Proximity alerts in a POI csv file?

Set POI Loader to "manual" instead of "express." It will allow you to set the distance you want.

That having been said, I'm not sure if you can set it as far as 52,800 feet (= 10 mi). The longest alert distance I use is 5,280 feet, and the one-mile warning seems to work just fine.

I'd test it, but my GPSr is in my car, and it's freezing in the garage.

As Spider_E said trying doing it in manual instead of express that usual works for me when i setup my proximity points

The technical limit for proximity alerts is 37 miles.

I've seen 37 miles quoted before, but:
37 miles is 59436 metres. Everything within Garmin's software seems to work in metres, so I would have expected that the limit is 65535 (2^16 -1) metres = 215009.8' == 40.72 miles.

Actually I couldn't resist trying this

Just wrote a gpx file containing

>gpxx:Proximity<65535.0>/gpxx:Proximity<


My StreetPilot reckoned it was happy with it (although the calculation's gone ever so slightly adrift): it said

Alert Information
Distance: 215007ft
Speed: none


(As expected, there's no sanity checking in POI-Loader. If you set the proximity to 75000 metres, you get a proximity of 31049ft instead i.e. there's an overflow somewhere )

IMHO - I would download the Combined Rest Area file as I believe you will get more consistent proximity alarms. The Combined Rest Area File has been modified to have Coordinates to the entrances to the rest areas. Secondly, setting the proximity alerts for 10 miles may cause you to have too many alerts.
May I suggest that when you are "looking ahead" that you just pull up the "Where to" > "My Locations" > "Custom POIs" > "Rest Area" (or whatever you name it) and it will give you listing of the closest 50 Rest Area/Service Plaza/Welcome Center/Turnout entrances.
You could also segregate out the Washington State only files from the Combined Rest Area File with POI Verifier if you only want Washington States.

Owww, that hurt my head. There's no math on Tuesdays!!! : )

Who knows?! I can't imagine wanting a 30 or 40 mile alert anyway.

I never said it was even faintly useful