A month after Seattle's Tableau Software launched a free online tool for creating and sharing dynamic data visualization charts, Google Labs has announced a free online tool for creating and sharing dynamic data visualization charts.

Like Tableau Public, Google's "Public Data Explorer" comes as the federal government is posting huge buckets of data online through its Data.gov transparency project, stoking demand for tools to analyze and present the information.

But there are a few big differences in what's being offered to end users.

Google's experiment is relatively closed and seems aimed at building partnerships with public agencies as much as providing free Web tools. At this point its tools can only be used to analyze a handful of datasets that Google's procured from public sources. Google's asking agencies to suggest additional data that it can upload and publish on its platform.

Tableau already has partnerships with agencies using its commercial visualization tools in-house. The free public version released last month is more open than Google's and can be used on any data. Users of the free version also have to share the underlying data via the visualization, while Google's tool doesn't yet allow the data to be downloaded directly.

Here's an example of a visualization created with Google's new tool:

Here's a Tableau Public visualization blending unemployment with venture capital and housing data: