If you want to analyze where your Twitter followers are located, do try out TweepsMap. TweepsMap analyzes your followers (after you authorized it to access the information) and maps them out on a world map.
This is effective if your followers provided their location on Twitter. If not, they will be ignored. In the above picture, you can see them TweepsMap. Almost 40% of my followers are from US and about 24% are from Singapore.
That means I have to spend more effort to interact with fellow Singaporeans or people residing in Singapore. This is a good way to measure the effectiveness of your social media presence.