This Chapter describes the need for GIS in general and for GILES in particular, their advantages in form of large data handling, quality, output, speed, updating, and how politicians and planners can make use of these advantages.
Ever-increasing population leads to pressures on the available resources of the land that exceed its carrying capacity. Resulting overutilization leads to resource degradation: Soil erosion, changes in flow regimes of rivers, changes in precipitation regimes due to deforestation, development of gullies, scarcity of fuelwood, to name only a few phenomena in Ethiopia. This results again in a stronger overutilization and worse degradation.
Effective land-use planning is necessary if this degradation of natural resources is to be stopped and optimal use to be made of the land for sustained and increased agricultural production to support the population.
This requires comprehensive information on land resources so that development strategies can be assessed in terms of all relevant environmental relations, such as climate, soil, land form, water etc. to define physical resources, but as well as of population, infrastructure, agricultural activity to define demand and activities. The generally accepted response to this process is the establishment of a management structure for natural resources.
The lack of adequate information, accessible to decision makers and planners, on which natural resources management is based has been identified as one of the reasons for - up to now - limited impact on the definition of appropriate land use plans and activities. It is in relation to this point that setup and development of information systems to support resource management had to be initialized.
Politicians, policy and decision makers, planners, supervisors, managers, development agencies require more and better resource information !
The need to match the land requirements for producing food and supporting populations to the resources of climate, soil, water, and available technology led to the assessment of the suitability of the land for agricultural purposes, a powerful - and essential - tool in the hand of decision makers and land use planners.
Thematic maps of earth resources prepared by the concerned specialist (soil scientists, climatologists, hydrologists, geologists, ecologists, land-use specialists) gave partly the answer for these questions. They have been - and are - a source of useful information for resources exploitation and management.
But the need for spatial data and spatial analysis has not been restricted only to earth scientists. Additionally to information about physical resources, decision makers need detailed information about the land and its rather economic and infrastructural characteristics.
In the past, data were collected and then documented in hardcopy format as tables or maps. Indeed, the rapidly increasing population and environmental changes result in a fast change of data and high need for fast, updated interpretation of those data. Formulation of essential actions and plans therefore require faster, more and better data than in the past to handle - and hopefully to solve - the problems of land degradation and population support.
But ultimate goal of resource monitoring must be to go one step further: to analyze not only the supply but also the demand and the accessibility of the resources.
a) In the past, examples abounded of data collection exercises that got stuck in their own abundance of data which at one side was necessary to assess the resources - and potential - of the land, on the other side could not be handled manually anymore. This need for handling large data quantities of the environment for rather detailed assessments can highly be met by a new technology developed in the past and applicable on a wide scale only in the past 10 years: The electronic processing of digital data by 'computer' !
The increasing capability and availability of computer and its technologies and experiences have a revolutionary effect upon the techniques available to those responsible for the assessment and management of natural resources. This development was encouraged by progressively cheaper, more user-friendly and better performing computer facilities.
Various attempts were made on a global basis as well as on national levels in different countries to develop and to install a computerized data base system of the resources inventory (CDC 1986; Nag 1987; Shupeng 1987; Bellamy 1986, to name only a few). Until now, much emphasis has been put on information systems as data bases providing facilities to store and retrieve these data.
b) It is not only the size of the data collected and interpreted, but often the prompt demand for information which can not be delivered rightly in the traditional, manual way. Most of the requests by land use planners, governments, implementation agencies etc. are in high urgencies. An important objective of a data-processing system is to provide a rapid and comprehensive response to ad hoc requests for data retrieval and interpretation.
Computerized storage encounters a wide range of available, immediate retrieval operations of the requested information - processed, modified , manipulated or raw, in the required way of presentation.
c) It is not only one subject which allows the definition - the need and the potential - of natural resources, but a number of parameters, being in a dependant interrelation with each other. One influences the other. These interactions are difficult to assess and were in the past the cause for misplanning, misinvestment and damage of the nature, even for many disasters caused by 'wrong planning', i.e. planning based on wrong information supplied by the resource data base which might not have considered the interactions.
