One of the major challenges of using spatial information is transferring points from a spherical object, like the earth, and displaying them on a two dimensional map. The sciences of geodesy and surveying are used by cartographers to accomplish this task. Unfortunately there is not just one way to project points to a flat map. Each transfer of points, called a projection, has a specific purpose. A projection will preserve some information (i.e. shape) but distort others (i.e. area). Although there is not a ‘best projection’, the one most commonly used in the Philippines, is the transverse mercator [TM]. A TM is used because the country stretches primarily in a north-south direction. Projections are just one part of a spatial reference framework. The framework is further defined by an ellipsoid, geoid, datum and coordinate system. Read More
