The Hough Stream Spotter (HSS) is a stream finding code which transforms individual positions of stars to search for linear structure in discrete data sets. The code requires only the two-dimensional plane of galactic longitude and latitude as input.

walter calculates the number density of stars detected in a given observation aiming to resolve a stellar population. The code also calculates the exposure time needed to reach certain population features, such as the horizontal branch, and provides an estimate of the crowding limit. walter was written with the expectation that such calculations will be very useful for planning surveys with the Nancy Grace Roman Space Telescope (RST, formerly WFIRST).