In analysing geographic phenomena, the theory of "choremes" assumes a definite point of view comparing "choremes" to linguistic signs. The comparison is imperfect because choremes are not conceived for purposes of communication. Nevertheless, a certain ambiguity is evident in their conception. They may on occasion be applied to geographic objects or to geographic schema which facilitate their cartography. The consequences of the confusion between the "choremes" and its graphic representation are analysed using two graphics found in the publications of Roger Brunet and Robert Ferras: contact zones (aires en contact) and punctual evolution (évolutions ponctuelles). A tégéo (contraction of theory of geography) is a geographic sign whose meaning indicates a geographic object comprising an indissociable pair (information, place) differentiated on the earth's surface. The tégéo is expressed using a representation the design of which follows a prescribed logic.