A method for modeling an environment with a risk of nuclear contamination comprising steps of: a) acquiring, using a terminal comprising detection means and through a 3-dimensional displacement of the terminal in said environment: - information related to the topography of said environment and odometry data respectively by topography data acquisition means integrated into said detection means and by odometry data acquisition means integrated into said detection means and, - radiological measurement data of said environment, and then via computer processing means integrated into said terminal: - estimating path data at least from position and/or displacement measurements of said detection means, and at least from distance measurements between the detection means and one or more element(s) of said environment, b) associating said radiological measurement data with location data in said environment, said location data having been deduced from path data of said detection means, c) creating, using said information and via said computer processing means: at least one matrix in which topographic data of said environment and radiological data associated with the location data are compiled, and a 3-dimensional mapping representing said environment in which said topographic data and said radiological data are jointly represented, the mapping being developed in real time and being displayed on a screen of the terminal as it is developed. a) acquiring, using a terminal comprising detection means and through a 3-dimensional displacement of the terminal in said environment: - information related to the topography of said environment and odometry data respectively by topography data acquisition means integrated into said detection means and by odometry data acquisition means integrated into said detection means and, - radiological measurement data of said environment, and then via computer processing means integrated into said terminal: - estimating path data at least from position and/or displacement measurements of said detection means, and at least from distance measurements between the detection means and one or more element(s) of said environment, - information related to the topography of said environment and odometry data respectively by topography data acquisition means integrated into said detection means and by odometry data acquisition means integrated into said detection means and, - radiological measurement data of said environment, and then via computer processing means integrated into said terminal: - estimating path data at least from position and/or displacement measurements of said detection means, and at least from distance measurements between the detection means and one or more element(s) of said environment, - estimating path data at least from position and/or displacement measurements of said detection means, and at least from distance measurements between the detection means and one or more element(s) of said environment, b) associating said radiological measurement data with location data in said environment, said location data having been deduced from path data of said detection means, c) creating, using said information and via said computer processing means: at least one matrix in which topographic data of said environment and radiological data associated with the location data are compiled, and a 3-dimensional mapping representing said environment in which said topographic data and said radiological data are jointly represented, the mapping being developed in real time and being displayed on a screen of the terminal as it is developed.