PRACTICAL GEOGRAPHY

FIELD-WORK IN GEOGRAPHY

Field-work in geography involves the work of gathering information by going into the field to gain practical experience and knowledge through firsthand observation.   Stages of Field-work The execution of any field-work in geography may be grouped into three stages, viz. (a) The Pre-Field Stage This stage involves the following steps: • State the type of study (i.e. physical features, settlement pattern, land use pattern, agricultural products, provision of social services, transport system, etc in a particular settlement). • Design and get the appropriate questionnaire for the study area, if necessary. • Where and when you are conducting the study. • Assemble the materials you need to conduct the study. • The personnel to be involved in the fieldwork should be properly briefed. • The cost of the study should be well estimated. • Proper knowledge of the weather condition is essential in order to choose a favourable time when any disturbance like rain can be avoided. • The head of the team conducting the study with at least one member of the study team should make a pilot survey of the area of study before the actual field-work.   (b) The Actual Field Stage This is the stage where the actual field-work has to be carried out.   (c) Post-Field Stage All participants in the actual field-work will return to base in order to assemble, analyse and present what they had done during the field-work.

Posted in PRACTICAL GEOGRAPHY | Tagged , , | Comments Off on FIELD-WORK IN GEOGRAPHY

INTRODUCTION TO LAND SURVEYING

A Brief Historical Account: It is not yet specifically known where surveying originated, but it is very probable that it has its origin in ancient Egypt. For instance a plan of the villa of a great Egyptian noble was found in a Thebian tomb of the eighth century dynasty. In the tomb of one Menna, at Thebes, there is a representation on the walls of two chainmen surveying a field of corn, and in Ptolemaic and Roman Papyri in the same country, measurements of plots of land are described. The invention of printing and engraving in Europe in the fifteenth century and the age of discoveries which followed contributed much to the expansion of surveying and mapping activities.   Definition: Surveying is the science which has to do with the determination of the relative positions or locations of points on the earth’s surface. This involves the act of measuring horizontal and vertical distances and of determining direction and angular relationships by the use of surveying instruments in the field. Information from surveying is generally depicted graphically in the form of maps and charts. Since maps are regarded as the tools of geographers, it is imperative therefore for geographers to know the methods by which maps are produced. Classification: Surveying can be classified on two main bases. First, on the basis of the instruments used as in case of compass surveying, chain surveying, plane table surveying, photogrammetric surveying and trigonometric surveying. Second, on the basis of the function of the surveying as in case of topographic surveying, hydrographic surveying, route surveying, etc. Operation: The operation of any surveying can be classified into three phases, viz. (a) Pre-Field Operation • State the type of surveying. • State where and when you are conducting the surveying. • Assemble the instruments. • The personnel to be involved in the fieldwork must be properly briefed. • Proper knowledge of weather condition is essential in order to choose a favourable time when any disturbance like rain can be avoided. (b) The Actual Field Operation This is the phase where the actual field-work has to be carried out. (c) Post-Field Operation All the people involved in the actual field operation will now return to the laboratory with a view to making diagrammatic representation of what had been done on the field.   Chain Surveying and Chain Surveying Instruments Chain surveying is a particular method of surveying in which no angles are measured, only linear measurements are taken in the field. Chain surveying is usually used in fairly open ground. Chain surveying method is used in towns, areas and on development projects. It is a very useful method to the farmer who is surveying the area of his farm, but it is not suitable to adopt in a built-up or heavily-wooded area. Where visibility is obstructed along straight lines, chain surveying is impossible.   