The fact that the environmental data recorded by individual surveyors are stored and available in digital and computer compatible form from the very beginning enhances this possibility of allowing computers to complement man for an optimal use of the data (Hellden 1987).
The more complex transformation of data into adequate information and the need for system's analysis of the complex 'man-environment' interaction, involving huge amounts of data from different sources, calls for computer support.
Computerized modeling to simulate the environment takes - and particularly will take in the future - these interactions into considerations.
Relatively simple examples are the assessment of the agricultural potential for specific crops, as done in the land evaluation incorporated into GILES (see Section 1.4 and 2.3.1; p.7/29) or the calculation of the erosion hazard (see Section 2.3.2; p.32).
Development of spatial models of land use may be a way towards the ultimate monitoring system, where supply, demand and accessibility of resources are assessed in an integrated way. Combined models describing supply and demand are defined and applied (e.g. carrying capacity models).
d) Many of the parameters used for land resource management and essential for land use planning, are highly variable in space and time.
Spatial variability when inventorying and surveying the environment is normally accommodated by appropriate sampling density. Procedures for these are more (e.g. present land use) or less (e.g. climate) established.
But inventoried variability depends on scale, time frame of the survey and objectives of the study. More detailed survey can bring better results (maps, data) than previous exercises.
Temporal variability in environmental factors can be very high. The methodology to handle this variability is not well established.
Changes of climate, land use patterns, hydrological regimes, population, political boundaries can modify the characteristics - and the need and the potential of the land.
A reliable resource information system should always be up-to-date and corrected with the latest available figures. Changes, updatings and corrections should be entered into the archives ('data base') as soon as they are available.
This change is given through computerized storing and handling of data.
But updating is rather more than just modifying an aging data base; it implies resurvey and processing new information. The updating modifications will result in always new, corrected, improved assessments of the agricultural potential and need for - eventually new - actions and plans the land requires.
e) Often resource data are collected, but stored and organized in different institutions and in different formats. This intransparency does not lead to a high efficiency to support Government and planners with the requested information. Established links to other natural resource data bases are to permit easy exchange of data between databanks. E.g. setup of a National Soil Survey databank of Ethiopia specialized on soil data was made in conformation with GILES; meteorological data are gathered and organized by the National Meteorological Service Agency NMSA, statistical data (census figures, yield estimates) by the Central Statistical Office CSO of Ethiopia; proposal is made for a Sahelian natural resource database (CDC 1986).
If computerized compatibility is given, these data can - after being made available - be inserted into the present geographical information system.
Establishment of a computerized database is not necessarily a capital intensive activity requiring mainframe computing facilities with high costs any more. Recent developments in computer hardware and software have placed the computer power required to run a GIS within the scope of any average size office, as it is demonstrated in this Manual (for requirements, see Section 2.6; p.37).
Beside the fact that large data can be stored in a compact, organized manner, the most fundamental and the most significant advantage of computerized processing is, that data may be 'rapidly retrieved in a wide variety of formats, aggregations and manipulations' (WMO 1985).
Any land resource data base should be site specific ! Long term land use planning objectives require the identification of locations suitable - or not suitable - for a particular land use.
For planning and modeling purposes, it is not only the data being important, but rather the spatial distribution of the environmental data in form of maps, which gives the essential information where actions have to be taken. It is evident, that land users require more and better mapping information (Cunningham et.al.1984).
Presentation of environmental information in map form is a necessary tool for the planning and management of natural resources, as well as for research on the distribution and allocation of resources. Maps can be seen as a means for communication between researchers, decision makers and planners. The amount of information that can be presented in map form is tremendous. Both status, trends and projections can be presented in a conceptually simple way. To keep pace with the increasing capacity to collect environmental - and structural - data through surveying and the increasing demands of supplying data to users of all categories, the conventional data handling methods should be supplemented by modern computer assisted techniques.
