I had three key ideas when I started to code the program:
The original idea started from inventing the data collection method. First I considered using polar coordinates, because that would already be familiar to archers. With this I mean the expressions like "seven in five o'clock, nine in two o'clock" etc. The accuracy wouldn't be high enough, however. So I decided to draw a grid on the target, like a chessboard. The rows and columns are numbered with increasing values from the left to the right and from the bottom to the top.
You can either draw the grid on an existing target (tedious, but lasts longer) or print the target and the grid using the program. A plain copying paper does not last very long, but if you can use heavier paper (120g/m2 or more), this shouldn't be a big problem. If you need a target for longer distances, you also need a bigger paper; even A3 size is not quite enough for a 80cm spot target.
The more accurate you want to be, the more lines you must draw. Here you have a few options, however. Depending on your skills, the shooting distance etc., you can choose the span of the grid. For indoor testing at 18 metres, it may well be enough to use a grid covering only the nine-ring.
You can also increase the recording accuracy by writing down the sectors within a grid cell. The sectors are numbered from 1 to 8 clockwise, starting from the upper right sector. For example in the picture below I would call the hit as 4,5,3, where 4 is the x coordinate, 5 is the y coordinate and 3 is the sector.
After having created calculation methods for this grid system, I applied them to imported TargetPlot data. Actually, all that was needed was to invert the vertical axis, span the grid area over the whole target face and set 22 gridlines per ringwidth. The same method will most probably work with BowMate data, except the resolution will be substantially higher, 30 lines/ring.
Maybe the most natural way to enter data is to point and click them with the mouse. This requires the target face to be at hand. This is easy, if the target is small, especially when using the targets printed with the ArrowMaster program. Using the larger target faces is not practical in this purpose.
The increasingly popular digital cameras make it possible to record the arrow hits very quickly and easily, even in tournament situations. Just wait until other competitors have pulled their arrows from the target, then take the picture. There is one disadvantage, though: if the camera is not along the normal going through the target center, the picture is more or less distorted, the rings are not perfectly round.
The most accurate digitization can be achieved by using a scanned target picture. Then there are no distortions, and the holes made by the arrows can be marked with absolute precision.
At this point I have to mention that when I had started developing ArrowMaster, I found out the existence of the TargetPlot(tm) program for Palm(tm) computers. For data collection, it is naturally a very handy tool. It seems also to have many nice features, like scorekeeping, session notes etc.
What TargetPlot does not handle very well (yet?), is the statistical analysis. It does calculate the group centers, which is perhaps most important, but otherwise you're on your own. Future versions of TargetPlot may adopt features from ArrowMaster, which is quite all right, I don't mind :)
But to use the program, you have to own or purchase a Palm computer! For many archers, even purchasing new arrows is often a big step. I shot five (5) years with my first dozen ACE's, until only three of them were in shooting condition. My current arrows second-hand, but most of them seem to behave quite well.
If you do have a Palm, you should also consider trying BowMate. It may well prove to be easier to use and more versatile in scorekeeping respect.
The second 'unique' idea is based on fact that during arrow testing, there are usually many factors which obscure the true behaviour of the arrows.
First of all, the sight setting may be a bit off. Some arrows may hit the ten, some don't. You cannot be sure, by which ones you should adjust the sight until after a few rounds. It's easier to leave the sight untouched and let the program calculate, where the center of the overall group is.
If you are a 'normal' archer, some of your arrows occasionally go to the eight or worse. You're tempted to ignore these shots, but you shouldn't, because some part of the arrow direction may be a result of the arrow itself. You can let the program decide, which shots really do not belong to the pattern. Of course, you should exclude really bad shots right away (even if the arrow would have hit the gold).
For us average archers it is also common that each end is a bit different than the others. This may be caused by differences in the wind, lighting, stance, anchoring, release etc., but usually these differences are smaller during one end than between the ends. This is reason why the program treats each end as a whole.
The basic drawback of the pen-and-paper system is the difficulty to interpret the results correctly. You must test your arrows for a long time, before you can see the pattern emerge, and even then it may be hard to tell, which arrows are the best and most reliable.
With ArrowMaster, you can easily browse the hits by tests, ends or arrows and try filtering out the worst shots or arrows. This way it is quite easy to pick a set of arrows, which behave the same way.