Early on during the development of Flight Historian, I realized that I’d have to do some filtering of my maps by region. Most of my travel is within the United States, so a world map of all of my flights left the United States as an unreadable mess of lines. Thus, I gave Flight Historian the ability to toggle between world maps (all flights) and CONUS maps (flights within the CONtiguous United States – that is, the United States except for Alaska, Hawaii, and territories).
Because of peculiarities with how the Great Circle Mapper generates maps, showing region maps wasn’t as simple as setting a map center and zoom level. Instead, I had to know which airports were inside the CONUS and which ones were outside. The easiest solution was to add an
is_conus attribute to my Airports table, which would be set to true for CONUS airports and false for OCONUS (Outside CONUS) airports. Once I had that, I could set the world map to use every airport, and the CONUS map to show only airports where
is_conus was true.
This worked well enough when I was only showing two regions (world and CONUS). But as I traveled, I realized I was going to want to zoom in on other regions (for example, Europe) as well, which meant that I’d have to have some way match airports to other regions.