5.4. Geometric Parameters Parameters related to geometric properties are map projection, ellipsoid, pixel size and resampling method. Major features of these parameters are as follows. Map Projection Map projections are limited to Universal Transverse Mercator (UTM), Lambert Conformal Conic (LCC), Polar Stereographic (PS), Space Oblique Mercator (SOM) and uniform Lat/Long. Map direction is limited to Path Oriented. For UTM, two standard longitude line method is adopted with a reduction rate of 0.9996 to define the cylinder. For LCC, two standard latitude lines of 53 and 67 degrees are adopted to define the cone position and angle. For PS, a standard latitude line of 70 degrees is adopted to define the plane position. FOR SOM, the nominal orbit path line is used as the position for contacting to the projected plane. Default map projection is UTM, regardless of latitude. Ellipsoid The Earth ellipsoid is limited to WGS-84. Therefore, it should be noted that the observation point expressed as latitude and longitude is the intersection of 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 a difference between the WGS-84 ellipsoid and the actual Earth's surface as shown in Figure 5-6 Figure 5-6 Terrain error Pixel Size It is the basic policy that the map-projected pixel size should not depend on data acquisition conditions such as instrument cross-track pointing and orbit drift but depends only on the Earth's surface position (latitude/longitude) for each map projection. The nominal pixel sizes are 15 m, 30 m and 90 m for VNIR, SWIR and TIR, respectively. Map-projected pixel sizes meet the nominal sizes along the standard lines. Resampling Method The nearest neighbor (NN), bi-linear (BL) and cubic convolution (CC) methods are available types of resampling. Default resampling method is cubic convolution