II.5. Histograms

To construct frequency distribution (histogram) of minor planets according to value of some element/ parameter/ function user should first select Elements item in menu bar and then Histogram in drop-down menu. Specify the element with the help of Select element list box. Select necessary element by slider and click on Next. Subsequently, the Limits dialog box will appear.

For the ordered element/ parameter/ function (its designation is shown in the upper part of the box) the application computes minimum and maximum values within the selection specified earlier when entering the table of elements. Moreover, possible step of histogram is indicated in the Step field. User can adopt all of them (click on OK) or change them at will. In many cases step can be taken on the order of one-hundredth part of the interval between minimum and maximum values. But it is desirable to take step as a multiple of the unit of measurement or so that the unit is to be exactly divisible by step value. In case step is too small the corresponding diagnostic appears. By changing adopted minimum and maximum values and step one can obtain the most expressive histogram.

After clicking on OK the graphical representation of distribution will appear.

At the top of window the designation of element is shown, followed by the limitative values of the element as they were specified by user, the step of histogram, the arithmetical mean of records, number of records, N, and the median of the distribution (value of the record with number N/2 in case N is even or [N/2]+1 in case N is odd in the sequence of records sorted in increasing order).

If you like to change currently used colors for background, histograms or fonts used for coordinates, inscriptions etc, select Histogram in task bar and then select Options...in drop-down menu. In the Histograms: Colors and Fonts dialog box choose parameter needed and change it in accordance with available examples of colors, fonts, sizes, etc. and press OK button.

User has possibility to save histogram or to print it using standard means. To save the file select File item in menu bar and then Save As... in drop-down menu. The only possible type of extension for saving file with histogram is ".emf" (it is actual in default of specification). Choose a drive and folder where you want to save the file. The list of files with extention ".emf" in chosen folder will appear. Mark necessary file in the displayed list if you like to change its content (name of the file will appear in the File name field of the dialog box) or insert new name in the field. Click Save button to save the file.

To print histogram select File item in menu bar and then take advantage of options Print Preview, Print Setup, Print.