Been using Mapmyride for over a year with a HRM. I don't think it uses data unless your dumping to the website which can be done via wifi later one. I turn off WIFI when using it and only keep the bluetooth running. I turn the screen brightness down and can get about 2.5 to 3 hours of use. I take along an extra battery in case.

Any app that contacts GPS is using data. It might not be much especially if you have your screen display turned off.
Turning of WIFI saves your battery because it is not looking for a signal.

Pretty much completely not true.

If you shut off the cellular connection (ie. data) and you run your map program, it will still record your position but you won't have a map to display the track against. There is no requirement that you need to have data to use GPS. It is true that the phones use a database of wifi network's geographical locations to speed a GPS fix, but it is not a necessary requirement to have any data to have GPS work. There are also mapping applications that store maps internally to the phone where you can use them to navigate even where there is no data network available. Garmin has a number of these and I have used them successfully in just that manner.

FWIW, you can also store a google map on your phone in the google maps application to be used without network access (airplane mode). According to the link, the map will reside on your phone for 30 days.

I have also ridden my bike using Cyclemeter in areas devoid of cellular coverage. The app faithfully stores my track and data and displays it on a grid. There is, of course, no base map behind it, but it's easy to see where I've been and if a route has been loaded, where I'm going.



J.

I like my cycle computer small and simple. I have a Garmin edge 500 that records everything I need. Only niggle is it takes some time triangulate GPS.

I could use my smart phone and tracks (I used to), but that is a PITA, doesn't capture everything I would like it to, and is too big for me to mount and monitor while I am riding.

Yeah not true. I use my iPad with a onboard maps application when 100's of miles off the grid while 4x4'in in the mountains. No cellular data, just GPS signal to pin point my location on the map.

The GPS receiver is built into the cellular data chipset. For example if you buy an iPad without 3G/4G you will get no GPS signal either.

I didn't realize that is possible.
But if you are using an app with GPS and not a downloaded map, you are using data. Right?

Like said, getting GPS (coordinate info) alone doesn't require cell data plan. When it's time to plot those coordinates on a map, you need the map data. You will have to download the map data either as you go (cell data plan or wifi connection) or do it beforehand (again cell data plan, wifi or transferring the map data from a laptop).

sold my garmin Edge 500, now using cyclemeter. No real increase in my data usage, battery not a issue (yet)

GPS is a signal from GPS satellites. It has nothing to do with phones/cell-network/data.

The maps really don't have anything to do with GPS. GPS only provides your location. (Maps are an add-on to the GPS.)

Programs/Apps use that information (your GPS location) and display it on a map.

Either the map data is stored on the phone's memory or it has to be downloaded as-needed across a network. If it has to be downloaded, this has to use the cell-network OR wifi (but you won't have wifi "on the road").

Phones are usually manufactured so that the same chip that provides access to the cell-network also receives GPS signals.

Some tablets provide a GPS receiver (one way data) whether or not they also provide a cell-network transceiver (two way data).

On the iPad, the GPS receiver and the cell-network transceiver are on the same chip (as is typical for phones).

You can use the GPS receiver without using the cell-network transceiver.

Devices with both a GPS receiver and a cell-network transceiver can do something called "assisted GPS" (aGPS), which uses locations of cell-towers (and wifi) to get a quick approximate fix of your location (but this doesn't use data). aGPS can (often) determine your location without having a GPS signal (like indoors). aGPS can also download a small amount of information (almanacs) that make GPS aquisition faster (this uses data).

GPS is the most accurate way to determine location but it needs clear-view of the sky and it can take a while to get an initial fix (once it has a fix, it's very fast).