This provides access to individual datasets data when you do not have the dataset id. Graphs with multiple datasets have an index, so the first dataset added is index 0, the next is index 1, ect..
ex: http://www.trendrr.com/api/feeds/graph_dataset?id=376964&dataset_index=0return=xml

authentication is optional (will allow you to view datasets that are not public).

params:

id (required)	this is the id of the graph
dataset_index	this is the index of the dataset. indexes start at 0 (default). If the graph has 2 datasets 0 would return the first dataset, 1 would return the second.
return	This value specifies what format you would like for the feed Possible Values: xml (Default) an xml feed json returns the feed in JSON format excel returns an excel file
start	index of datapoint to start with. a start of 0 would be the oldest datapoint in the dataset.
max	maximum number of datapoints to return.
sort_dir	What direction the datapoints are sorted. Timeseries datapoints are always sorted by date. Possible Values: asc (Default) points are returned oldest first desc points are returned newest first
start_date	You can specify a start and end date to return only the datapoints between those to dates. Should be in either XML encoding, or the number of seconds since epoch.
end_date	see start_date