Halfmile PCT iPhone App Usage Notes:

Halfmile’s PCT app is a companion app to Halfmile’s Pacific Crest Trail printed map set to aid navigation on the PCT. The app uses the iPhone’s GPS to determine your location and calculates trail distances to 3,100 PCT landmarks along or near the PCT. Should a hiker stray off-trail, the app includes a live trail diagram to aid navigation back to the trail. The app works in areas without cell phone service. No extra downloads of data are required after the Halfmile PCT app is installed on your iPhone.

The Halfmile app is available as a free download from Apple’s iTunes app store.

The app has three modes of operation:

ByTrail Mode is like a location aware digital data book. The iPhone GPS calculated your exact location to the nearest 1/100th of a mile. The app also calculates the distance along the path of the PCT to landmarks to your north or south. ByTrail mode only works when you are actually on (or very near) the trail.

ByCrow Mode is used if you are not actually on the Pacific Crest Trail. In ByCrow mode the app displays the distance and compass bearing (as the crow flies) to PCT landmarks. ByCrow is also sometimes helpful for locating landmarks (such as water sources) that may be located a short distance off the trail.

Diagram Mode displays the Pacific Crest Trail and Halfmile landmarks as a diagram map along with your current location. Diagram mode is found under the “Where am ?” window.

Battery Conservation
Using the iPhone GPS will shorten the battery life of the iPhone. This is especially true when the iPhone is in fringe reception areas with weak cell phone signals where the iPhone cellular radio’s use the most power. Many hikers will keep their iPhone in Airplane Mode to conserve battery life and only disable Airplane Mode briefly when the GPS is needed to determine your location. The Airplane mode switch is found under Settings > Airplane Mode.

Unlike most Android phones, the iPhone disables the GPS (and all the other radios) when Airplane Mode is turned on. Without the iPhone GPS, many features of Halfmile’s PCT app will not work.

Your iPhone has four different radios — cellular, GPS, bluetooth, and wi-fi. Enabling Airplane Mode disables all four of the iPhone radios cellular, wi-fi and bluetooth radios (wi-fi and bluetooth can be re-enabled in settings when in airplane mode). It is possible in the iPhone settings to turn on bluetooth and wi-fi once Airplane Mode is enabled, but it is not possible turn on the GPS. the iPhone GPS now works in airplane mode beginning with iOS version 8.3 released in April of 2015.

An alternative to Airplane Mode is to use an iPhone SIM PIN. This prevents the iPhone cellular radio from working, and then other settings are used to turn off wi-fi and bluetooth so that only the GPS radio is enabled for maximum battery life of your phone.

Here’s how to enable the SIM PIN:

Select Settings > Phone > SIM PIN >

Turn off your phone

Turn on your phone. When “Sim Locked” is displayed select OK to continue using the phone with the SIM locked. Your phone will display “Locked SIM” in the top left corner of the screen and your phone radio will remain off. Note that you will not be able to receive cell phone calls when the SIM is locked. If you want to make a phone call, you will be prompted to unlock the SIM. Do this by selecting “Unlock” then enter the PIN (probably “1111” unless you changed it), then select OK.

Adventure Alan has published a very useful web page of iPhone information.