Geology is, from its foundation, a subject study strongly based on field studies.
Nonetheless, offsite studies can frequently play a relevant role in surveying large areas and in preliminary assessments of specific sites, and they could give important contributions to the planning of onsite works.
In this communication are considered diverse online tools, including topographic and geological maps, satellite images and onsite images (Google Street View), which are freely available and can be integrated into a GIS environment (QGIS was used in the present work).
The potential and limitations of these tools will be discussed in the context of subjects relates to Environmental and Engineering Geology, being the discussion supported by some case studies related to examples of these issues, based on observations of terrains (including observations of built structures). Diverse perspectives will be considered, such as restraints to structures development, hazard assessment and hydrological studies, as well as the potential of sites for the teaching of concepts related to these subjects.