The use of Geographic Information Systems (GIS) has spread to several science areas, from oceanography to geotechnics. Its application in the urban mapping was intensified in the last century, which allowed a great development, due to the use of geographic database, new analysis tools and, more recently, free open source software.Geotechnical cartography struggle with a permanent and large environment re-organization in urban area, due to new building construction, trenching and the drilling of sampling wells and holes. This creates an extra important and largest volume of data at any pre-existence geological map. The main problem results on the fact that the natural environment is covered with buildings and communications system. The purpose of this work is to create a viable geographic information base for geotechnical mapping through a free GIS computer program and open source, with non-traditional cartographic sources, giving preference to open platforms. QGIS was used as software and “Google Maps”, “Bing Maps” and “OpenStreetMap” were applied as cartographic sources using the “OpenLayers plugin” module. Finally, we also pretend to identify and delimit the degree of granite’s change and fracturing areas using a “Streetview” platform.This model has cartographic input which are a geological map study area, open cartographic web archives and the use of “Streetview” platform. The output has several layouts, such as topography intersection (roads, borders, etc.), with geological map and the bordering area of Guarda Urban Zone. The use of this platform types decrease the collect data time and, sometimes, a careful observation of pictures that were taken during excavations may reveal important details for geological mapping in the study area.