Location mapping algorithm of regional data elements is
shown in Table. 2. In the real-world layer, there are many
streets surrounding a user, and each street also has many
coordinates. Let S be the set of streets and the detailed
coordinates of streets be Sk. In order to map the regional
data element, real_c, onto the street, an arbitrary street W
which belongs to S is selected. By calculating the distance
between real_c and arbitrary coordinates w on the chosen
street W, the detailed coordinates of the nearest street is
searched.