## 1 Introduction  
Geotechnical investigation is considered to be a pre-requisite for any civil engineering project. It ensures the safe execution of the project and improves its feasibility, planning, and design phases. There is an increasing challenge for geotechnical engineers to quantify ground properties by considering potential variability between the sampling points. To assess the variability of soil properties at a site, it is essential to consider the correlation structure of soil properties. This study was meant to be an aid by providing an electronic geodatabase and ready-to-use geotechnical map for an economical preliminary investigation. This approach may reduce the cost and time required for such investigations and provides reasonable accuracy. A comparable work has been carried out in the field of topography, digital elevation modeling, and agriculture soil mapping. Geological, crop health, and precipitation mapping are also of interest to the researchers. However, in the literature, there are no significant contributions to the appraisal of geotechnical mapping. Engineering soil classification is not only important for preliminary recommendations on the feasibility of proposed projects but also plays a vital role while selecting identified material sources for the proposed projects. The American Association of State Highways and Transportation Official (AASHTO) classifies soils on the basis of their relative suitability as a subgrade material, which ranges from excellent to poor (A-1-A-7, in descending order). This rating considerably affects the selection of routes and alignment of motorways and highways. In addition, subgrade rating greatly affects the cost of these megaprojects. Subgrade rating can even lead to the selection or rejection of a particular route for the proposed highway. In addition, it can identify potential problems on a specific route. The well-developed maps containing information on engineering classification and subgrade rating can serve as an excellent tool for engineering planers. The generation of such maps requires an extensive exposure to soil formation, geological processes, topographic features, field exploration, and laboratory testing along with a reliable data analysis, interpretive and mapping tools. Thus, a desk study was performed, which evaluated the available topographic, administrative, and precipitation data, location, and route of water bodies in the area. In total, 75 locations were selected for drilling and collection of samples to determine requisite properties to be incorporated into the proposed geotechnical map. Reconnaissance survey was conducted on the sites chosen to acquire initial information about ground condition, e.g. visual soil classification, observation of geological features through examination of outcrops, tentative water table, suitable equipment for drilling at each site, equipment access to the selected site, nature of nearby water bodies if any, and social and cultural issues of the area. The reconnaissance outcome was systematically compiled. Finally, the exact location of 75 sites was selected for boring and collection of samples in a mesh grip pattern scattered throughout the geotechnically diversified plateau spread over an area of approximately 23,000 km\({}^{2}\). In total, 450 soil samples were collected from 75 data stations to determine requisite index properties and to be used for subsequent engineering evaluations. Laboratory tests were performed according to relevant American Society for Testing and Materials (ASTM) standards, and the results were compiled to create a database for further processing. ArcGIS is an emerging software for the analysis of datasets. It consists of diversified techniques for the interpretation, analysis, interpolation, and extrapolation of parameters. The test results were converted to form a geodatabase and uploaded to the ArcMap software.