Any resource data base and interpretation on spatial distribution has to combine various maps with different mapping units and to process their parameters. The mapping units of those maps might be similar (if based on the same inventory, e.g. aerial photographs), but maybe they are not at all (e.g. administrative boundaries compared with physiographic units, watershed management with vegetation units). This can only be solved by more or less small resolution mapping systems which can be adjusted to all these different boundaries.
This can be offered by computerized means - with all the possibilities described above - through so-called 'Geographical Information System': GIS. The principle of any GIS is to store spatial information as different information layers in a grid system, enabling further processing and retrieval.
The major advantage of a GIS is the possibility to integrate and analyze very large amounts of data from different sources and with different themes for computer based generation of new information layers, maps and statistics for planning purposes. The information available can be presented in optional combinations.
In review of the present state-of-art, it is apparent that there is a high, but still unsatisfied need for low-cost, easily usable GIS software running on readily available, cheap hardware that emulate the capabilities of larger specialized systems. This need tries to be satisfied by the present GILES system.
The present computerized data base of natural resources on spatial basis gives the possibility to assess land performance when used for specified purposes.
The assessment is directed towards the following objectives:
a) identify land suitable for arable and perennial cropping, livestock grazing and fuelwood production, based on assessment of soil erosion hazard, present land degradation and wetness limitations,
b) identify suitable crops, areas where they can be grown, and estimating yields under different levels of inputs and technology,
c) assessing the land resource balance relative to present and projected population numbers (population support capacity) to identify areas of particular need and areas most likely to benefit from additional investment.
The results of this land evaluation will provide a rational basis for decisions on land use which can be taken in accordance with national and regional development policies.
Exploration and exploitation of new resources, new techniques and new input levels in agriculture can increase the agricultural potential considerably. Steady change in environment, land use, economic parameters and economic evaluation makes the land evaluation timevariable. As soon as change in environment etc. is inventoried and assessed, it can be brought into the system for land evaluation.
That results in the pronounced need for new, fast executed land evaluation assessments. High need exists for fast incorporation of these eventual changes of land use into the land evaluation procedure for immediate checking of the potential of new land use practices.
As in reliable evaluation systems with applicable results many parameters (land characteristics and land qualities) have to be incorporated, there is the understanding that such a system should operate under computer assistance. This is even more true if such a database has to show spatial distributions, i.e. thematic maps.
As larger the scale, e.g. moving from 1 Mio. to 1:50,000 scale, as more data are gathered and need to be processed for the different, in more detail defined objectives of land use planning studies, which are rather for implementation than for project identification.
Generally, it can be said, that as larger the scale is, as more reliable are the results of the land evaluation and recommendations, which goes up to the level of giving site specific information, but as more complex are the models and more parameters ('land qualities') have to be considered.
This large amount of data be processed only by computerized means, otherwise a tremendous loss of information will lead to misrecommendations and misplanning.
This is the main objective of GILES.
Land evaluation exercises were executed by GILES in various areas of Ethiopia (see App.10; p.257). Several land evaluation reports with accompanying atlases are published by the 'Land Use Planning and Regulatory Department' of the Ministry of Agriculture of Ethiopia (assisted by FAO/UNDP project ETH/82/010 and ETH/87/006): FAO 1987 d; FAO 1988 a; FAO 1988 b; FAO 1988 c; FAO 1988 d.
a) Possibility to store large amount of data:
In GILES, it is possible to store, integrate and analyze very large amounts of data derived from different sources (e.g. different maps from different agencies), with different themes, different scales and different level of detail for computer based generation of new information layers, maps and statistics for planning purposes.
A standard computer storage medium (40 MB hard disk; 1988) can store more than 1500 different maps (map sheets).
b) Possibility to store all original data:
In conventional mapping systems it was necessary, to reduce the original data greatly in volume (or to classify) in order to make them understandable and representable. Consequently, many local details were often filtered away and lost. GILES makes it possible to organize the data storage without generalization, i.e. loss of data, and to generalize them only when retrieved according to request.
