SRIDs
Each spatial instance or location has an SRID due to the earth being a non-standard ellipsoid. We talk about the surface of the earth, but what does this mean exactly? Do we plunge to the depths of the ocean floor or the highest mountains? The surface of the earth varies depending on where you are on the surface of the earth.
Spatial reference systems (SRS) allow you to compare different maps. If they are superimposable, they have the identical SRS. The European Petroleum Survey Group (EPSG) is the most popular.
Figure 1.1 visually demonstrates the discrepancy in mapping distances on the surface of the earth. Rotational forces at the poles flatten the earth, creating bulging at the equator. This phenomenon complicates the accurate calculation of the distance between two points located at different latitudes and longitudes on the Earth’s surface. The coordinate system helps to standardize spatial instances:
Figure 1.1 – Ellipsoid...