The Instruments • The Chain: This is of two types – Engineers chain which is about 50 metres long and the Gunter’s chain which is about 30 metres long. The chain is made of steel wire, and consists of long links joined by shorter links. It is accurate enough to measure the chain lines and offsets of small surveys. • Tape Measure: Tapes are used where greater accuracy of measurement is required, such as setting out of roads. They are marked in metres, centimetres and millimetres. They are usually 15 or 30 metres long, and are of different types. • Station Pegs: These are made of wood or iron. They are about 32.5 cm long. They have pointed markers which can be stuck into the ground. They are used to mark the stations. • Ranging Poles: They are made of wood or tubular steel and are usually 2 m long. They are painted in alternate bands of red and white, the bands generally being 0.5 m deep so that the pole may be used for measuring offsets. • Cross Staff: This is used to set out lines at right angles to the main chain line. • Optical Square: This instrument is used for similar purposes to the cross-staff, but it is easier to use and of greater accuracy.   (a) Why Chain Surveying is the Best for Beginners • It is the best because of its simplicity. • Many of its principles may be applied also to the other methods. • The apparatus is cheap or alternatively readily improvised and can be used with complete accuracy. • No advanced mathematical knowledge is required in this method. • Apart from the portability of the instruments, the method is relatively more accurate than other methods. • The method does not cost so much in terms of personnel and techniques.   (b) Procedure in Making a Chain Surveying • Reconnaissance: Walk over the area to be surveyed and note the general layout, the position of features and the shape of the area. If the preliminary inspection is thoroughly carried out, the actual surveying is thus made easier. • During the preliminary inspection, choose the main triangle. It is upon this that much depends and there must be plenty of time for consideration. • Build up the secondary lines of the surveying framework, starting from the main triangle, and remembering that all points must be fixed by intersection or measuring along the side of triangle or that side produced. • Take the chance to get an idea of the maximum dimensions of the surveying, by rough tape measurements or by pacing. This is useful when considering the scale. • Make a key diagram of the lines you are going to use, lettering or numbering the stations, and possibly sketching in one feature to help identification.   (c) Possible Errors in Chaining During a chain surveying exercise, it is possible to make anyone or some of the following mistakes: • Omitting to book one or more chain lengths. • Confusing tallies. • Miscounting the links. • Mistaking 9 m for 6 m on the tape. • Incorrect marking of the chain end. • Incorrect booking. • Mistaking dimensions when called out.   (d) Measurement of Offsets During the field-operation of a chain surveying, it is possible to discover that the outside boundaries of the area to be surveyed consist of curving hedges whose positions must be fixed by taking offsets; that is, to measure the perpendicular distances to the particular boundary at intervals from the chain line. Right angles are determined by using the optical square or crossstaff described above. The measurement of offsets is of vital significance to any survey because by so doing one is able to get the actual configuration of the area to be surveyed. This is why the surveyor has to ensure that enough offsets are taken whenever he is on the field to conduct a chain surveying or even a compass surveying.   (e) Booking During any survey, all measurements should be carefully entered in the field book. The field book must be portable. To make the field book, an exercise book may be used, whereby two lines measuring 2 cm apart down the centre of the page may be ruled. Nothing should be written between the lines except the distances along the chain line. Generally, booking starts from the bottom of the page and as one goes along the chain line, one works upwards: right and left on the page that correspond to right and left on the ground. The position of any building such as the shed in Figure 1.49 is fixed by making two measurements towards each of the nearer corners which can then be plotted accurately by intersecting arcs. The shed is then measured and plotted in order that the corners in question may fit the points which are already obtained.   (f) Chaining Round Obstacles During a chain survey exercise, it might be possible for the surveyor to come across some obstacles. To any advanced level student, chaining round such obstacles should not pose any serious problem. Two types of obstacles a surveyor may come across during a chain surveying exercise are discussed below: First, he may come across an obstacle across which he can see, e.g. a pond. The procedure for chaining round the pond may be in either of the two ways below: To measure the distance BC, range AB through to C. Line through B to any convenient point D, that clears the pond. With a pole at D range in E, making DE = BD. Produce CD to F in such a way that DF CD. FE is parallel to AC. Therefore, <EFD = <BCD (alternate angles. Similarly, <DBC = <DEF (alternate angles) <EDF = <BDC (vertically opposite angles). Therefore, it can be rightly concluded that triangle BDC = triangle FDE. By identical triangles FE = BC. The second way of chaining round the pond is by sticking in poles or arrows exactly on the line at A and B, then set out equal perpendiculars AC, BD, long enough to clear the pond. Then CD will be equal to AB and measurement along it can proceed as though it were in fact AB. Apart from the aforesaid, the surveyor may come across an obstacle through which he cannot see, e.g. a building. Let A and B be two points on the line approaching the building. Therefore, • set out equal perpendiculars BC, AD; • focus along CD and fix two other points, E and F, exactly in line with it beyond the building; • from E and F, set out perpendiculars EH and FG both equal to BC in such a way that G and H are in line with AB, and CE equals BH.   (a) Description of the Prismatic Compass It is a circular magnetic compass which has, on one side a prism, with a slit in it, and on the opposite side a sight vane, with a vertical hair. The plane containing the prism slit and sight vane hair also contains the pivot of the compass card, the central point of the compass. The prism reflects the figures of the card immediately below it and enables the surveyor to read the bearing without taking his eye from the sights and theobjects being sighted. There are several types of prismatic compass, but all areusedinmuch the same way. The cheapest and simplest to use and standing up best to hard-wear is the ordinary ‘service’ pattern as used in the army. The compass is light and easy to carry. Bearings can be taken much more quickly than with the theodolite. It eliminates the need for check lines and so forms a means of rapid survey. In spite of these advantages, the compass is not without its disadvantages. For instance, the degree of its accuracy is not high, and the instrument readings can be affected by ‘local attractions’. Rules Guiding the Use of a Prismatic Compass • In using a prismatic compass, it is imperative to bear in mind the following rules: • All magnetic materials should be removed from the pockets before the bearing is taken. • The bearing should not be observed from a position close to strongly magnetic material such as corrugated iron shed or railway. • The compass must be held horizontally so that the edge of the card does not rub against the top of the compass. • To accord with the surveying principle of independent checks, the ‘back’ bearing should be taken from the other end of the line, and should differ from the ‘forward’ bearing by exactly 180?. On the other hand, if the forward bearing is below 1800, add 180?. This principle applies to both the magnetic and true bearings.   (c) Reading the Prismatic Compass In reading the prismatic compass, efforts should be made to follow the undermentioned steps: • Raise the lid and move the prism over the card. • Pass the thumb through and use thumb and forefinger together to make a ‘platform’ on which the compass can be held level and steady. •…

