Many iOS devices have a built in GPS receiver, and will work very well with iHikeGPS even if you do not have a cellular data plan. The confusion comes about because the GPS receiver and the cellular radios are both included in the same package. If one buys an iOS device without the cellular radios, then he doesn't get the GPS receiver either. But the GPS receiver and the cellular radios can work independently. When the GPS receiver is first turned on by an App requesting to use it, if you have a cellular plan and a network connection, the GPS receiver will use information that it gets over the network connection to more quickly lock onto the GPS satellites. But if there is no cellular plan, the GPS receiver will get that necessary information directly from the GPS satellites, which can take a minute or two (just a like a separate GPS unit would). Once the GPS receiver is locked onto the satellites, it does not use the cellular plan at all, and its performance is identical whether you have a cellular plan or not.

Yes, iHikeGPS is a native iPad App, with full support for the Retina display in the newer iPads. Apple installs a GPS chip in the WiFi+Cellular versions of the iPad. Thus, all features of iHikeGPS work with these iPads. The WiFi-only versions do NOT have a GPS chip, but map download and viewing is still supported by iHikeGPS. To access all functions of our software with a WiFi-only iPad, add an iOS-compatible external GPS receiver.

Yes, iHikeGPS works on the iPod touch. The iPod touch does NOT have a GPS chip, but map download and viewing is still supported by iHikeGPS. To access all functions of our software with an iPod touch, add an iOS-compatible external GPS receiver.

Yes. There are some iOS-compatible external GPS receivers available. These can offer improved GPS performance over the built-in GPS chip, or full functioning for those Wi-Fi only devices which do not have an internal GPS chip.

To view a map for somewhere other than your current location, follow these steps:

1. Tap the Map List tab.
2. Tap the + button. Choose one of the methods to identify the desired map. Download it.
3. Scroll to the map you just downloaded.
4. Tap the map name.
5. A check mark will appear next to the name indicating that is the map you will view.
6. Tap the My Location tab once only. Do not tap it a second time.
7. You will be viewing your chosen map, starting in the center of the map. Pan and zoom to the area on the map that you want to see.
8. To resume viewing your current location, Tap the My Location tab with the map showing.

Almost all modern mapping programs accept GPS data in the GPX file format. Use iHikeGPS to email tracks, routes and waypoints to yourself or friends. The email has an attachment which can be imported into any application that will read GPX files. Or you can transfer the GPX waypoints, tracks and routes to your computer using iTunes File Sharing.

Send an email to your iPhone, iPad, or iPod touch with a GPX or LOC (Geocaching) file as an attachment. Use Mail to view the email. Press and hold the attachment icon to send the data in the GPX file to iHikeGPS.

You can also transfer the waypoints, routes, and tracks from your computer using iTunes File Sharing or Dropbox.

If you put the iPhone in your pocket or buried in your back pack while recording a track, your body or items in your pack may partially block GPS satellite signal reception. Sometimes that may not matter, but if you are already in an area with heavy tree cover, near the bottom of a narrow canyon, or in some other situation where GPS signal reception is more difficult, avoiding any further blocking of the GPS signal becomes important. A number of companies make arm-band holders for the iPhone which not only gets the iPhone out away from your body where it will have the best reception, but also gives you the hands-free ability to glance at the map on your iPhone screen whenever you want. Do a Google search for “iPhone armbands”.

You can change several settings to reduce the devices's drain on its battery. Adjust the following settings:

• Tap Wi-Fi, then Turn off Wi-Fi.
• Tap Bluetooth, then turn Bluetooth off.
• Tap Display & Brightness, then turn down the screen brightness to the lowest acceptable level.
• Tap “iCloud”, then tap “Documents & Data”, turn off “Use Cellular”.
• Tap “Mail, Contacts, Calendars”. Tap “Fetch New Data”. Turn off “Push” and tap “Manually” under Fetch.
• Tap “iTunes & App Store”, then turn off “Use Cellular Data”.

Also:

• Plug the iOS device into a car charger on your way to the trailhead so that you start the hike with a completely charged battery.
• On the Track Screen, select “Always”. Put the iPhone to sleep when you are not looking at it. When you stop for lunch or to enjoy the view, on the Track Screen select “Off”. (Don’t forget to turn tracking back on before resuming your hike.)

If you follow all the steps, you may be able to record tracks for about 10 to 12 hours of actual hiking. Use an external battery pack to extend this time.

Under normal operating conditions, the GPS chip in the iPhone or WiFi+cellular iPad receives signals from at least 4 GPS satellites to calculate the 4 parameters of latitude, longitude, elevation, and time. Sometimes, in a narrow canyon, thick vegetation, or an overhanging cliff, reception of 4 satellite signals may be impossible. When the GPS chip is receiving only 3 satellite signals, it assumes that the elevation stays constant, allowing it to still calculate the changing latitude, longitude, and time. During this period, the elevation profile graph will be flat. Once the GPS chip is receiving 4 or more satellite signals again, the elevation reading will re-register your current elevation. You can reduce the chances of not receiving enough satellite signals by keeping the iPhone or iPad in full view of a clear sky, unblocked by anything shielding it, such as your body or metal or water-filled items. The most recent iOS devices receive satellite signals from the Glonass satellites as well as the GPS satellites, greatly reducing the chances of this happening.

24K Quad Topo Maps are huge 34 to 65 megapixel images, which take a second to process given the speed of the iOS devices's processor. A spinning activity indicator will show in the upper right corner of the screen when the map cache is updating. This takes longer on the iPhone 3GS than it does on the speedier more recent models. Wait to give iHikeGPS further commands until the activity indicator is no longer visible.

With the introduction of iCloud, Apple requires iHikeGPS and other offline mapping programs to store the maps in the cache folder. That way the maps, which use several megabytes of memory each, would not take up space in your limited iCloud storage allotment. With the introduction of iOS 5, Apple started purging files from the cache folder whenever the the iOS device's storage memory was too full. If your maps disappeared, that means that you are almost out of storage memory and would benefit from removing some old apps you never use, some old songs you never listen to anymore, etc., to free up some memory and prevent further problems.

If your maps have been erased, each time you start iHikeGPS you will be given an opportunity to re-download your previously-downloaded maps. Be sure to do so before you download any new maps.