*3.2.2 GIS and maps*

At the end of the planning phase, three types of resources related to the GIS are available i.e. physical maps, a raster map inside a GPS, and the GIS inside the PC. The GIS of the project should contain all the necessary maps for the team to work on the field. It consists of the information concerning basemaps, topographic maps, Digitital Terrain Model (DTM) or hill shade, hydrography, administrative units and planned points. ArcGIS software can easily store the GIS. Here some fields and maps can be activated or deactivated, in order to find additional information for the field team. The GIS is used to convert all the above maps into one raster in order to be manipulated in other systems. When converted, the maps are printed to obtain physical maps (**Figure 4**). The same maps can be sent into GPS for the navigation through Basecamp software.

The term basemap is seen often in GIS and refers to a collection of GIS data and or orthorectified imagery that form the background setting for a map. Satellite images can *DOI: http://dx.doi.org/10.5772/intechopen.106632 GIS and Database Management for Mining Exploration*

**Figure 4.** *Satellite image (SRTM) of the study area with 30 m of resolution.*

be collected from free verified available platforms like United States Geological Survey (USGS). They store geographical information, localization, and many others important features. The function of the basemap is to provide background detail necessary to orient the location of a map. Basemaps serve as a reference map on which you overlay data from layers and for geologists to be able visualizes geographic information.

The shaded relief is also used to highlight the forms of the relief and enhance the quality of the map (**Figure 5**). The hillshade function produces a gray scale 3D representation of the terrain surface, with the sun's relative position taken into account for shading the image. It is a technique for visualizing terrain determined by a light source and the slope and aspect of the elevation surface; this tool creates a shaded relief raster from a raster. The illumination source is considered to be at infinity. The hillshade raster has an integer value range of 0–255 m.

**Figure 6** shows hydrography map of the study area. It is a survey map which reveals the waterway system of the study area. The hydrographic pattern is dense with the main stream being the Lom River with the primary tributary being; mikila and several second order streams.

A topographic map is a detailed and accurate illustration of man-made and natural features on the ground such as roads, railways, power transmission lines, taken from the national institutions are put on the basemaps and used for geo-referencing and digitalization of roads and streams. Topographic maps are raster maps like basemaps. They store information related for topography information. Localization and streams are also a part of them (**Figure 7**). This help for digitalization.

Digitalized data are built by the GIS unit. The team digitalizes streams and roads mainly based on the basemap and the topographic map. The result here is a vector map. The objective is to have a digitalized feature as they are easy to manage than raster maps.

**Figure 5.** *Shaded relief of the zone derived from satellite image.*

**Figure 6.** *Hydrography of the study area derived from the satellite map.*

*DOI: http://dx.doi.org/10.5772/intechopen.106632 GIS and Database Management for Mining Exploration*

**Final Map**: Planned points are points to be sampled on the field. The streams to be sampled are a part of the norms established by the project's needs (**Figure 8**) we see that the Lom river is flowing following the NW° SE direction.
