do it need cellular data to use GPS app for walking?

[Naer]

Do I?

 

[Suspicious-Teach8788]

Technically to pinpoint your location via GPS, no.

However in order to speed up the GPS lock, you really need cellular data. It's hard to get a GPS only lock in a city with high rises. You need to stand on the roof, and even then it can take 30 seconds.

As for mapping, you need to make sure if you have offline maps. If you do have offline maps it may be theoretically possible to do fully offline navigation with GPS only. The issue is that the GPS antenna in general on phones isn't as strong as a standalone unit, say like a Garmin. As a result your lock times will be pretty horrendous on GPS only. IF you're in the suburbs it may work well, and I think the only challenges you may have could be on cloudy days. If you do intend on doing GPS only, I would recommend an app like GPS Status where you can download GPS location info for a week ahead. Use it to update GPS location info everytime you're on WiFi, so it can help boost your lock times. I found that it's a good help up to 2 days ahead, but the older the location data is, the slower your locks become.

 

[WelshBloke]

Setting my location settings to GPS only and disabling wifi and mobile data GPS test shows me getting a lock in a few seconds so I don't see why you should have a problem doing this.

 

[fuzzybabybunny]

A lot of phones have very weak GPS receivers.

I've been in places in the middle of nowhere with zero cell signal and GPS lock has taken forever. I would absolutely not depend on it for anything critical.

Likewise, I've flown into a different country and when I don't have data service GPS lock takes forever.

Both of the above cases occurred with Nexus and Samsung S4 with GLONASS and a wide open sky.

Disabling mobile data while you are in an area with cell signal is not a good simulation for "middle of nowhere conditions."

 

[gorcorps]

Depends on the app. I just downloaded one that stores map data locally and I've been able to navigate in airplane mode, so it works. But like said above, there's no telling what will happen in the boonies. I'm only going to use it if we get lost in Canada where I can't use my data anyway.

 

[NutBucket]

It's all relative folks. True cold start for any GPS receiver is on the order of 2 minutes or so.

 

[Suspicious-Teach8788]

Setting my location settings to GPS only and disabling wifi and mobile data GPS test shows me getting a lock in a few seconds so I don't see why you should have a problem doing this.

That's likely because you're coming off a hot lock. Try a cold lock and it will be tough. A good test is when I'm in a country where I don't want to pay for data (Japan is a PITA if you didn't order a SIM ahead of time), and its very difficult to use GPS there without data or first downloading GPS data over WiFi.