Hardest Part of Data Visualization

Much agree.  Simplicity of development, and then simplicity of understanding through interaction are key elements.  Tableau is good at this, but could also be better.    I suggest taking a look at some of their examples. Paul Lilford of Tableau talks about data source integration, a key issue: "  ... With visualization, there is an “ongoing challenge with the size of data and disparity of it,” according to Lilford. From a customer challenge perspective, “it’s really about getting to the size of data, all the sources of data, all the scale of things.” With Tableau being a data-driven company, the strategy is to combine all data sources quickly, helping customers make more data decisions at a detailed level. Social, web, third party, ERP — all these data sources have to lead to “something that’s consumable for business users.” ... "