Summary
I hope that this chapter has demystified WebGIS a bit. Having a powerful tool watch our backs (PostGIS of course!) is a good starter to writing our very own web-based GIS applications.
We have managed to touch upon many different tools in this chapter; we have also written our own WMS server and REST API, and consumed both along with GeoServer services. This is quite a lot, even though our examples are simple and focused.
When outputting TopoJSON we have touched topo geometry; if this seemed a bit unfamiliar stay tuned - the next chapter is all about PostGIS topology.