ViewRanger is a free app that runs on a variety of smartphones; Apple, Android and various other phones are supported. Check here to see if your phone will work with ViewRanger http://www.viewranger.com/en-gb/features/supported-phones This free app turns your compatible phone with a GPS chip into a functioning GPS unit. You download the app from this page http://www.viewranger.com/en-gb/
The ViewRanger app works with a range of mapping including free sources, such as OpenStreetMap and premium (paid) products such as EastWest Mapping maps which are a lot more detailed. The maps are available either here http://shop.viewranger.com/products.php?category_id=59 or by download from within the ViewRanger app. Once installed, run the app and do a search in the Store for products using search term 'eastwest'. The Dublin & Wicklow mapping covers c 1500 km2 and costs c€50. The Blackstairs & Mount Leinster covers c 650 km2 and costs c€20. Prices are in sterling so may fluctuate slightly.
There are two facets to the ViewRanger product; firstly the app which runs on your phone and allows it to function as a handheld mapping GPS unit and secondly a website component called www.my.viewranger.com Here you can view your purchased premium maps and use them in a desktop situation to plan routes, print out map sections etc. There are also facilities to upload your saved walks and search for routes etc. posted by others in the community. Please note that as of 25 Oct 2013 this web feature is only partly implemented for EastWest maps to extent that maps are visible only when you zoom in. ViewRanger are making updates in coming weeks and will integrate them fully.
Please note that ViewRanger runs very well on many smartphones and is a cost effective way to have a GPS solution for your walking navigation. However there are some drawbacks and precautions need to be taken. The majority of smartphone devices are not designed to be weatherproof, rugged or have swappable batteries – the sort of features that you might require when hillwalking. You need to take these factors into account:
– weatherproofing, use a small purpose made waterproof holder on a lanyard around your neck. I have tested the Aquapac products and find them to be reasonably priced & effective. https://store.aquapac.net/explore-product-range/waterproof-phone-cases.html
– battery power, use the various PowerSave options within the ViewRanger app. Charge your phone fully before setting out. Turn off services like Wi-Fi and Bluetooth etc. Close down any other apps running in the background. Turn the screen off when not using ViewRanger. You may also choose to carry some form of (fully charged) additional mobile phone battery unit. With careful use, you'll get a good days walking navigation out of it.