Our Experience With Nomograms: Calculating Your Body Mass Index
Together with DataArt’s Data visualization competence center and Healthcare practice, we have developed an interactive application that functions on several platforms including desktop and mobile browsers and allows building nomograms.
See also: Mapping UK Prescriptions: Insider's Viewpoint.
A nomogram is a diagram representing the relationships between three or more variable quantities by means of a number of scales, so arranged that the value of one variable can be found by a simple geometrical construction, e.g. by drawing a straight line intersecting the other scales at the appropriate values. Nomograms are often used in Healthcare as a prediction tool to help patients and physicians make important treatment decisions.
As the basis for our application we’ve used the PyNomo library. PyNomo is a useful application which allows building custom nomograms of various levels of complexity. To build a nomogram one needs to create a custom Python script to define the nomogram. In our prototype we’ve enhanced the tool by building a convenient user interface and applying color coding to present the result in a more visual way, while the process of nomogram calculation itself still lies with PyNomo.
Example: the nomogram shows Body Mass Index. With the height of 1.8m and Weight of 70 kg BMI is 21.60 which lies within the acceptable range and thus is shown in green.
The prototype allows the user to interact with the nomogram by changing the height and the weight to see how it affects the outcome. Color coding is used here for the Body Mass Index axis to show whether the result lies within the advisable range or not.
The prototype functions on many desktops and mobile browsers including Chrome, Firefox, IE, and iPad Safari.
