App Store Icon Rendering Change

The Oz Weather v1.3.1 update was approved and appeared on the app store today.

This version is a maintenance release only (no new features added), but does have some changes which will improve the user experience significantly.

  • It has a faster load time – at least 2 seconds faster than v1.3
  • The splash screen now matches the user-selected theme
  • Sunrise/set times and some other options are now switched on by default, instead of requiring user to go into Settings on their iPhone

However, one completely unexpected change is in the appearance of the app icon. Although no changes were made to the icon or to the entry in Info.plist which instructs Apple not to add any shine, the icon now appears with a lot of added shine and a new bevel or border.

Icon changes

I’m not sure whether the new appearance is an improvement or not. My initial reaction is that the shine effect is too strong. However, I’m sure our users will let us know one way or the other! And that’s something I love about being an app developer. Really, I do mean it. 🙂

Stop Press

According to @stroughtonsmith (twitter): “Always re-upload your large icon art after you update your binary, or it will ignore your UIPrerenderedIcon key and add gloss.”

After doing this, and waiting several hours for the changes to propogate through the app store, the appearance of the icon has now reverted to normal. It appears that the bevel or border effect was an artefact of the additional shine.

So other app developers take note! If you switch off icon rendering, remember to re-upload your large icon art work each time you update your binary.


Estimating App Sales From Rankings – Part 2

In an earlier post I showed a graph of Oz Weather’s daily sales levels versus its ranking in the Australian iTunes app store, and then extrapolated the findings to get a very rough estimate of global sales versus iTunes US app store rankings.

Australian Sales vs Rankings

As Oz Weather has now been selling for more than 3 months, and has had an extended period ranked #1 in the Australian store, so I am now in a position to make an enhanced analysis. But note that there were some anomalous sales figures over the Christmas period (24th Dec to 31st Dec) due to three unusual circumstances:-

  • the surge in overall Christmas sales
  • the fact that I discounted the app over that period
  • thirdly due to a major loss of sales when the app store broke down temporarily

The graph below shows the entire history of sales, minus that week’s worth of  “anomalous” sales data.

Sales Rankings Australia

I tried fitting logarithmic, exponential and power curves to the data – the power curve gave by far the best fit, with the approximate equation

Daily Sales = 425 * Ranking ^ -0.5

This equation can be used to give a reasonable estimate of sales of paid apps in the Australian iTunes app store using the overall ranking (not the ranking in any individual category such as entertainment, lifestyle, weather etc). However note that there is a wide range of variation about this mean trend line on a day to day basis. For example while Oz Weather was ranked #1 sales varied between about 260 and 620, and at rank #2 from 190 to 420.

World Sales versus Rankings

We now have a good idea of the apponomics of the Australian store, but what about world-wide sales? To begin to answer this, I have gathered as much data as I could find  giving US store app ranking versus daily sales. The main sources I found were

Using data from these sources – some real sales figures and others inferred and estimated, I constructed the following graph. 

Sales Ranking World

The main assumption here is that US rankings reflect Worldwide rankings reasonably well, which although not necessarily true for specific apps, is probably true on average. Also note that, to clarify the picture, I did exclude some of the higher figures given for #1 ranking – up to 50,000 or more supposedly. I suspect that sales at the #1 spot will be much more variable than lower ranked slots, so it seemed sensible to include only the lowest figures that resulted in a #1 ranking, for this purpose.

As before I tried fitting logarithmic, exponential and power curves to the data – and again the power curve gave by far the best fit, with the approximate equation

Daily Sales = 15000 * Ranking ^ -0.75

This equation can probably be used to give a reasonable estimate of sales of paid apps in the US iTunes app store using the overall ranking. It roughly confirms my earlier guess that world sales were typically 30 times more than Australian sales. In fact, for the given equations, the World/Australia sales ratio varies from 35 (#1 ranking) to 13 (#50 ranking).

Given that there is no reason to suspect any major difference in sales dynamics, one might have expected the ratio to remain similar at all rankings (ie. the power factor to be the same in each equation). However, note that the Australian curve is based on data only going down to #17 ranking, whereas the US curve has data down to #100 ranking. I therefore suspect that the US curve power factor is more realistic for the long tail, and that the drop-off in sales levels for Australia well below the #20 ranking might be somewhat less than that predicted by the given equation.

So there you have it – the best that I can do with the available data. As more data becomes available I will add it in to the mix, to see how much further this can be refined.

Oz Weather Apponomics – Part 3

Following on from Apponomics Part 1 after the first two weeks of sales and Apponomics Part 2 after one month of sales,  Oz Weather has now had just over three full months of sales. Here is a complete history of the daily unit sales numbers, up until 5th Feb 2009.

Sales to 5th Feb 2009

The red and yellow bars show Australian and overseas daily unit sales at AUD$2.49 (US$1.99), and the blue and orange bars are at the temporary sale price of AUD$1.19 (US$0.99).

I’ve annotated the graph with some significant events which did (or might have been expected to) affect sales volumes. These events were as follows.

  • Release of v1.1 Update – saw an immediate jump in sales and rise in ranking from #6 to #3
  • Release of v1.2 Update – sales flat
  • Xmas Sale – decided to try a brief sale over Christmas period due to falling sales & ranking having dropped to #9
  • App Store Broken – a couple of days when customers were unable to purchase Oz Weather
  • Major Heatwave in Parts of Australia – consistently high sales level, bringing ranking to #2
  • Release of v1.3 Update – major app enhancements and an eye-catching new icon pushed the Australian iTunes paid app ranking to #1 – where it remains at time of writing

Summary of Sales & Revenue

  • Total units sold: 23,800
  • Average sales per day: 245
  • Approximate revenue: AUD$35,000 (US$22,500)

Upgrade Statistics

  • Total units sold prior to v1.3: 19,800
  • Total upgrades to v1.3 in 9 days since release: 13,350
  • Upgrade ratio: 67.4%


Although I indicated in a previous blog entry that I had broken even on 19th December, I did invest considerable extra development time and effort into the latest app update, and also into further professional design work . Consequently I estimate my total nominal costs so far to be around the AUD$25,000 (US$16,000) mark. This leaves a nominal profit to date of AUD$10,000 (US$6,400).

Thoughts and Comments

Although Oz Weather has been substantially profitable (for a sole developer) over this 3 month period, the apponomics depend to a large degree on how much ongoing additional development effort is required to maintain its level of sales. So far, Oz Weather sales levels have not dropped off in a way that seems to be typical of many other apps. It remains an open question as to how much of this is due to the additional development effort I have made versus what would have happened without this frequency and depth of app updates.

Competition is of course another important factor. Whilst Oz Weather has taken the major share of the Australian Weather apps market since its launch, the visibility of its success is an encouragement to competitors. The developers of Pocket Weather have made no secret of the fact that they would very much like to regain the position they had in the app store before Oz Weather jumped in, and appear to be investing considerable time and effort into fighting back with their own major updates. There also remains the possiblity if not likelihood that some other major player in the Australian weather scene will want to launch their own app, backed with pre-existing infrastructure which will give them some competitive advantages.

So despite all the stories you might hear about overnight successes in the app store, overnight falls from grace are probably just as frequent. In reality, it is just a reflection of life as a whole. Hard work and listening carefully to your users will maximize your chances, but the only real certainty is uncertainty! Stay tuned for the next instalment.