a keyboard 17 fig2 and at the same time show up at a display 18 of the storage means 3 with this embodiment each of these six values in all four types of data blocks is specified by a two or three position alphanumeric code which has a mnemonic sense and is displayed at the same time with the respective value prior to being stored the several input values of each block are in a buffer storage means the content of which is displayed in a manner known from the stack register of pocket calculators fig3 after a roll down key is pressed the succeeding number is displayed without change of the order of numbers within the buffer for economic use of the memory capacity available a variable word length is provided as well as elimination of all information that repeats with successive measurements the structure of data memory 3 is represented schematically and in detail in fig3 the memory is subdivided into the data memory 19 proper and the two buffers 20 21 the content of data memory 19 cannot be altered by means of keyboard 17 whereas content of buffer 21 can be changed only by a store command preparation of the data blocks is effected with buffer 20 values no 1 to 3 of each block are transmitted automatically from the measuring station at the first survey point values no 4 to 9 are put into buffer 20 by means of keyboard 17 thus they may be arbitrarily changed while in buffer 20 buffer 20 comprises an additional register 22 which holds the running number of the respective.