A method, performed by an apparatus (2-1, 2-2, 3), said method comprising: - generating or obtaining (501, 601, 601', 801) detection data, said detection data comprising: - position data that is indicative of a position of a terminal (2-1, 2-2) and - one or more identifiers respectively related to one or more coverage areas detected by said terminal (2-1, 2-2), and - detecting (502-504, 802-804) a negative hit for at least a region of a coverage area representation (4-10, 4-20) associated with a coverage area, if at least all of the following conditions (i)-(iii) hold: (i) a class of said coverage area matches at least one class of one or more coverage areas for which respective identifiers are comprised or at least expected to be comprised in said detection data, (ii) said position of said terminal (2-1, 2-2) is within said region, and (iii) said detection data does not comprise an identifier related to said coverage area associated with said coverage area representation(4-10, 4-20), - using and/or providing at least information on said detected negative hit for deciding if said region of said coverage area representation (4-10, 4-20) shall remain part of said coverage area representation (4-10, 4-20) or shall be removed from said coverage area representation (4-10, 4-20), and/or for deciding whether a frequency of generating detection data shall be increased; further comprising: - increasing (505, 609, 607') a negative hit counter maintained for said region of said coverage area representation (4-10, 4-20) if a negative hit for said region of said coverage area representation (4-10, 4-20) is detected, wherein said information on said detected negative hit is said negative hit counter. - generating or obtaining (501, 601, 601', 801) detection data, said detection data comprising: - position data that is indicative of a position of a terminal (2-1, 2-2) and - one or more identifiers respectively related to one or more coverage areas detected by said terminal (2-1, 2-2), and - position data that is indicative of a position of a terminal (2-1, 2-2) and - one or more identifiers respectively related to one or more coverage areas detected by said terminal (2-1, 2-2), and - detecting (502-504, 802-804) a negative hit for at least a region of a coverage area representation (4-10, 4-20) associated with a coverage area, if at least all of the following conditions (i)-(iii) hold: (i) a class of said coverage area matches at least one class of one or more coverage areas for which respective identifiers are comprised or at least expected to be comprised in said detection data, (ii) said position of said terminal (2-1, 2-2) is within said region, and (iii) said detection data does not comprise an identifier related to said coverage area associated with said coverage area representation(4-10, 4-20), (i) a class of said coverage area matches at least one class of one or more coverage areas for which respective identifiers are comprised or at least expected to be comprised in said detection data, (ii) said position of said terminal (2-1, 2-2) is within said region, and (iii) said detection data does not comprise an identifier related to said coverage area associated with said coverage area representation(4-10, 4-20), - using and/or providing at least information on said detected negative hit for deciding if said region of said coverage area representation (4-10, 4-20) shall remain part of said coverage area representation (4-10, 4-20) or shall be removed from said coverage area representation (4-10, 4-20), and/or for deciding whether a frequency of generating detection data shall be increased; further comprising: - increasing (505, 609, 607') a negative hit counter maintained for said region of said coverage area representation (4-10, 4-20) if a negative hit for said region of said coverage area representation (4-10, 4-20) is detected, wherein said information on said detected negative hit is said negative hit counter.