When loading a dataset (by Choose a file
or Load test dataset
), you have to select the temporal columns, i.e., the columns to be used for the mean growth computation.
Those columns must have a header containing their date, in numeric format (i.e. 1954 and not "POP1954")
As soon as data are loaded, they're displayed in the Base Data
tab, and a table containing the mean growth for each period is also computed. This table can be seen in the Growth
tab, along with it's standard deviation, and a plot representing it's evolution (the polygon around the curve represent +/- 1 standard deviation).
The Simulation
tab then allows to perform some Gibrat simulations, i.e. a computation where, starting from first observed populations, we compute randomly, for each period, a growth rate for each city. Those growth rates are based on a normal distribution around the observed mean and standard deviation.
Computation – although optimised to run on each core of the server – can still be long, so, start with a low number of replications (the default 10 for example) and grow according to the time it takes.
For any question, feel free to contact me
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