After decades of using only one map projection, the Polyconic, for its mapping program, the U.S. Geological Survey (USGS) now uses several of the more common projections for its published maps. For larger scale maps, including topographic quadrangles and the State Base Map Series, conformal projections such as the Transverse Mercator and the Lambert Conformal Conic are used. Equal-area and equidistant projections appear in the National Atlas.

The map area, covering 2,250 km", lies in the central part of Spitsbergen, south of Isfjorden. Geological investigations were started by Swedish expeditions in the last half of the 19th century, and the work was continued in the present century mainly by Norwegian expeditions. The region is mountainous, moderately glaciated, but shows a juvenile glacial morphology. The climate is polar. The rock sequence exposed in the area is c. 3,400 m thick and consists of two Permian, six Mesozoic, and six Tertiary formations. The Permian deposits are mainly eherts , cherty limestones, limestones, and sandstones deposited under marine conditions. The Mesozoic-Tertiary sequence is composed generally of shales, siltstones, and sandstones deposited mainly in marine environments, and to a lesser extent under terrestrial conditions. Surficial deposits of Quaternary age are largely of glacial, colluvial, alluvial, and marine origin <...>

In various geosciences branches, including mineral exploration, geometallurgical characterization on established mining operations, and remote sensing, the regionalized input variables are spatially well-sampled across the domain of interest, limiting the scope of spatial uncertainty quantification procedures. In turn, response outcomes such as the mineral potential in a given region, mining throughput, metallurgical recovery, or in-situ estimations from remote satellite imagery, are usually modeled from a much-restricted subset of testing samples, collected at certain locations due to accessibility restrictions and the high acquisition costs.

Many Third World and developing countries rely mainly on the utilisation of their natural resources to sustain their economic development. In the Philippines in particular, the exploitation of mineral resources has traditionally been a significant component of the Philippine economy (Domingo, 1993).

Modelling and prediction of spatially distributed data such as the secondary cassiterite mineral distributions are often affected by spatial autocorrelation (SAC); a phenomenon that violates attributes data independence in space, which leads to type1 errors in classical statistics and overfitting or underfitting in machine learning (ML) classification respectively. The concept of overfitting and underfitting of spatially distributed datasets in an ML classification has not been properly addressed by the traditional random holdout technique of model validation, and this is a challenge to the assessment of predictive spatial model performance in spatially distributed datasets.

Geological maps represent the solid geology at the Earth’s surface unconcealed by vegetation, soil or buildings (figure 1a). Different rock types and formations are illustrated by different colours and/or symbols. Other features such as faults, mineral veins, coal seams, marker horizons and landslips are shown. Bedding and structural features such as cleavage and foliations are indicated by strike and dip or plunge and azimuth symbols (figure 1b).

The Hoggar, which forms the Algerian part of the Tuareg shield, is an ideal site for geoscientific studies. As the site of successive orogenies, it offers a single example of the problems that arise on a continental scale, whether in terms of magmatism, metamorphism, structure, metallogeny or geophysics.

Subsurface fluid flow is critically dependent on the 3D distribution of petrophysical properties in rocks. In sequences of sedimentary rocks these properties are strongly influenced by lithology and facies distribution that stem from the geologic processes that generated them.