The present paper, through a series of methodological and scientific experiences, means to contribute to the use of IT in the archaeological field. A number of works in progress are exposed, in which different methodologies are related to different cases of study . Our analysis wants to be a moment of constructive criticism about the treatment of the spatial information. For any type of IT elaboration and spatial correlation, the attention must be focused on the objectives to reach and on the intrinsic characteristics of the experimental datum. In order to analyze and interpret the data set, it's necessary to know different methodologies and their instrumental errors. Through this type of analysis, it will be possible to perform dimensional and spatial comparisons that will allow us to use the datum, not only in qualitative but also in quantitative way. In this article some case of studies will be shown very interesting for the type of methodology used. In the archeological complex of Villamagna, near Anagni, the differential GPS has been used. The purpose of this work, was to get the DTM of the area near the archaeological excavations. In this survey differential GPS has been mounted on a off-road vehicle. Subsequently the orto - photo and its connected problems will be analyzed, i.e. the drawing of stratigraphic unity in relationship to the dimension of the photo and other related problems. Actually point clouds taken with Laser Scanner or photogrammetry, thanks to their precision, are innovative elements for the execution of an archaeological survey. Some examples related to the use of Laser Scanner and photogrammetry and belonging to current international projects will be shown: in the first example the Laser Scanner is applied to buildings of which a virtual navigation is figured. In the second case the photogrammetry (manual and automatic), through the use of braked aerostatic ballon, is applied to one of the most important monuments of Petra (Palace Tomb) and on the crusade castle of Shawbak. The purpose of the presented article is to show that a single methodology cannot be used everywhere and that very often we need to use a methodology that be related to the specific features of the site