5.5. Geolocation Data The geolocation table contains the latitude and the longitude values at lattice points and can be extracted from the HDF file. The latitude and the longitude values at other pixel position can be calculated by linear interpolation from the values at the lattice points. Latitude values are expressed as the geocentric coordinates. Note that the geolocation values (the latitude and the longitude values) are defined as being at the center of each pixel. The geocentric latitude Ψ can be easily converted into the geodetic latitude φ as follows. 　　tanφ=CtanΨ 　　C = 1.0067395 Figure 5-7 shows the lattice point structure. The lattice points are common to all Level-1B data. The upper left (0,0) corner is the starting position of the lattice point. Other lattice points are defined with the spacing (block size) shown in Figure 5-7. The last line, and the last column in the lattice point table are located outside the defined scene area. Figure 5-7 Lattice points of geolocation table