# Documentation for the supplementary data of Lagain+ 2021 "Latitudinal dependency of the impact rate: 
any room for a recalibration of crater chronologies ?"

## relative_density folder
The folder relative_density contains the code and data (crater databases and shapefile areas) 
used to compute the relative crater density and associated presented on Figure 2.


## rate_ratio_test folder
The folder rate_ratio_test contains all the inputs used in the rate ratio test
and results.

## Crater counting data file 

The file crater_counts_5deg_latitude_bins.csv
contains all the counting and de-biasing data used in this study,
binned in 5 degrees bands on each planet, 
and seperated into 4 crater size bins.


Columns meaning:
latitude: center of the latitude band considered.
area_planet: surface area (km^2) considered on the planet.
count_planet_N: number of craters in the Nth size bin found on the area considered on the planet. 
r_planets_N: crater density in the area considered on the planet for the Nth size bin.




## Crater size bins look up table
The file crater_sizes_bins.csv
is a look up table of which bin (1st, 2nd, 3rd, 4th) in the crater count data
corresponds to which crater size on each planetary surface.
Example: 1st bin size for Venus corresponds to craters >3.04 km.





## Statistical tests files

The files called planet_latitude_dependence_ratio_test_*_bins.csv
give rate ratio test results for a selection of latitude bin sizes.

The columns follow the same naming principle as the counting data file.
An extra latitude column explicitates the bounds of the considered latitude bin (eg. [-90.0, -73.636]).

For each (count, surface area) tuple, we provide the key parameters of the statistical test question:
    "Is the considered area significantly more cratered than the equator?"

ratio_min_planet_N & ratio_max_planet_N: confidence interval for the cratering densities ratio of surface / equator, at 2 sigma confidence.
p_value_planet_N: p-value for the test.