Each map stored in GILES can have up to 700 different mapping units (e.g. soil types shown on the map). For soil and administrative units up to 50 parameters ('attributes') can be entered and retrieved (e.g. drainage, texture, depth, population density, population support etc.).
c) Selection of level of detail:
The level of detail shown on the map produced by GILES can be selected by the user. The degree of map generalization can be chosen, depending on the scale and the purpose.
d) Flexibility of scale:
GILES enables print or plot of the requested map within a wide scale range (e.g. thematic maps of Ethiopia at a scale of between some 1:500,000 and 1:6 Mio).
e) Combination of maps with other maps (spatial data):
GILES' maps can be overlaid and combined with other maps or map overlays (!). It is possible to consider the interactions between different ecological parameters or between physical and administrative units.
Maps can be shown with requested attributes of up to 10 different base maps. Up to 5 crop suitability assessments (maps) can be overlaid to form a crop mix ('farming system') suitability assessment.
f) Combination of maps with non-spatial data ('attributes', 'parameters'):
Maps can be retrieved in combination with entered non-spatial data in a specified content through translation tables (e.g. 'parametric maps', see Glossary, p.267).
Of the soil map e.g. 50 individual parametric maps can be retrieved with the translation table 'soil type characterization'.
g) Correction and updating facilities:
Printed maps are static, qualitative documents, almost impossible to be changed. 'It is extremely difficult to attempt quantitative spatial analysis within the units delineated on a thematic map without resorting to collecting new information for the specific purpose in hand' (Burrough 1986).
In GILES, corrections due to a better survey, more reliable data base, updating on a monitoring basis, changes in the environment, new delineation of administrative units etc. can easily be inserted and hereby corrected maps or statistics can be printed.
Not only the data are continuously to be checked and corrected, it is also the interpretations of the data, the modeling, which can be revised due to new requests, new approaches or new purposes (e.g. different scales, different requirements).
h) Facility of modeling:
Many advantages accrue when emphasis is placed on manipulation, analysis and modeling of spatial data in an information system.
This potential for dynamic simulation and modeling is offered by GILES. A number of options and scenarios can easily be modeled and compared with each other (e.g. what is the quantitative advantage to drain a certain area). 'What if ?' analyses can be executed.
To overlay various spatial data with the incorporation of models ('algorithms') to assess the agricultural potential and the environmental interactions is the main activity of GILES. A large number of varieties of modeling is possible (the assessment of agricultural potential, its need to sustain productivity etc.).
i) Speed of map print:
Processing of a map is faster than manual drawing of a map.
j) Error quality:
In any manual and computerized mapping system, it is impossible to avoid systematic errors completely. Advantage of GILES is that these errors can relatively easy be checked and corrected.
Random errors (e.g. 'human errors') as they always might occur on hand-drawn maps, will be avoided by GILES.
k) Wide range of output forms:
GILES offers a wide range of different output forms: Maps plotted with boundaries of the units, colored or black & white maps on plotter, maps on matrix printer with font symbols or with gray scale, maps on computer storage media for later outprint, only legends of maps on screen, printer or in spreadsheets. These maps can be retrieved for the entire area or only for selected parts or small windows (see Section 3.2.3; p.98).
a) Necessity of computer facility:
At least one Personal Computer with peripherals ('hardware') is required, as listed in App.4 (p.200). Costs for the purchase of one hardware set is in the range of 1500 - 4000 US$ (1989, with tendency to be less in future; see Section 2.1; p.17).
Power supply (electricity of 220 V or 110 V) is essential.
b) Know How of personnel:
To run any kind of computer equipment, manpower trained in the use and maintenance of computer is essential. For the application of GILES, interactive manuals and help menus offered during information request can train users within a few days time (see Section 2.6.2; p.39).
More difficult is the installation, maintenance and repair of computer. For this, expertise at the level of good basic understanding of technics and electrics is required.
In many developing countries, service is not offered by computer dealers or manufacturers. In Ethiopia, most computer hardware service is done by individuals getting acquainted with computer hardware at various levels.
c) Data entry of base maps:
Before retrieval or processing of maps or data, base maps (e.g. topography, soils etc.) have to be entered ('digitized') into GILES.
