With RS5 being a complete rewrite of RS4, many little interesting tidbits are added where you do not expect them.
I found one of these in the /area command, and it proves to be quite handy in locating where you are;
When you're out in the ocean.
In RS4 when you were from the mainland into the endless ocean(ex. Mordor bridge) your area would've shown up as:
Location of Leon_Arallian: Mordor HighwayHowever, in RS5; Regions were introduced, and therefore make it easier to find you when you're lost in the ocean.
Refer to this map:

As this map shows; The regions are defined as such. This makes it easier to calculate where you are in the ocean;
Suppose that you drive too hard on the bridge to Mordor and fall off, and need someone to rescue you while you went swimming onward.
Your location upon using /area would be reported as this:
Location of Leon_Arallian: Region 2 5This is fairly easy to convert:
Location of Leon_Arallian: Region X=2 Y=5If you take the map in mind, You can easily see where you are.
Region 2 on the X axis shows you're near the vicinity of Mordor's bridge,
Region 5 on the Y axis shows you're quite far away from the mainland.
Did you know Mordor's island is in region 2 8?Once the pilot knows the estimated location it can search in the area for your presence, this can eventually be picked up by your blip on the minimap.
There's nothing more to say, this is how an unexplained feature got its explanation.