I want to automate the creation of boundary polygons from vector files. This is not footprint or extent creation (I already have scripts to do this). I want to create a tool similar to the QGIS, Image Boundary plugin which creates a single polygon which describes only the areas which have data. It should work on points/lines and polygons. For the points/lines, I guess it would need to create a buffer and then use that in generating a multipart boundary polygon (so it won't be exact but based on the buffer you set).
The purpose to use the output in a metadata catalogue where when you click on a location you only see a list of all files which have data in that spot and not just that the extent/footprint is within.
I found a tool from a post here that claims to do this but it is circa 2008 and isn't python based- http://blog.shoutis.org/2008/10/announcement-boundary-generator-v-01.html
An opensource QGIS/GDAL solution would be ideal but arcpy is fine as well.