Two days ago, I posted my Flare visualizations—based on a Flash/Actionscript library–explaining that we can’t yet use the D3 visualization library because it outputs SVG, which isn’t supported by older versions of IE.
The very next day, Hjalmar Gislasun of DataMarket gave a talk at O’Reilly’s Strata Conference. DataMarket faced the same problem back in 2010 after reviewing over 100 visualization libraries and choosing Protovis (a predecessor of D3). Not wanting to exclude the 20% of the world still using IE 7/8, they developed protovis-msie, a tool to convert Protovis SVG output to VML, a vector format understood by older browsers.
And…they open sourced it. So Protovis is now on the table for use at National Priorities Project. Thank you, DataMarket!
Like Flare, Protovis is no longer under active development. That said, it still has an active user community (unlike Flare). And the output won’t be Flash, so iOS is back on the table.
DataMarket’s strategy is to continue using Protovis until most IE users are on version 9 (which supports SVG) and then switch over to D3. It was refreshing to hear browser support strategies from people developing visualizations for commercial use; they don’t have the luxury of ignoring IE 8, which is tempting to do but not viable in the real world.