  The century long (1914-2007) $H_{\alpha}$ (656.28 nm) spectroheliograms from
Kodaikanal Solar Observatory (KSO) have been recently digitised. Using these
newly calibrated, processed images we study the evolution of dark elongated on
disk structures called filaments, potential representatives of magnetic
activities on the Sun. To our knowledge this is the oldest uniform digitised
dataset with daily images available today in $H_{\alpha}$. We generate
Carrington maps for entire time duration and try to find the correspondences
with maps of same rotation from Ca II K KSO data. Filaments are segmented from
Carrington maps using a semi-automated technique and are studied individually
to extract their centroids and tilts. We plot the time-latitude distribution of
filament centroids producing Butterfly diagram, which clearly shows presence of
poleward migration. We separate polar filaments for each cycle and try to
estimate the delay between the polar filament number cycle and sunspot number
cycle peaks. We correlate this delay with the same between polar reversal and
sunspot number maxima. This provides new insight on the role of polar filaments
on polar reversal.
