  Astronomers performing polarimetric analysis on astronomical images often
have to manually identify locations on their objects of interest, such as
galaxies, which exhibit the influence of magnetic forces due to interaction
with their environments or inherent processes. These locations are known as
Lines of Sight (LoS). Analysing the various lines of sight can provide insight
into the electromagnetic nature of the astrophysical object in question and its
surroundings. For each LoS, astronomers generate diagnostic plots to map out
the variation of the corresponding electromagnetic field, such as those of
fractional polarisation and Faraday spectra. However, associating the different
LoS diagnostic plots to their positions on an astronomical image requires
alternating between the plots and the images. As a result, determining whether
the location of the LoS influences its magnetic field variation by analysing
its diagnostic plots becomes arduous due to the absence of a direct way of
linking the two. PolarVis is an effort towards allowing an almost instant view
of the interactive diagnostic plots corresponding to a given line of sight at
the click of a button on that line of sight on the image, using an interactive
web-based FITS viewer -- JS9.
