National survey organisations in many countries are under pressure to change their working procedures and to expand their activities from the conventional base-maps production to the creation of digital topographic database
Geographical Information System (GIS) technology is conceptually dissimilar to traditional mapping. These differences in traditional and modern result in an asset and a liability. On one hand GIS offers powerful tools to address complex issues in entirely new fashion; on the other hand, these new tools are unfamiliar and pose challenges to many of the fundamental concepts we have developed over the past many centuries. GIS technology is struggling in its transition from the researcher to the general user level. The user community generally tends to define GIS in more comfortable terms of computer mapping and spatial database management. The fundamental advantage of GIS is that it affords to merge many features of digital mapping in addition to its inherent properties.
Many technologists propagate the idea about the “unlimited” potential of GIS. But the challenge is to carefully separate what you have in two piles, the quixotic dream and the pragmatic reality. GIS means different things to different people. To surveyors of old generations, GIS is a topographic database but for users of other disciplines, it is an information system or a decision making tool. However, in general and widely accepted terms, GIS means accessing information which hitherto before was not available on the conventional maps. These basics are the corner stones of GIS. They automate our historic map analysis procedures and provide a foothold on the technology. However, this perspective limits the full potential of this new technology.
The GIS capabilities that excite enthusiasm among potential users are the ability to change the map scales and the ability to overlay maps at random. Both capabilities are indeed exceedingly useful; they constitute much of the comparative advantages GIS holds over spatial analysis based on analogue maps. Both capabilities may also mislead decision makers who are unaware of the imprecision inherent in all cartography and who are untutored in the ways the errors compound when map scales are changed or maps are merged.
Application of GIS technology developed around the world
Many of the early applications in Europe were built in landownership and registration system and environmental databases. However Britain had a very large expenditure in the 1980s for developing utilities information.
Canada developed an important forestry application to plan the volume of timber to cut, identify access to the timber, and report the results to the provincial governments. Applications in China and Japan emphasised monitoring and modelling the possible environmental changes.
In the United States, the US Bureau of Census and the US Geological Survey used GIS technology for their Topographically Integrated Geographic Encoding and Referencing (TIGER) project. They produced a computerised description of the US transportation network at a cost of about $ 170 million to facilitate reporting of the 1990 census.
National Survey Authority of Oman (NSA), a government organisation, is an established survey mapping agency of this country. The main responsibility of creating data base may be lying with the same as in other developing countries of the world. The data base is created by digitising the old paper maps or aerial photographs. Mainly topographical information is available in the maps of Oman. However, information which can be indirecly obtained in one or the other way from these products is about:
- Soil classsification
- Main crops
- Landuse / Landcover
- Land Information
- Many more other information
Other agencies in the country may also collect (or plan to collect) and create a comprehensive topographic database for the entire country. GIS supports the daily activities of automated mapping and facilities management with applications for transportation planning, electricity, water, sewer, gas, telecommunications and cable-television. Utilities using capabilities such as load management, trouble call analysis, voltage drop, base map generation and maintenance, line system analysis, network pressure and flow analysis and leak detection and inventory etc.
Demographers use GIS for target market analysis, facility sitting, address matching and geocoding as well as product profiles, forecasting and planning. GIS also has an increasing role in supporting education and research in the class room, the computer lab, the research institute, and the public library. The most important point to note is that these diverse applications are carried out using similar software and techniques. A GIS is truly meant for as a general purpose tool.
Need for Digital Topgraphic Information
Digital technology was successfully introduced in the field of mapping in the late 1960’s as a means of speeding up map production and particularly the plotting and fair drawing phases. It was not until the mid 1970s that the information perspective began to be drawn and digital map data was seen to have value by itself, besides being the data source for the traditional printed maps.
The changing technology in the last two decades has created the possibilities of achieving new tasks as well as providing new ways and alternatives of carrying out the existing tasks. With the growing number of spatial information systems, already developed or still under development, for the interpretation and the analysis of the spatial data in various disciplines, the following trends have been observed in the geo-information community: Topographic information in digital form is being increasingly used in parcel mapping, public safety and environmental planning. Resources managers rely on GIS for fish and wild life planning; management of forest, agricultural and coastal lands; and energy and mineral resources management.
