get_obs_dens {geocausal} | R Documentation |
Generate observed densities
Description
'get_obs_dens()' takes a hyperframe and returns observed densities. The output is used as propensity scores.
Usage
get_obs_dens(hfr, dep_var, indep_var, ngrid = 100, window)
Arguments
hfr |
hyperframe |
dep_var |
The name of the dependent variable. Since we need to obtain the observed density of treatment events, 'dep_var' should be the name of the treatment variable. |
indep_var |
vector of names of independent variables (covariates) |
ngrid |
the number of grid cells that is used to generate observed densities. By default = 100. Notice that as you increase 'ngrid', the process gets computationally demanding. |
window |
owin object |
Details
'get_obs_dens()' assumes the poisson point process model and calculates observed densities for each time period. It depends on 'spatstat.model::mppm()'. Users should note that the coefficients in the output are not directly interpretable, since they are the coefficients inside the exponential of the poisson model.
Value
list of the following: * 'indep_var': independent variables * 'coef': coefficients * 'intens_grid_cells': im object of observed densities for each time period * 'estimated_counts': the number of events that is estimated by the poisson point process model for each time period * 'sum_log_intens': the sum of log intensities for each time period