Auto-populating mile marker values in a field

[MaitrayeeBasu]

Hi, 

I am a GIS intern and I am currently working on a project where field surveyors can quickly auto-populate the mile marker field attribute based on their location that is closest to the nearest mile marker. 

For example, if a surveyor is on the field and the closest mile marker is few miles away, instead of walking back to check the mile marker, it would generate itself along with how far they are from that mile marker. 

If anyone could help me out with this, I would greatly appreciate it!
Thankyou, 
Maitrayee

[DavidPike]

What application is this in? I'd say you really need to supply more details.

[MaitrayeeBasu]

Hi of course! 
They surveyors will be using ArcCollector and the layers will have to be updated on ArcOnline for them to access.