Understanding projected coordinate systems
The GCS tells you where data is located on the Earth’s surface. A PCS tells you how to draw and locate your data on a flat, two-dimensional plane. As mentioned previously, both the Earth and GCS models are spherical. However, most mapping mediums, be it a paper map or a mobile screen, are two-dimensional, flat surfaces. A PCS tells you how to convert the GCS spherical model to a flat model of the Earth’s surface.
It is often useful to develop a mental map by thinking about an orange. An orange is typically spherical and can be thought of as the Earth. As you peel an orange, you can lay its peel somewhat flat on a surface, but in order to get it completely flat, you must begin to tear the orange peel. Each tear in the orange peel can be thought of as distortion that is added to the model. A PCS, also known as a map projection, is essentially doing the same thing; it is tearing the GCS to allow it to be represented on our flat...