Posted in PRACTICAL GEOGRAPHY | Tagged , , | Comments Off on INTRODUCTION TO LAND SURVEYING

COLONIAL RULE IN WEST AFRICA

The European scramble for Africa culminated in the Berlin West African Conference of 1884-85. The conference was called by German Chancellor Bismarck and would set up the parameters for the eventual partition of Africa. European nations were summoned to discuss issues of free navigation along the Niger and Congo rivers and to settle new claims to African coasts. In the end, the European powers signed The Berlin Act (Treaty). This treaty set up rules for European occupation of African territories. The treaty stated that any European claim to any part of Africa, would only be recognized if it was effectively occupied. The Berlin Conference therefore set the stage for the eventual European military invasion and conquest of African continent. With the exception of Ethiopia and Liberia, the entire continent came under European colonial rule. The major colonial powers were Britain, France, Germany, Belgium, and Portugal. The story of West Africa after the Berlin Conference revolves around 5 major themes: the establishment of European colonies, the consolidation of political authority, the development of the colonies through forced labor, the cultural and economic transformation of West Africa, and West African Resistance.   European Penetration and West African Resistance to Penetration Effective Occupation was a clause in the Berlin Treaty which gave Europe a blank check to use military force to occupy West African territories. 1885-1914 were the years of European conquest and amalgamations of pre-colonial states and societies into new states. European imperialists continued to pursue their earlier treaty making processes whereby West African territories became European protectorates. Protectorates were a loaded pause before the eventual European military occupation of West Africa. Because protectorate treaties posed serious challenges to West African independence most West African rulers naturally rejected them. West African rulers adopted numerous strategies to forestall European occupation including: recourse to diplomacy, alliance, and when all else failed, military confrontation.   Recourse to Diplomacy The British found few people as difficult to subdue as the Asante of Ghana in their quest to build their West African colonial empire. The Asante Wars against the British, which began in 1805, lasted a hundred years. Although outmatched by superior weaponry, the Asante kept the British army at bay for a short final period of independence. To understand the Asante wars, one has to look at role of King Prempeh I, who firmly resolved not to submit to British protection. When pressured in 1891 to sign a protection treaty which implied British control of Asante, Prempeh firmly and confidently rejected idea. Here are his words to the British envoy: The suggestion that Asante in its present state should come and enjoy the protection of Her Majesty the Queen and Empress of India, is a matter of very serious consideration and I am happy to say we have arrived at this conclusion, that my kingdom of Asante will never commit itself to any such policy. Asante must remain [independent] of old . . . In 1897, King Prempeh was exiled, and the Asante were told that he would never be returned. He was first taken to Elmina Castle. From there, he was taken to the Seychelles Islands. In 1899, in a further attempt to humiliate the Asante people, the British sent British governor Sir Frederick Hodgson to Kumasi to demand the Golden Stool. The Golden Stool was a symbol of Asante unity. In the face of this insult the chiefs held a secret meeting at Kumasi. Yaa Asantewa, the Queen Mother of Ejisu, was at the meeting. The chiefs were discussing how they could make war on the white men and force them to bring back the Asantehene. Yaa Asantewa saw that some of the bravest male members of nation were cowed. In her now famous challenge, Yaa Asantewa declared: How can a proud and brave people like the Asante sit back and look while white men took away their king and chiefs and humiliate them with a demand for the Golden Stool. The Golden Stool only means money to the white man; they searched and dug everywhere for it . . . If you, the chiefs of Asante, are going to behave like cowards and not fight, you should exchange your loincloths for my undergarments. That was the beginning of the Yaa Asantewa War. The final battle began on September 30, 1900, and ended in the bloody defeat of the Asante. Yaa Asantewa was the last to be captured, and subsequently exiled to the Seychelles, where she died around 1921. With the end of these wars, the British gained control of the hinterland of Ghana. Around the same time, Behanzin, the last king of Dahomey (1889-94), told the European envoy that came to see him: God has created Black and White, each to inherit its designated territory. The White man is concerned with commerce and the Black man must trade with the White. Let the Blacks do no harm to the Whites and in the same way the Whites must do not harm to the blacks. In 1895, Wobogo, the Moro Nabaor king of the Mossi told French Captain Restenave: I know the whites wish to kill me in order to take my country, and yet you claim that they will help me to organize my country. But I find my country good just as it is. I have no need of them. I know what is necessary for me and what I want: I have my own merchants: also, consider yourself fortunate that I do not order your head to be cut off. Go away now, and above all, never come back.   