Analyses and syntheses conducted before the urban planning process are significant. Accurate analysis and synthesis enable to determine proper site selection and the proper site selection is the basis of a sustainable urban plan. In this sense, fundamental analysis inputs of the proper site selection could be indicated as the related parameters of the earth sciences. The interpretation of these inputs require the essential analyses and syntheses of initially the geological and geotechnical research with geophysics, tectonic, topography, mineral and natural resources, hydrogeology, geomorphology and engineering geology. Synthesis maps composed of these inputs especially provide guides for natural thresholds consisting of landslide, flood, inundation, earthquake etc. for land use planning and site selection parts in the urban planning processes. In this regard, this chapter of the book contains the relation between the earth sciences parameters with the urban planning and the way these parameters lead the way of urban planning processes.