## 2 A Multi-Source Real Data Model for Intercity Link Communication Propagation Computing
### Data Extraction of Land Cover Distribution Types of Intercity Links from MODIS  
#### 2.3.1 Land Cover Type Distribution on Intercity Links of East China  
The MODIS Land cover product MCD12Q1 provides a series of 13 sets of scientific data sets with 500 m of resolution global land cover projections, which were published in an annual span, including five different land cover classification schemes of IGBP/UMD/LAI/BGC/PFT, and a new three-layer classification standard based on the land cover classification system (LCCS) from the Food and Agriculture Organization, including a quality assurance (QA) layer, posterior probability of the LCCS three-layer standard, and binary land water cover. MCD12Q1 was secondary validation datum based on cross-validation of the training dataset generated from projections. MCD12Q1 was derived from observations from the Terra and Aqua data inputs and was generated using MODIS reflectance data supervised classifications. The primary land cover program identified 17 land cover categories as defined by the International Geosphere-Biosphere Program (IGBP), including 11 natural vegetation categories, 3 developed and planted land categories, and 3 non-vegetated land categories, as listed in Table 2.  
Figure 4: Duct height (m) calculated by WRF on 1 June and 1 December 2018. (**a**) Duct height (m) on 1 June 2018. (**b**) Duct height (m) on 1 December 2018. Figure 5: Duct Strength (M-units) calculated by WRF on 1 June and 1 December 2018. (**a**) Duct strength (M-units) on 1 June 2018. (**b**) Duct strength (M-units) on 1 December 2018. Figure 6: DEM of the selected area. Figure 7: Flow chart of the extracting line-distributed DEM data from polygon-distributed DEM data. In this paper, the vegetation distribution in the latitude and longitude range areas was converted into WGS84 projection by positive selection projection and expressed in Figure 8:  
We converted the original sinusoidal projection of the MCD12Q1 to WGS84 projections. The original data of MCD12Q1 was tile distribution, which was similar to that of DEM. After converting the projection of MCD12Q1, the original square tile became a diamond distribution. Then the required intercity land type data were extracted from the adjacent converted diamond tile data. The value of the land type of the latitude and longitude of the intercity link was uniformly interpolated according to the equidistant latitude and longitude interval. Finally, we traversed the data coordinates in the shorter dimension direction (longitude direction or latitude direction), found the point closest to the longitude and latitude slope of the link, and performed a one-dimensional intercity link land type on \begin{table}
\begin{tabular}{c c} \hline \hline
**Number** & **IGBP Land Cover Type** \\ \hline
1 & Evergreen needleleaf forest (ENF) \\
2 & Evergreen broadleaf forest (EBF) \\
3 & Deciduous needleleaf forest (DNF) \\
4 & Deciduous broadleaf forest (DBF) \\
5 & Mixed forest (MF) \\
6 & Closed shrublands (CSH) \\
7 & Open shrublands (OSH) \\
8 & Woody savannas (WSA) \\
9 & Savannas (SAV) \\
10 & Grasslands (GRA) \\
11 & Permanent wetlands (WET) \\
12 & Croplands (CRO) \\
13 & Urban and built-up (URB) \\
14 & Cropland/natural vegetation mosaic (CVM) \\
15 & Snow and ice (SNO) \\
16 & Barren or sparsely vegetated (BSV) \\
17 & Water bodies (WAT) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: IGBP Land Cover Type. Figure 8: MCD12Q1-LC1 distribution of the selected region. the standard of the IGBP arrangement. The land cover types classified in the IGBP of the links from the four surrounding cities to Wuxi, marked in Figure 8, are shown in Figure 9:  
2.3.2 Determination of Corresponding Dielectric Parameters in the Area Covered by the Intercity Link  
The classification of the IGBP features was relatively fine, and there have been many studies on the empirical model and test results of several kinds of vegetation dielectric permittivities.