CONFORMALITY

projection of the polar region is the fact that in the conic projection, the cone is cut and flattened out to form the map or chart, whereas the gnomonic projection will appear as is. On the conic projection, points lying close together on either side of the meridian along which the cone is cut will be widely separated on the map. The gnomonic projection, on the other hand, will give a continuous and contiguous view of the areas. Figure 9-23 shows the appearance of meridians and parallels on a polar gnomonic pro- jection. CONFORMALITY According to some authorities, to be conformal, a projection must possess both of the following characteristics: 1. It must be a projection on which direction is the same in all parts of the map. Obviously, for this directional conformality, the meridians (which indicate the direction of true north) must be parallel, and the parallels (which indicate true east-west direction) must be parallel to each other and perpendicular to the meridians. 2. It must be a projection on which the distance scale north and south is the same as the distance scale east and west. Obviously, none of the projections that we have described have both of these characteristics. The only one that has the first characteristic is the Mercator. On this projection the meridians are parallel, and the parallels are parallel to each other and perpendicular to the meridians; therefore, the direction of north or east is the same anywhere on the map. With regard to the second characteristic, however, a distance of 15 degrees (for example) is longer in any part of the map north-south than a distance of 15 degrees east-west (even in the same part). Figure 9-23.-Meridians and parallels on a polar gnomonic projection. 9-20