Even though particular emphasis was given to efficient and user-friendly way of map digitizing, this can still be a bottleneck of the system. Digitizing, in spite of modern table digitizers, is time-consuming and enervating work: a drudge (Burrrough 1987).
E.g. to enter a relatively detailed map of Ethiopia at a scale of, let's say, 1:1 Mio. might take some 20-70 man hours (see Section 2.5.1; p.36).
d) Unawareness of clients:
The Government, ministries, development agencies and other potential clients are not fully aware of the advantages of a fast computerized information system providing the essential information within hours time. Thus, the necessary structural changes in work and information flow and practices that would allow the advantages did not take place yet (see Section 2.1.4; p.19).
e) Limited output graphics:
In the present GILES version (2.2) automated cartography is not fully established yet and therefore output quality can not always be considered equal to well performed manual cartography.
'Only the use of the information produced by information systems can justify their existence: information systems have to support decision making.' (de Meijere/van de Putte 987).
The assessments of the agricultural potential with and without improvements will guide the formulation of land use plans through which this potential can be realized.
Beside the evaluation of areas or of crops being suitable, the planner can, based on political priorities, define rules for the identification of the areas with the highest potential or with the highest needs for soil conservation and for an estimation of the cost/benefit relationship in each of the areas selected. The characteristics selected to identify the areas might be any combination of a high population density, a low available land/capita ratio, a high, but not increasing annual crop yield, a high precipitation variability, a medium or high soil loss or a specified slope.
Because planning is concerned with the future, the essence of planning is making projection of developments over a certain time period. The first projection that must be made in any planning exercise is the 'autonomous' development situation ('the "without" situation'). This reflects the development of processes as they will take place without (new) actions being taken.
A plan indicates a set of actions to steer the process in the desired action, with assumptions made and changes to the environment. The new scenarios can be evaluated. This can be done easily if the assumed actions are integrated into an information system and characterize a new, improved situation ('the "with" situation').
To be able to make projections for a proposed set of actions, it must be possible to indicate in quantitative terms what the effects will be. The elaboration of scenarios used to be a very laborious task and therefore only a limited number of alternatives were used for decision making. Computer analysis facilitates this process and therefore enlarges the scope of information available for decision making - and improves the quality of the output and reduces the chances of misplanning.
Because these data can be accessed, transformed, and manipulated interactively in a geographical information system, they can serve as a test be for studying environmental processes or for analyzing the results of planning decisions. By using GILES in a similar way that a trainee pilot uses a flight simulator, it is, in principle, possible for planners and decision-makers to explore a range of possible scenarios and to obtain an idea of the consequences of a course of action before the mistakes have been irrevocably made in the countryside itself.
It would be a tremendous and practically impossible task to carry out such operations manually by combining and comparing map sheets, with different themes, scales and ages, with each other.
It is only when the system has been made 'dynamic' that it can be used for making projections and therefore for planning, but it is also the dynamic aspect that is difficult to quantity. This emphasis the importance for planners to have a tool which enables them to test the effects of various alternative actions and to assess the impact of the sensitivities on the assessment criteria related to the objectives.
Specialized GIS systems 'are emerging as the major spatial data handling tool for solving complex natural resource planning problems' (Nystrom 1986).
But development 'continued so fast that it outstripped the ability of managers to keep up. Under these circumstances it was difficult for them to remain objective and to think of how the new technology was really addressing the fundamental problems of mapping.' (Burrough 1986). At the present, GIS systems are not being used as effectively nor as widely as possible for natural resource assessments.
It was shown in this chapter that microcomputers have the potential to become a standard tool for resource managers in decision-making, but the most important is that resource managers are aware of the powerful tool they have in their hand and know how to use it in the most efficient way.
With further development and higher acceptance of decision makers it can be assumed that GILES will lead to considerable improvements in agricultural and environmental management and control in Ethiopia in the future.