rename shapefiles folder
move population file to "input"
ignore contents of 'output' folder
iterate cities
print centroids
iterate parks; transform coordinates
print nearby parks
load population data
print city population
ignore entire output folder
create flux layer
read parks separately and save in memory
draw lines with hiker flux
rename function
extract function to fetch parks data
extract function that calculates hikers
parametrize max distance
calculate borders from postgis data
calculate densities and save as new layer
don't forget to close the connection