4.4. Geometric Correction Data The geometric correction table contains the latitude and the longitude values at lattice points and can be extracted from the HDF file. The Lattice Point Tables are also in 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 except for the TIR bands. For TIR bands, in addition to the linear interpolation, a correction has to be applied to calculate the latitude and the longitude values precisely. See the TIR focal plane configuration in the User's Guide Part I for more details. The latitude values are expressed as the geocentric coordinates. Note that the geometric correction values (the latitude and longitude values) are defined as being at the center of each pixel. The Earth ellipsoid is limited to WGS-84. It should therefore be noted that the observation point expressed as latitude and longitude is the intersection of the WGS-84 ellipsoid and an extension of the line-of-sight vector. The terrain error is included in the latitude and longitude values caused by the difference between WGS-84 ellipsoid and the actual Earth's surface. The geocentric latitude Ψ can be easily converted into the geodetic latitude φ as follows. 　　tanφ=CtanΨ 　　C = 1.0067395 Figure 4-6 shows the lattice point structure. The first line, the last line, and the last column in the lattice point table are located outside the defined scene area to make interpolation possible for all pixels. Figure 4-6 Lattice point structure of geometric correction table