Following a flow cytometric analysis in which multiple parameters are measured, we attempt to visualize the position of each of our cells within the resultant multi-dimensional data space. However, given our inability to display more than 3-dimensional data directly, we are led to explore means of enhancing the quantity of visual information conveyed by the usual graphical displays that may depict 2-dimensional or 3-dimensional projections of the data. One common example of such an enhancement is the colour coding of 2-D dot plots.
In the current work, a technique is evaluated for linking two displays by means of the selection of a common subpopulation. It is implemented as follows: An initial display may be a 1-dimensional histogram or 2-dimensional dot plot or contour display. A region drawn in this display selects a cellular subpopulation, the data for which can be re-displayed as a separate 1-, 2- or 3-dimensional plot in any of the usual formats. Different flow cytometric parameters will be chosen for this ÒlinkedÓ plot than for the initial display. The user then drags the selecting region over the initial plot in a systematic way as determined by the form of the data as the changing subpopulation is plotted in the linked display. The graphical sequence can be saved as a movie or other animated form so that in repeated replay, the trends may be seen more easily. Linking two displays in this way may reveal correlations among as many as 5 parameters of a data collection. It is also possible to connect to multiple linked displays to further expand the number of parameters involved. This technique has been implemented as a component of the WEASEL general-purpose data analysis program.