Does anyone have any idea how difficult it would be to create 5-digit zip code boundaries from scratch?
Let's suppose you start with a good outline of the US. Where would you source the fundamental zip code routes (I cannot find it on USPS.com)?
How much time and computing power are required to transform this data into reasonable polygons (I'm not looking for the most accurate)? Are open-source tools up to the job or are specialist tools required e.g. ArcGIS? Maybe you'd need to tackle it State by State? What sort of budget is required? Anyone got any insights?