Map Viewing and Manipulation.

Under this viewing function, a user is provided with a capability to overlay map layers from different sources that can be accessed through the Internet. The user can also overlay map layers that are obtained from distributed sources over the Internet with the layers that reside in the local storage. This can further facilitate the user in his/her decision to assess the data before purchasing them. Once the user has decided to purchase the data, he/she can submit the order on-line and depending on the status of the user, he/she can proceed to download the data.