Alliance When West African leaders struck alliances with the imperialists, they did so in an attempt to enhance their commercial and diplomatic advantages. King Jaja of Opobo, for instance, resorted to diplomacy as means of resistance to European intrusive imperialism. Mbanaso Ozurumba, a.k.a Jaja was a former slave of Igbo origin. He was elected as king of the Anna Pepple House in Bonny, Niger Delta, in 1863, following the death of his master. Soon a struggle between the Anna Pepple House and Manilla Pepple House led to the outbreak of civil war in Bonny in 1869. The war resulted in King Jaja’s migration and founding of the inland kingdom of Opobo which lay in the palm oil producing hinterland. Jaja was an avowed nationalist and determined to control the trade in his political domain. He was determined to prevent European incursions into the interior. He also wanted to ensure that Opobo oil markets remained outside the sphere of foreign traders. To this end, King Jaja signed a trade treaty with the British in 1873. Part of the treaty reads as follows: After April 2, 1873, the king of Opobo shall allow no trade established or hulk in or off Opobo Town, or any trading vessels to come higher up the river than the Whiteman’s beach opposite Hippopotamus Creek. If any trading ship or steamer proceeds further up the river than the creek above mentioned, after having been fully warned to the contrary, the said trading ship or steamer may be seized by King Jaja and detained until a fine of 100 puncheon [of palm oil] be paid by the owners to king Jaja . . . By signing the treaty, the British acknowledged Jaja as the king of Opobo and dominant middleman in the Niger Delta trade. However, the ensuing scramble for Africa of 1880s upset the understanding. The British merchants and officials were no longer in the mood to respect Jaja’s preeminence in the Niger Delta hinterland. They instead penetrated the hinterland to open up free trade and therefore a confrontation with Jaja became inevitable. In 1887, the British consul Harry Johnson enticed Jaja to the British gunboat for discussions; but then exiled him to West Indies where he died in 1891.   Military Confrontation Some decentralized West African societies equally resisted European penetration. The Baule of Ivory Coast and Tiv of Nigeria stiffly resisted colonial occupation. The Baule fought the French from 1891-1911. The Tiv fought the British from 1900-30; and Igbo resistance was particularly widespread and prolonged. Because of the egalitarian nature of their society, the British found it extremely difficult to subjugate them. The British literally had to fight their way from Igbo village to village, from town to town, before they could finally declare their imperial authority over the Igbo people. Igbo elders challenged the British imperial penetration and invited the British to: “Come and fight: if you want warm, come, we are ready.” The British waged wars from about 1898-1910. While West Africans fought gallantly against their European intruders; everywhere but Ethiopia, the Europeans were triumphant.   European Political Policies in their West African Dominions  The British in West Africa  The 19th century British colonial policy in West Africa was a policy of assimilation. Their grand plan was to have Africans assimilate into European civilization and culture.  The policy created a western class of black Englishmen who were supposedly British partners in religion, trade and administration.  These African “British men,” especially Creoles, rose in colonies of Freetown, Bathurst, southern Ghana and Lagos to important positions in the church, commercial firms and the colonial government.  However, with the growth of European racism, western educated Africans (elites) found that they were increasingly discriminated against in administration. The British now imported European administrators to fill positions previously held by Africans.  Western educated Africans like the Creoles were even forced out of the civil service. In 1910, the British colonial office expressed the opinion that Englishmen naturally expected to enjoy fruits of their conquests, therefore they should be preferred over Africans in senior positions. The problem however was that there were not enough Englishmen prepared to serve as colonial administrators in Africa.  Therefore, the British soon adopted the policy of Indirect Rule. Indirect Rule was the brain child of Lord Lugard. He presented the principles of the system in his book The Dual Mandate in Tropical Africa. In it, he identified the two most important administrative principles to employ in ruling alien people. The first was the principle of decentralization, in which he stressed importance of recognizing and ruling people through their indigenous authorities.  He argued that the role of the British officers, except in critical areas such as taxation, military forces and the alienation of land, was to advise, not demand. The second principle, was the principle of continuity. Lugard argued that the British should utilize indigenous institutions and authorities, thereby preserving “continuity” with the past, while laying foundations for what he saw as the progressive improvement of indigenous society. Indirect Rule which begun as administrative expedient in Northern Nigeria, would eventually be imposed throughout their territories of British Africa.   Administrative Policies The British set up separate administrative machines for each of their colonies.  At the head of each colony was the governor, who was responsible to the Secretary of State at the colonial office. He administered the colony with assistance of a partly nominated legislative council and executive council of officials.  Most of the laws of the colony were drawn up by the government or his council. Each colony was divided into regions under a regional or chief administrator.  The regions were divided into provinces which were controlled by the provincial commissioners.  Each province was divided into districts under leadership of a district commissioner.  Each district was divided into one or more traditional states which were ruled by traditional rulers.   Features of Indirect Rule Indirect Rule saw to the mapping out of relatively large areas which were subject to single authority: Smaller ethnic groups were included in the jurisdiction of their larger, more highly organized neighbors. And district heads, especially in Igbo and Ibibiolands, Nigeria, were appointed to defined areas without much consideration to their relationship with the populations under their authority. Indirect Rule sustained tyrannical and corrupt governments and promoted divisions in populations: In Northern Nigeria, the system strengthened the emirates, therefore increasing the possibility of revolution by the oppressed peasantry.  In Igboland and Ibibiolands, warrant…

