Welcome to the MacNN Forums.

ghporter · Jul 28, 2009, 07:14 PM

I am looking for an iPhone app that provides the "julian day," also known as the "day of year," through the iCal "in the icon" interface. In short, with today being July 28, it's J-day would be 209 (31+28+31+30+31+30+28). The app I'd love to find would provide that in its icon the way that iCal provides "July 28" in its icon.

Adding in simple functions like "what's the date X days from now" or "what was the date Y days ago" would be cool too, and the math is incredibly simple for such calculations. These types of functions are very useful in planning all sorts of things, from regular scheduled backups to medication refills to planting seeds.

I'm pretty certain that Objective C has a method that returns the day of year (even Java and JavaScript do), but I'm way too rusty with programming to attempt to develop even this extremely simple app myself. I'm also not sure whether the iCal icon interface is part of the documented API.

So, is there an app that does this (without also calculating my last menstrual period) that doesn't cost more than $2? Or is this something that could be easily and quickly developed? Any support in this would be greatly appreciated.

Dork. · Jul 28, 2009, 07:37 PM

I found an app called "daynumber" which lists the Julian day when you open it. It's $1.00, but rather ugly. And doesn't do the (extremely useful) date calculations you want.

I'd recommend looking at Astronomy apps, although you have to be careful since some would list the Julian Date (the day count referenced to 4000ish BC) or the Modified Julian Date (referenced to Nov 1858) instead of the Julian Day you want (referenced to Jan 1 of the current year).

ghporter · Jul 28, 2009, 09:49 PM

I looked ad Daynumber a while back, and it's indeed very, very ugly, along with not doing anything else, even the trivial stuff. I had not mentioned the various "interfaith" calendars, but they too are not usable-they can convert five or six different types of calendars between each other, but they can't tell you how far into the year (in days) today is, nor how many days are left.

The astronomy calendars that I've looked at are a bust; they don't really allow the relatively short-term date calculations I'm looking for, and they do so much more that they sort of overwhelm the simple date stuff. And most of them are a lot more than $2, too.

kylef · Jul 29, 2009, 05:14 AM

I thought that application icons could only be changed whenever there is an update to the app. Are there any apps in the store that can do this?

Dork. · Jul 29, 2009, 07:27 AM

AFAIK, the Calendar app is the only app whose icon changes on the fly. It's possible Apple doesn't let mere mortal apps do that.

Maybe there are countdown (countup?) apps that can be used to count the days from a certain date? Set the reference point to Jan 1 of the current year and you're good to go....

(Can I ask what you need the Julian Day for, anyway?)

ghporter · Jul 29, 2009, 08:21 AM

Originally Posted by Dork.

(Can I ask what you need the Julian Day for, anyway?)

I spent something over 20 years using the Julian Day to figure all sorts of things. Since it was part and parcel of my military duties, not just recording the serial number of the day in maintenance documentation, but also planning future maintenance actions and so on, I became very used to this mechanism for determining past and future dates precisely. So when it's time to figure out when the next vet visit is due, when it's time to change the water filter in the fridge, and when it's time to check fluids in the cars, it's natural for me to want to find the date precisely using this mechanism... Fortunately this (so far theoretical) app isn't really a "necessity," but it would be very handy to have on my iPhone so I could do all this sort of planning on my phone's calendar.

Dork. · Jul 29, 2009, 08:33 AM

I wonder if I can get away with writing an app like this on work time..... probably not.

Luckily, my boss doesn't read MacNN.

kylef · Aug 1, 2009, 06:43 AM

Originally Posted by Dork.

AFAIK, the Calendar app is the only app whose icon changes on the fly. It's possible Apple doesn't let mere mortal apps do that.

Maybe there are countdown (countup?) apps that can be used to count the days from a certain date? Set the reference point to Jan 1 of the current year and you're good to go....

(Can I ask what you need the Julian Day for, anyway?)

