Lesson 8 - Bullet analysis of data

Now that you have prepared and loaded a custom setup file, you are ready for custom data analysis. There are four methods to custom analyze data in Wintrack. The first, bullet analysis, produces graphical output and is introduced in this lesson. The other three methods (profile, trial, and case analysis) produce numerical results and are discussed in the following lessons.

Creating bullets in a case document...

1. Open the two sample case documents SWIM1.WTR and SWIM2.WTR of your WINTRACK folder. Make SWIM1.WTR the active document, maximize it by clicking the Maximize button of its window.
2. Load the custom setup file POOL3.WSP which you find in the WINTRACK directory of your hard disk.
3. Click the Analyze Custom button of the toolbar while pressing and holding down the Shift key. The Analyze Case Document dialog is displayed:
   • Note that most of the dialog fields are in a grayed state indicating that their contents will be ignored.
   • Press the button which is associated to the option from custom file in order to open a Windows™ standard File Open dialog box. Pick the file BULLET1.VDF in the WINTRACK directory and click Ok.
   • Set the dialog field labeled Report to None. There is no need to create a scrollsheet, because bullet analysis produces no numerical results.
   • Click Ok to close the dialog box and start the analysis.
4. BULLET1.VDF tells Wintrack to draw colored bullets to the case document to graphically represent periods of passive floating. The file is processed and the case window redrawn with colored bullets indicating floating periods. The duration of floating periods is color coded: yellow bullets indicate short floating periods, red bullets indicate longer floating periods.
5. If you wish, you can now print the case document with the bullets or export it to a Windows™ graphics application via the clipboard.

Editing the variable definition file...

1. Click the Analyze Custom button of the toolbar while pressing and holding down the Shift key. The Analyze Case Document dialog is displayed. The dialog field next to the option from custom file still shows name and path of the custom variable definition file BULLET1.VDF.
2. Click the NotePad… button located next to it. Wintrack starts Windows™ NotePad and lets it load the file BULLET1.VDF. It should look something like this:

   Bullets, example 1
   
   [variables]
   
   Matrix Data=Speed
   Exclude Rule=All
   Include Rule=Less Crit=0.06
   
   Matrix Data=Time
   Include Rule=Cluster Crit=1
   Transform Mode=ClusterSum
   Include Rule=Ons
   
   Bullets
    MinVal=1 MaxVal=20
    MinBullet=BulletY
    MaxBullet=BulletR
   
   Bullets
    MinVal=20 MaxVal=120
    MinBullet=BulletR
    MaxBullet=BulletR
   
   [end] 

   • All text above [variables] is free commentary. Between [variables] and [end] are the statements which define the sequence of analysis.
   • The first Matrix statement creates a temporary data matrix in which each trial is represented by a column and each data point by a cell. Cell values represent local Speed. The Exclude statement deselects all cells in the matrix, the following Include statement then re-selects all cells with values <0.06 m/s, that is points with passive floating.
   • The second Matrix statement fills the cells of the data matrix with Time values (the difference between the time stamp of the current and the previous data point). The following Include statement first sums the cell values within clusters of contiguously selected cells in each column. Then, it deselects the cells of all clusters whose sum is <1. This serves to disregard all floating periods shorter than 1 s. The Transform statement replaces the content of all selected cells with the sum of all cells in the cluster they belong to. The last Include statement deselects all cells but the first cell of each cluster of selected cells.
   • The first Bullets statement draws bullets for cell values between 1 and 20. The bullet named BulletY is picked up in the currently loaded custom setup file and drawn over all points whose matrix cell is selected and contains the value 1. Similarly, the bullet named BulletR is drawn on top of points whose cell is selected and contains the value 20. For points whose cells contain values between 1 and 20, a linear interpolation between BulletY and BulletR is performed. The second Bullet statement finally draws BulletR on top of all points whose matrix cell is selected and contains a value of 20 or more.
3. After having reached the platform, animals often sit there for a while before recording is stopped. We do not want this to be shown a floating. To change this add the following text above the second Matrix statement:

   
   Include Rule=Less Crit=0.06
   
   Matrix Data=DistBder Field1=Goal
   Exclude Rule=Greater Crit=-.05
   
   Matrix Data=Time

   • The new Matrix statement references the field named Goal in the in the currently loaded custom setup file. It writes the distance between every data point and the border of the goal to the point's data matrix cell. If the point is outside the goal, the values are negative, else positive. Remember that the goal position is not the same for all trials. This does not matter, however, since Goal is referenced by name and the correct positions are given for all trials in the custom setup file.
   • The following Exclude statement deselects all matrix cells with values > -0.05, that is points that are less than 5 cm away from the platform border.
4. From the File menu of Windows™ NotePad, select Save As and save the edited setup file as BULLET2.VDF. Terminate Windows™ NotePad. You are put back into the Analyze Case Document dialog:
   • Press the button to open a Windows™ standard File Open dialog box. Pick the file BULLET2.VDF you have just created in the WINTRACK directory and click Ok.
   • Click Ok again to close the dialog.
5. Wintrack processes the file and redraws the case document with the new bullets. Now, select the document SWIM2.WTR from the Window menu to activate it and bring it to the foreground.
6. Click the Analyze Custom button of the toolbar without pressing the Shift key. The Analyze Case Document dialog is bypassed and Wintrack directly applies the most recently run analysis to the new document. In our example, it processes BULLET2.VDF. As you can easily see, floating was a lot more frequent in this case.

Note

You might already have noticed that statements in custom variable definition files (and in custom setup files) may be typed in two ways: either on one line with spaces as separators between the components of the statement, or broken into two or more lines. If you place components of a statement on a new line make sure that the new line begins with at least one white space. Or else Wintrack will consider the line as the beginning of a new statement which most likely will result in an error message.