Posted in DIPLOMATIC HISTORY, PRACTICAL GEOGRAPHY | Tagged , , , | Comments Off on COLONIAL RULE IN WEST AFRICA

COMPONENTS OF GEOGRAPHIC INFORMATION SYSTEM (GIS)

A working GIS integrates these five key components: hardware, software, data, people and methods. Hardware: Hardware is the computer on which a GIS operates. Today, GIS runs on a wide range of hardware types, from centralized computer servers to desktop computers used in stand-alone or networked configurations. Software: GIS software provides the functions and tools needed to store, analyze and display geographic information. Key software components are: A database management system (DBMS). Tools for the input and manipulation of geographic information. Tools that support geographic query, analysis and visualization. A Graphical User Interface (GUI) for easy access to tools. Data: Maybe the most important component of a GIS is the data. Geographic data and related tabular data can be collected in-house or bought from a commercial data provider. Most GIS employ a DBMS to create and maintain a database to help organize and manage data. People: GIS technology is of limited value without the people who manage the system and to develop plans for applying it. GIS users range from technical specialists who design and maintain the system to those who use it to help them do their everyday work. Methods: A successful GIS operates according to a well-designed plan and business rules, which are the models and operating practices unique to each organization.   FUNCTIONS OF THE MAJOR HARDWARE COMPONENTS IN A COMPUTER SYSTEM The main function of a computer system is to process information. An example, operation done using a computer is to create a document. The processing of this information goes through a set of phases, each of these phases require its own set of devices. The first phase is the input phase, where data is entered into the computer system through input devices. After data is inputted into the computer system, it is then processed and some changes or computations are done by the Central Processing Unit (CPU). During the time which the document is being modified, the document needs to be stored temporarily in the computer’s main memory for the CPU to access it. To save the document for future use, it is stored in secondary storage. The document is then outputted to the screen or printed.   MAJOR HARDWARE COMPONENTS The major hardware components of a computer can be broadly categorized as: CPU (CU, ALU). Main Memory/Immediate Access storage (primary storage). Secondary storage. Input/output devices.   CPU: The Central Processing Unit (CPU) is the brain of a computer system. It carries out the instructions of a computer program, to perform the basic arithmetical, logical and input/output operations of the system. The CPU is made up of the Control Unit (CU) and the Arithmetic and Logic Unit (ALU). CU: The control unit is part of the CPU that instructs other parts of the computer system to carry out program instructions. ALU: The ALU is a digital circuit that performs arithmetic and logical operations. Main Memory: Main memory is a form of Immediate Access Storage also known as primary storage, it is volatile memory directly accessible to the CPU and is used to store data actively operated on. The CPU continuously reads instructions stored there and executes them as required. Information stored in main memory is lost when the computer is powered off. Secondary Storage: Secondary storage differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the desired data using an intermediate area in primary storage. Secondary storage does not lose the data when the device is powered off and it is non-volatile. Secondary storage devices include the Hard Drive, Flash Drive, and Memory Card. Input Devices: An input device is any peripheral (piece of computer hardware equipment) used to provide data to the computer. Input devices include the Mouse, Keyboard, Touch Screen Monitor, Scanner, Track Pad, Microphone, Joystick, and Web Camera. Output devices: An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by the computer to the outside world. Output device include the Speaker, Printer, Monitor, Plotter.   THE SOFTWARE COMPONENTS AND THEIR USES System Software: System software sits directly on top of your computer’s hardware components (also referred to as its bare metal). It includes the range of software you would install to your system that enables it to function. This includes the operating system, drivers for your hardware devices, linkers and debuggers. System software can also be used for managing computer resources. System software is designed to be used by the computer system itself, not human users. Application Software: Unlike systems software, applications designed to use by end-users. Application software, in essence, sits on top of system software, as it is unable to run without the operating system and other utilities. Application software include things like database programs, word processors and spreadsheets, e-mail applications, computer games, graphics programs and such. Generally, people will refer to application software as software.   TYPES OF APPLICATION SOFTWARE The Growing List of “Ware” Terminology Today we find new terms created frequently to classify types of applications software. You have classifications based on usage. For example, games or financial software, office applications and other categories where the category is derived based on the main use of the software. Unfortunately, we also have a newer group of software related terms that have a negative association. While the application software itself may be useful, it may also carry hidden programs or utilities that may cause undesirable effects.   