  The exotic internal structure of polar topologies in multi-ferroic materials
offers a rich landscape for materials science research. As the spatial scale of
these entities are often sub-atomic in nature, aberration corrected
transmission electron microscopy (TEM) is the ideal characterisation technique.
Software to quantify and visualise the slight shifts in atomic placement within
unit cells is of paramount importance due to the now routine acquisition of
images at such resolution. In the previous ~decade since the commercialisation
of aberration corrected TEM, many research groups have written their own code
to visualise these polar entities. More recently, open access Python packages
have been developed for the purpose of TEM atomic position quantification.
Building on these packages, we introduce the TEMUL Toolkit: a Python package
for analysis and visualisation of atomic resolution images. Here, we focus
specifically on the TopoTEM module of the toolkit where we show an easy to
follow, streamlined version of calculating the atomic displacements relative to
the surrounding lattice and thus polarisation plotting. We hope this toolkit
will benefit the rapidly expanding field of topology based nano-electronic and
quantum materials research, and we invite the electron microscopy community to
contribute to this open access project.