The only way that I think it could be done now is using badge support, but that'd be pretty annoying to always have "23" followed by "22" then "21" etc. or whatever on an app icon.

fryguy · Oct 7, 2009, 12:11 PM

There is a new App in the app store called Julian Day - $1.99 It does more than DayNumber and not quite as ugly. But still no badge icon.

ghporter · Oct 7, 2009, 10:02 PM

Originally Posted by fryguy

There is a new App in the app store called Julian Day - $1.99 It does more than DayNumber and not quite as ugly. But still no badge icon.

I can't find that one no matter how I search. Who's the developer?

fryguy · Oct 12, 2009, 10:49 AM

Originally Posted by ghporter

I can't find that one no matter how I search. Who's the developer?

It called Julian Day and it's the same person who did Daynumber. Neal Layton

ghporter · Oct 13, 2009, 07:32 AM

Found it-by searching on the developer name. It looks like what I was thinking of-mostly-but he's priced it at $1.99! Sheesh! Not that $2 is a lot, but I'm surprised at how high the app is priced. Thanks for pointing it out.

alex_kac · Oct 13, 2009, 03:45 PM

Question - if a calendar app added Julien Days to its display - how would it look? I can see it for Week, Day, and List views - but not so sure about month. Would you want the Julien day instead of the month day number? or perhaps next to the day number?

Dork. · Oct 13, 2009, 03:51 PM

Folks who use the Julian Day usually use it to substitute for date and month. So today (Oct 13, 2009) is Day 286 of 2009. No month or week needed.

On a calendar, I would expect to find it in small text in the corner of the box for an individual day. I've seen it expressed as a count of both the current Julian date and the number of days left in the year. So Jan 1, 2009 would be 1/364, and Oct 13, 2009 would be 286/79.

Jan 1 2012 would be 1/365 and Oct 13 2012 would be 287/79, due to the leap day. If the world doesn't end by then.

alex_kac · Oct 13, 2009, 03:57 PM

Right - but visually you have a grid of cells for a month - think desk calendar. I suppose in that case instead of the day numbers for that month, you'd have a Julian number instead, right?

Dork. · Oct 13, 2009, 03:58 PM

I've seen desk calendars with both. Even if you are in a line of work that uses Julian dates, you're still interested in the more conventional month/day information. You might have the conventional date in larger print, and the Julian date in small print in the corner.

alex_kac · Oct 13, 2009, 04:05 PM

OK - thanks. That helps me a lot. I appreciate it. Next question - if you're picking a new date for an appointment would you be primarily interested in being able to pick the date by Julian dates (since there isn't room for both in most cases on-screen). Or better question - if you turned on Julian support in a calendaring app would the following be appropriate settings:

Julian Dates [ on / off ]
Show Julian Dates [ only / in addition to]
Use Julian Dates in Date Picker [ yes / no ]

Or perhaps some other combination? I don't like having too many prefs or too complicated set of prefs so the question above resolves itself to what is the minimum number of prefs that would add the feature to a calendaring app and be useful?

Hope you guys don't mind me doing some research here.

ghporter · Oct 13, 2009, 09:41 PM

An ideal Julian Day app screen icon a la iCal's would have the year in the red "month" spot and the J day in the day of month area, as in 2009/287 for today.

I've used both desk calendars with conventional dates and J days on them for decades; they're useful but very "desk bound." I've also used "perpetual" J day calendars that are basically a simple grid 12X31 with columns for months and rows for days so you find the month and run down the column to the day of the month to find the J day. Clumsy but easy and accurate. The front has "everything but leap years" and the back has "leap years" so you can't miss if you have just a tiny bit of training.

ctt1wbw · Oct 28, 2009, 04:16 PM

Originally Posted by ghporter

I spent something over 20 years using the Julian Day to figure all sorts of things. Since it was part and parcel of my military duties, not just recording the serial number of the day in maintenance documentation, but also planning future maintenance actions and so on, I became very used to this mechanism for determining past and future dates precisely. So when it's time to figure out when the next vet visit is due, when it's time to change the water filter in the fridge, and when it's time to check fluids in the cars, it's natural for me to want to find the date precisely using this mechanism... Fortunately this (so far theoretical) app isn't really a "necessity," but it would be very handy to have on my iPhone so I could do all this sort of planning on my phone's calendar.

