The “official” way to store & transmit geographic coordinates. Less well-supported than ISO 8601.

ISO 6709 is the “official” way to textually represent geographic coordinates, as identified by the International Organization for Standards. It represents latitude, longitude, and altitude. Unlike its cousin standard ISO 8601, 6709 is not widely utilized by various programming languages.

It goes vertical coordinate (y), then horizontal coordinate (x), then altitude/depth. Positive numbers mean northern hemisphere, east of the Prime Meridian, and above sea level, respectively. Negative numbers are the opposite. Once altitude/depth are involved, things get complex. You need a reference point, of which there are a few registries (such as “WGS_84” (used by GPS, probably the most common)).

There are a few ways to do Lat/Long/Alt.

  • Using Degrees, Minutes, & Seconds:
    • 50°40′46.461″N 95°48′26.533″W
  • Using Degrees & decimal places:
    • +50.679573, -95.807370/
  • Including Altitude
    • +27.5916+086.5640+8850CRSWGS_84/

It appears as though the “CRSWGS_84” bit is implied in real-world applications I was able to find. For example - from the W3C wiki:

Mount Everest     +27.5916+086.5640+8850/
South Pole        -90+000+2800/
New York City     +40.75-074.00/ 

Source