A REPORT ON AN INTERNSHIP WITH GEOLOGICAL SURVEY DEPARTMENT; GIS LABORATORY. ACCRA, GHANA.
From 5th June 2017 to 7th July 2017, I did an internship with geological survey department. This internship was part of a semester course; Introduction to geographic information system taken in the University of Ghana, Legon. The main objective of this internship was to enable students to practice what they have been taught in a professional working environment.
The geological survey department was founded in 1913 and at the moment works under the Ministry of Lands and natural resources. The department is the repository of the country’s geosciences database, it is known to generate, collect, store and archive relevant geoscientific data and give out this information to the government, industries and the public at large. It is therefore responsible for the country’s mineral resource potential studies.
The geological survey department as a principal curator of national geoscientific data, has the main task to continuously generate, collect, store and archive relevant geoscientific data, to disseminate data and information in user-friendly way to the government, industry and the public at large. Generation of geoscientific data is done in field surveys, research and investigations. The department has the responsibility to advise the Nation to make informed decision on geoscientific issues concerning mineral and groundwater resources, environment, geohazards and land use planning Vision.
The Geological Department aspires to be an internationally recognized organization contributing to the developmental agenda of the country through the provision of geoscientist information.
The department is divided into various divisions such as the geological mapping division, the geochemistry and laboratory services division, economic geology division, geophysics and information management division, the environmental and geology division, the seismology and earthquake engineering division and lastly the ceramics and clay mineralogy division. However, it is under the Geophysics and Information Management Division that the GIS lab can be found.
All interns were briefed on what the department was about and how things are to be expected in the subsequent weeks. We were taken to the GIS lab first to introduce us to our supervisors. Later to the museum to study the Geology of Ghana. We were then moved to the drawing room to study about maps and coordinates. All these were done within the first week. The second and following weeks were then spent in the GIS Lab where we were taken through a series of various GIS procedures. Aside the ArcGIS software, other software used here includes map info.
Before work is done in the lab, field work is firs done in order to get all the primary data such as the geographic coordinates which is taken with the GPS. A topo sheet is taken along to the field as well. A desk study is done to know if the place of interest has already been studied. After the field work, the data taken is ten brought to the GIS lab for analysis. Here, data is entered into the excel spreadsheet and filter the data. Filtering is necessary because there is a possibility some of the data have been entered twice.
I worked on a project which involved creating a geological map on Kwahu Mpaso. A map of field sheet 0601A3 was scanned. The main content of the project was to use the ArcGIS to turn the analog map into a full geological map. The various procedures that were involved in this project included: georeferencing, digitizing, projection and data integration. To begin with, the field sheet was scanned and loaded onto the ArcMAP, control points were taken and the map was georeferenced. After the image was georeferenced, it was projected to the WGS_1984_UTM_Zone_30N under the geographic coordinate system. Once the map was projected it was easier and convenient to continue the latter processes. The next processs that was taken is digitizing. All the polygons within the map were all digitized and entered into the attribute table. After digitizing the image, the image was taken through symbology where the various polygons were represented by colours, here it is important to note that, the various features take the universal geological colours so as to help in easy identification.
From here, the image was set to be turned into a map. The view was therefore changed to layout view to start map creation. A title, a legend, grid lines, scale bar and scale text were all inserted into the map. The north arrow was also inserted into the map to give in more information. However, the map was incomplete; other features on the map had not yet been included. These features included the water bodies, transport systems and also transport. These information were not available at the geological survey department. As a result, a process called data integration was done. This is the process whereby information from sources and institutions are brought together to produce meaningful information for persons interested such as the government, private individuals and industries.
Information was taken from the Survey and Mapping Division of Lands Commission. This information contained all features on the field sheet 0601A3. However these files had to be exported from E00. A new ArcMap window was opened to be able to carefully select and work on the needed features. Here, the 0601A field sheet was clipped out of the entire Ghana map showing all the various grids. But since the main interest was in the 0601A3 it was necessary to clip only that one out of the entire 0601A sheet.
The features were then converted to shapefiles and then loaded onto the image. The features were however loaded on all the grids, it was therefore important to clip only those that all within the field sheet 0601A3. Here transport, water and forests were clipped onto the image. After all these some difficulties came up, this is because the clipped feature 01601A3 shifted from its original position. To fix this, both the clip feature and the original feature were projected in the same coordinate system. Unfortunately, the error was unable to rectify. As a result of this, the process called spatial adjustment to rectify the error. There 4 control points were taken just as it happens in georeferencing. After these control points were taken, set adjust data was selected and finally selected adjust. After this command, the clipped feature lied perfectly unto the original map. The data was saved so it can be loaded onto the map.
After all these, the grid is ready to be overlaid on the map that has created in the other ArcMap window. Here click on add data and select the saved work on the features. The next step from here was to make any final corrections and export the new geological map in ‘tiff’ format .
Lastly, sometime was spent at the drawing room and the museum. At the drawing room I was taken through the various features of a map and how a map is made. Learnt about the coordinates and scale and how to also calculate distances.
Consequently, at the museum I was taken through the geology of Ghana and the various mineralised rocks in the country. Ghana can conveniently be divided into five geological domains or provinces on the basis of age, tectonics and lithologic characteristics of the supracrustalrocks. These are:
(1)The western unit which lies at the eastern margin of the Precambrian West African Shield
(2) The southeastern unit which is at the southeastern part of the country belonging to the
Precambrian Mobile Belt and
(3) The flat lying central unit made up mainly of the sediments of the Voltaiansystem
(4) The coastal basins and
(5) Tertiary to Recent deposits
In Ghana the Birimian is sub divided into the Lower Birimian, which is dominated by metasediments, and Upper Birimian, which is dominated by greenstone-type metavolcanics. There are also the Tarkwanian group, the Eburnean plutonic suite, Kwahu Morago group, Oti-Pendjari group and the obosum group.
CHALLENGES AND CONSTRAINTS.
During my internship in geological survey department, I encountered a number of difficulties.
Some of the challenges include the following;
There were inadequate resources and machines such as computers and printers to aid in the proper usage of skills acquired. The GIS/REMOTE SENSING internship program was meant to help students to improve upon their skills in a professional working environment. However, due to the unavailability of the necessary machines learning and working became difficult.
Lastly, another challenge faced was the unavailability of some staff members during some points in the internship. This made it difficult for interns to approach them when we had challenges.
In view of the above stated, I would humbly recommend that the laboratory be restocked with the necessary machines needed to enable interns to be able to learn and work efficiently.
Not only was I able to gain through this project and internship, I was also able to sharpen my skills in GIS in a professional working environment. I also had the opportunity to interact well with experts in the field of GIS/REMOTE SENSING. Consequently through this internship I was given the opportunity learn more about the geology of Ghana, geological maps and more importantly how geological data are collected. I appreciate the opportunity given by the Geological survey department to be able to work with them.
Much thanks to the director Dr Boamah and Deputy Director (technical); Dr Anum and most importantly to my supervisors who took me through this internship; Mr Jonas Bediako, Mrs Keren-Happuch Osekre and Ms Yvonne Marfoa Anokwa for their time and patience and the knowledge they impacted during my stay there.