Yes, the Julian date is what the supply department uses. That's all they use. I could never get used to it.

supermandt · Nov 12, 2009, 07:31 AM

Hi everyone, I created a new iPhone App - Julian Day Calculator that I hope you will all like. Here is a
Julian Day Calculator
If you have any suggestions on how to make it better or if there is something you would like to see, please let me know and I will add it to the app asap.

YouTube link so you can watch a video of it.
YouTube - iPhone Julian Day Calculator

Also, here is the iTunes Link
iTunes Store

Thanks.
Dave

msuper69 · Nov 12, 2009, 08:26 AM

What you want is an Ordinal Date app.

"The Julian date (JD) is the interval of time in days and fractions of a day since January 1, 4713 BC Greenwich noon..."

I've worked in Data Processing (now called Information Technology) for 40 years and was always annoyed at the incorrect reference from professionals I worked with who should know better.

ghporter · Nov 12, 2009, 09:24 AM

The entire DoD calls the "serial number of the day of the year" a "Julian day." I'm using terminology that's been in effect since the 1950s, whether it's technically, formally correct or not. Note that the term is not "Julian date," which is exclusively the territory of astronomers.

There are no "ordinal date" apps in the iTunes Store.

supermandt · Nov 13, 2009, 08:46 AM

Thanks for the suggestion. I will look into that too.

Dave

Our iPhone Apps
iPhone Apps by Dash Technologies

fryguy · Jan 14, 2010, 01:25 PM

Originally Posted by ghporter

I've used both desk calendars with conventional dates and J days on them for decades; they're useful but very "desk bound."

Just to bump this thread a bit, there is a new app in the App Store that uses a desktop "Calendar Style:" grid layout like you mentioned above to display Both the Julian Day and the Gregorian dates.
App Store link:
iTunes Store

Plus they have added this and a few other things to the original Julian Day app that is here:
iTunes Store

Timo · Jan 14, 2010, 02:43 PM

Originally Posted by Dork.

I wonder if I can get away with writing an app like this on work time..... probably not.

Luckily, my boss doesn't read MacNN.

Yes I do; get back to work.

Dork. · Jan 14, 2010, 03:08 PM

Sorry, Boss, I'm on my "I don't give a ****" break.

We should get a 8.49% discount on all these Julian Day apps (8.46% during leap years), since calculating the Julian Date is trivially easy for January.

ghporter · Jan 14, 2010, 09:31 PM

Originally Posted by fryguy

Just to bump this thread a bit, there is a new app in the App Store that uses a desktop "Calendar Style:" grid layout like you mentioned above to display Both the Julian Day and the Gregorian dates.
App Store link:
iTunes Store

Plus they have added this and a few other things to the original Julian Day app that is here:
iTunes Store

The new app looks pretty nice; I have decided to dive in and buy it. I've just downloaded the "Day Number Free" app and I'll play with it for a bit too.

fryguy · Jan 15, 2010, 05:31 PM

Originally Posted by ghporter

The new app looks pretty nice; I have decided to dive in and buy it. I've just downloaded the "Day Number Free" app and I'll play with it for a bit too.

The free one works great, but I find my self launching it multiple times per day, which is a pain. So I upgraded to the regular 99cent version and it allows me to put the badge icon on with the day number on it, So once each day I launch it then every other time, all I have to do it just look at the phone. It's excellent............but it still needs one feature. Auto updates of the icon badge. If I didn't have to launch it once per day and it just updated every night at midnight it would be better.