DISTINGUISH BETWEEN POSITIONAL AND RELATIONAL DATA Position Data: Refers to data that identifies the precise location of the device that collect geospatial data. Relational Data: Relational data consist of data that a result from a connection. Relational data is a jointly owned property among the actors as a result of their association. Some examples of relational data are: Kinship, friendship, boss/subordinate, project team membership and group association.   STATE THE PROCEDURES OR RULES FOR GIS The GIS procedure creates and maintains the spatial databases that are used by SAS/GIS software. A SAS/GIS spatial database consists of the following elements: SAS data sets that contain the coordinates and identifying information for the spatial features. A spatial entry (a SAS catalog entry of type GISSPA) that identifies which SAS data sets contain spatial information. The spatial entry also stores the following elements: Composites that define how the variables in the spatial data are used. Names of the polygonal indexes that define the boundaries of area layers for the map. A lattice hierarchy that defines which features in the spatial data enclose or are enclosed by other features (the relationships among the polygonal variables). Information about the projection method that is used for the stored spatial data.   A spatial entry alternatively can contain references to two or more other spatial entries that have been merged into a single spatial database. A coverage entry (a SAS catalog entry of type GISCOVER) that selects a subset of the spatial data that is available for display in a map. One or more layer entries (SAS catalog entries of type GISLAYER) that identify features that have common characteristics and specify how they are displayed as layers in the map. © a map entry (a SAS catalog entry of type GISMAP) that specifies which layers from a particular coverage are included in a map. The map entry also stores the following information: The names of attribute data sets that are associated with the map, along with definitions of how the attribute data is linked to the spatial data. The name of a SAS data set that contains labels for map features. Definitions of GIS actions that can be performed when map features are selected. Definitions for map legends. Values for display and projection options.   Graduate Registration: To register as a graduate for this scheme, you must: Be a citizen of Nigeria (must provide a valid ID). Be between ages 18 – 40 years (must provide birth certificate). Have completed the mandatory NYSC or exempted. Be holder of a degree equivalent (e.g. BSc, BEng, BA and HND) certificate or higher qualification. Have a recent passport type photo ready to be uploaded during online registration. Please note; size of image must not exceed 99kb. Complete the online registration form. Make available all original documents for sighting at point of selection.   Employer Registration: To register as an employer for this scheme, you must: Be registered with Corporate Affairs Commission (CAC) and other relevant professional bodies. Provide evidence of VAT registration and the latest Tax Clearance Certificate. Prove that they are economically viable and engaged in legitimate business by providing other relevant documents e.g. Company profile and audited accounts. This information will be used to examine the firm’s progression since its inception. Be prepared to provide a mentoring plan for each intern. Be prepared with specific assignments for interns. Be able to employ interns for a period of one (1) year. Companies with outstanding tax issues or where the owners or directors have convictions for fraud will not be eligible to register for the programme.   Internship Position Posting: Intern positions posted must. Be legitimate positions available on the stated timescale. Be suitable work for a Graduate. Not require the Graduate to undertake work that is illegal or unsafe. Meet standard safety regulations/facilities. Be able to provide at least 12 months of skills development. Be able to provide a mentoring plan to guide skills development.   Applying for Work: When applying for positions as a Graduate you must. Be available to work at the chosen business and location. Be willing to undertake a full 12 month placement. Be prepared to comply with the employer’s safety and employment practices.   Payment of Interns Payment of Intern will be undertaken directly by the PW/WYE PIU to the Graduate intern. Neither the Graduate nor the employer are required to pay any fee for using the Graduate intern scheme service, and no fees, charges or commissions are to be paid to any party in relation to this scheme by the Graduate or the Employer.   IDENTIFY GIS HUMANWARE Humanware is hardware and software that emphasizes user capability and empowerment and the design of the user interface. The process of building humanware generally consists of these steps: Define users (age, mindset, environment context, previous product experience expectations, and so forth) and what they really want to do. Identify tasks they will need to do or capabilities they will want. Specify usability objectives (if possible, these should be measurable, such as how long to do something or how many mouse clicks to get to a specified task point) for each task or capability. Build a prototype of the user interface (it can be a paper or stimulated prototype if the time is short). Test and verify or correct the prototype. Provide the prototype and usability objectives to the program designers and coders. Test the code against the prototype and objectives and, if necessary, redesign or recode the software. Test the product with users or valid test subjects and revise as necessary. Get feedback from users and continually improve the product. Philips Research uses the term for both software and hardware that is specially designed to interact with users, including its speech synthesis and speech recognition microchips.

