How to automatically measure angles between lines ?

How to automate measuring angles between lines ? for example in the following image, is there a way to input the image and get the angles of all with respect to 1

https://picasaweb.google.com/116243239493929305987/March232012#5723091768420514962

Thanks Shanoob

[Jan]

Remark: What a pitty that this way to post images is such unconvenient. The question could be answered more directly, if the imga eis hosted on a TMW server and it appears embedded in the text. This feature has been discussed repeatedly and is included in Walter's (our!) wish-list already. But I feel a Friday evening frustration.

[Jan]

What does "automate" mean in your case? What kind of user interactions are wanted? And if no interaction are wanted, what kind of output do you need? An average angle between all pairs of lines, or a list of angles between pairs? Do you need to identify the lines individually?