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Hillnav GPS on the App Store

Hillnav GPS is a fairly basic iPhone application targeted at hill walkers in the UK and Ireland. Hill walkers tend to make use of ordnance survey maps and a compass to navigate their way around unfamiliar areas, and some use a GPS device which displays their current location in a grid reference format.

I decided it would be an interesting exercise to use the iPhone to display the same grid reference, and in doing so create a fairly niche iPhone application. Niche applications, I heard, are the way to riches in the iPhone App store.


Attempting iPhone development for the first time, my first challenge was figuring out how iPhone development worked. Coming from a database and web development background, some of the concepts were a bit strange at first, but it didn't take long until I was up to speed.

The second challenge was figuring out how to translate a GPS coordinate into a UK or Irish grid reference. It turned out this was particularly tricky, and involved a lot of mathematics I still don't pretend to understand. After pouring over datasheets and some sample code for many hours, I got something that worked, or at least I thought it did.


The problem with an App that displays your location, is that it can be difficult to figure out how accurate the reading actually is. Luckily I managed to borrow a Garmin eTrek GPS device and used it side by side with my iPhone app. After fixing a few bugs, I proved my app was giving the same location as the consumer devices to within about 5 meters, which is more than accurate enough for hill walking.


The riches haven't quite arrived. I tried it on the app store at £1.99 and in about 2 weeks I had zero sales. Then I made it free for a week and advertised it on my Facebook account - that got me a few downloads. After that I set it to 69p, and after about 2 months I have got about 25 paid downloads. Better than nothing, but not much better.

25 sales amounts to about £10.50 in "profit", but then I had to pay Apple £60 for the privilege of placing the app in their store. Still, it feels good to make my first pound from the sale of my own software.

The Future

When I started building Hillnav GPS, my target was to learn iPhone development and create an app I needed for myself. Now that I have it working, I am keen to get others to use it (and pay for it) too. As of now, my marketing efforts have been close to zero, proving once again that putting a niche app in the store isn't a path to riches all on its own. As the spring approaches, along with hillwalking season, I will try and promote the app to some hill walking groups and see if I can get any traction.

I also have a few features I would like, so if my marketing efforts show any promise, I will spend some time making more improvements to see if it helps sales any.

More iPhone Apps?

Making money from iPhone development is tough. At 42 pence proceeds from a 69 pence sale, it takes a lot of sales to pay rent. I did find making the app enjoyable, and I learned some new skills. I haven't decided yet on my next project, but it is likely it will be a web application where I have the potential to charge a bit more money - I just need to think of the idea first!