Posted in PRACTICAL GEOGRAPHY | Tagged , , , | Comments Off on COMPONENTS OF GEOGRAPHIC INFORMATION SYSTEM (GIS)

GEOGRAPHIC INFORMATION SYSTEM DATA

Data input refers to the procedure of automatization of the data and the conversion into forms that can be stored and analyzed in computers. This procedure is fundamental in every GIS and it differentiates depending on the model (vector or raster) and the origin of the data.   SOURCES OF GIS DATA There are many sources of data available for Geographical Information System (GIS). Such sources include the following: Land surveying. Remote sensing. Map digitizing. Map scanning. Field investigation. Tabular data.   Land Surveying: Land surveying is defined as the process by which measurement of land is made and then represent such measurement by tables, plans or layout for specific purposes. It can also mean the measuring and mapping out of the position, size and boundaries of an area of land. Remote Sensing: Remote consists of the main sources of digital data for input in a GIS. Remote Sensing (RS) provide useful tools for environmental and natural resources management. They are widely recognized as supporting and management of the appropriate utilization of resources at the country, regional and global levels. Through the use of remote sensing, employment opportunities are available in a wide range of areas; including agriculture, forestry, coastal development and management, urban planning and development, medical technology, mapping and planning, disaster mitigation and environmental management. Map Digitizing: Map digitizing involves the extraction of data values from graph e.g. in most scientific publication only plots but no data values are published. Map digitizing involves a three step process: Import the graph from a file or copy it over the clipboard. Define the axes system. Digitize it automatically or manually. Map Scanning: Another commonly used method for data input is scanning. Existing maps of various scales containing different type of information about the area of interest in small or big detail. These maps can be scanned, thus the information of these maps can be fed into a GIS and be integrated with other existing information. Field Investigation: During public health emergencies, such as bio terrorist attacks and disease epidemics, computerized information systems for data management, analysis and communication may be needed within hours of beginning the investigation. Available sources of data and output requirement of the system may be changed frequently during the course of investigation. Written documents; guidelines and memos important to the epidemics were frequently revised. In this investigation, a database was operational on the second day and the GIS component during the second week of the investigation. Tabular Data: This is another type of data commonly used in Geographical Information System (GIS). It involves the use of special data arranged in tables and such data are analyzed and process by computer in order to generate useful information that are relevant to the Geographic Information System.

Posted in PRACTICAL GEOGRAPHY | Tagged , , , | Comments Off on GEOGRAPHIC INFORMATION SYSTEM DATA
error: Content is protected !!