# A Method for Managing ADS-B Data Based on a 4D Airspace-Temporal Grid (GeoSOT-AS)
## 3 A 4D Airspace-Temporal Grid Framework (GeoSOT-AS) for ADS-B Data Organization
### GeoSOT-AS Rules and Methods for Planar Dimensional Profiling
#### 3.1.2 Planar Dimensional Coding Method  
**Definition 1**.: _Primary dissection blocks are those above the degree level of dissection, applicable to aeronautical plans at scales of 1:250,000 and above and corresponding to the first three levels of dissection in Table 1._  
**Definition 2**.: _Secondary sectioning blocks are the eight levels of sectioning below the degree level, for aerial plans at scales of 1:100,000 and below._  
The following coding methods from each of the two are described as follows, adapted to their method of dissection:  
(a) Coding method for primary profile blocks.  
The size of the first dissected grid cell is 6\({}^{\circ}\)\(\times\) 4\({}^{\circ}\). The Northern and Southern Hemisphere identification codes are \(N\) and \(S\), respectively; whereas the longitude direction is coded with 01-60, whereas the latitude direction is coded from the equator to the northern and southern hemispheres according to A-W. The coding direction is shown in Figure 2a. This profiling method corresponds to 1:1,000,000 charts, whereas the second profiling is in the form of 3\({}^{\circ}\)\(\times\) 2\({}^{\circ}\), and the space is coded as 1-4 according to the \(z\)-order (1:250,000 charts, as shown in Figure 2b). The degree level profile is in the form of 1\({}^{\circ}\)\(\times\) 1\({}^{\circ}\), corresponding to a 1:50,000 charts, and the above-degree level profile is regarded as the primary profile method of the airspace grid GeoSOT-AS.  
(b) Coding method for secondary profile blocks.  
There are seven levels of secondary blocks, corresponding to four types of profiles, 2 \(\times\) 2, 2 \(\times\) 3, 3 \(\times\) 2, and 5 \(\times\) 5 of the previous grid, coded in \(z\)-order as 1-4, 1-6, 1-6, and 01-25 respectively, with the finest profile granularity set to the second level. Here we need to emphasize that in the 6 th to 7 th and 10 th to 11 th levels of segmentation, there is a two-digit representation, whereas in the other levels, only one digit is required.  
The size of each level of the grid scale and its coding bit representation for the above GeoSOT-AS profiling method, as well as its corresponding coding method are shown in Figure 4.  
Figure 4: Four different types of fill curves: (**a**) 2 \(\times\) 3 profiling; (**b**) 2 \(\times\) 2 profiling; (**c**) 3 \(\times\) 2 profiling; (**d**) 5 \(\times\) 5 profiling.  
Figure 5 shows the coding bits and their representation from the 1 st to 11 th levels, where each digit is denoted by an asterisk *. Based on the above profiling and given coding methods, an example specified planar airspace area with a profiling range of [108\({}^{\circ}\)30\({}^{\prime}\)29\({}^{\prime\prime}\), 108\({}^{\circ}\)30\({}^{\prime}\)30\({}^{\prime\prime}\)], [23\({}^{\circ}\)35\({}^{\prime}\)25\({}^{\prime\prime}\), 23\({}^{\circ}\)35\({}^{\prime}\)26\({}^{\prime\prime}\)] can be progressively derived according to the completion of level-by-level profiling, and the principle of coding bit matching. In this example, the area code is N49F344140114206, where each digit or combination of digits corresponds to the dissection scale, and the prefix interception can be performed according to the requirements of different levels to determine the dimensional range of the previous level's plane.