Chapter 6. Spatial reference system considerations
This chapter covers
Up to this point we’ve been working mostly with fictitious data and only glimpsed at real-world data. Using sample data to learn the basics of PostGIS is an excellent beginning. You’re immediately rewarded with results without facing the distractions and the obstacles of real-world data. From this chapter forward, we’re not going to shield you any more.
We start this chapter with coverage of spatial reference systems. We follow up with exercises on determining the spatial reference of source data and selecting suitable ones for storage.
The art and science of modeling our bulbous earth and being able to get a 2D representation on paper have been around since the antiquities. Geodetics is the science of measuring and modeling the earth. Cartography is the science of representing the earth on flat maps. The intricacies of these two venerated sciences are far beyond the scope of this book. After all these mathematical gyrations, we end up with something that’s of utmost importance to GIS: the spatial reference system (SRS).