Extract Gantt Data from Visio Document Using C#

Hey I have a series of Gantt charts in Visio 2007 documents that I wa开发者_运维技巧nt to extract. I have looked at the visio sdk but that appears to be for creating new documents and plugins for visio itself. I know that you can export the chart as a text or MS Project MPX file but am looking for a way to just load the data from the visio document itself.

Thanks