may be next to useless. That was one of the lessons of the recent "Aid Challenge 2010" Data Camp at the World Bank Institute which explored ways to use data to make development aid more effective.
Doug Hadden , Vice President/Products at the financial management software company FreeBalance , explained :
"The major difference between open and public data is [that with open data] you have the ability to re-use it. Data in document format is effectively useless. By making [data] open...people can analyze, compare, and benchmark it, and find patterns that you did not realize."
The day-long event -- a mixture of BarCamp , ignite talk , and hackathon  -- brought together developers, data producers and visualizers, and practitioners and other members of the development community to give a big push to the gathering effort to bring more transparency to what governments do in their aid development programs.
Representatives of GeoCommons  showed how anyone who's got a batch of open data can, by following several steps  on the nonprofit's website, become a mapmaker producing striking visualizations that make quick sense out of a spreadsheet packed with columns and rows of dense textual information -- like the road system in Bandundu Province in the Democratic Republic of the Congo.
But if the data isn't "open," that is a barrier to the creation of maps that may make development aid more effective. As Kate Chapman , a software programmer with GeoCommons, said  at the Data Camp last Friday: "Open data is being able to take information and do whatever you want with it....Information flow is often a development challenge, whether it's giving people access to information on a micro level on the ground [or] on the macro level with big decision makers of who's giving aid where."