Topographic information in digital form increasingly needed. A shift is being realised from the supply of digitally encoded geographic maps towards the delivery of more structural information where the topological relationships among the various attribute-features are explicitly represented in the data. Also a shift from the collection of digital topographic data on an ad-hoc basis to satisfy specific project requirements towards the creation and maintenance of a topographical database that can be used continuously by all users.
As a minimum requirement, the digital topographic database should include all features traditionally included in the topographical maps. Users need to know the quality of the product which they intend to use (contents and its classification, completeness, up-to-dateness and temporal validity, conformity with conventional mapping standards etc.).
Role of National Survey Organisations
Accordingly, national survey organisations in many countries are under pressure to change their working procedures and to expand their activities from the conventional base-maps production (i.e. the systematic image coverage and base mapping of the national territory) to the creation of digital topographic database. Its objective is to improve the responsiveness to users expanding demand for topographic information to be supplied in digital form with specified format and to provide the base on which a series of GIS operations can be performed.
Measures currently being undertaken by mapping agencies to achieve this goal include:
The establishment of an efficient mechanism in order to provide awareness of potential users and determine the realistic information requirements of these users and the nature of spatial processes which they are involved in. The establishment of digital mapping standards for data collection, data structure and organisation, data storage and exchange of data.
The conversion of existing maps and any available digital data that had been produced in the past into the required data structure. This includes the modelling which have to be carried out.
Problems in Creating Digital Topographic Database
Non-stability of Technology Digital mapping technology which started during the 1960s has not yet stabilised because the capability of computers are improving significantly. In the 1990s the technological progress was faster than ever, for instance the price of a given performance is nearly halving every year in terms of hardware. Now should a developing country with limited resources wait for the technology to stabilise or invest in the existing technology. Benefits of digital topographical database (DTDB) in a country is difficult to quantify. Secondly, will the need of DTDB be substituted to a great extent in a near future by cheaper alternatives like feature coded raster data or geo-referenced high resolution satellite imagery. Or may be automatic vectorisation from raster data becomes a complete success for topographic maps. Such uncertainities are very high at the moment.
Conflicting requirements of the users
Manu users want the data from the largest scale topographic maps whereas some others want the data as early as possible. Digitisation of all maps in a country like Oman will take several years. Even advanced countries like France estimate about 20 years to create DTDB of 1:25,000 scale resolution. Benefits of Digital Data Base (DDB) will not be realised fully until the DTDB is complete. So a compromise is to be made between scale and time. USA made its first DTDB of 1:2 Million resolution for the entire country. This data includes political boundary, transportation and hydrology. After that it started to create DTDB at 1:100,000 and more recently at 1:24,000 scale. Users in essence, may not even know what they want nor they are geared up to utilise the data.
Top management is sometimes not updated on the latest technology and its applications. Top down approach of decision taking makes it worse as some times middle management have reservations about such decisions. The planning team is forced to deal with management issues. In multi-disciplinary organisations, the co-ordinations at times lacking between digital mapping sections and other conventional sections such as photogrammetry, field survey etc.. Another important aspect is that computer oriented technology is new and senior level managers lack interest as well as confidence in it. Persons with superficial knowledge when entrusted with the task can create confusion at least in the initial stages of implementation. However, some of the well experienced leave for greener pastures. This can only be avoided by having contended staff by compensating them properly. The major management problem is that by nature, conventional oldies resists changes as he is comfortable in the role he was playing.
Hardware and Software Problems
The hardware and software are mostly imported and the vendors tend to dump the obsolete products if the buyer is not educated about the technology. Once purchased the problem will be compounded in the form of maintenance. The vendor does not have the required infrastructure to maintain sophisticated systems. Sometimes it may be wise to purchase new hardware since after three to four years the software becomes outdated. Thus instead of spending funds on obsolete systems it is better to buy newer system as the life cycle of these systems is not more than 4 to 5 years.
Poor Design of DTDB
Generally, enough time is not spent to create a well defined and thorough specification for DTDB as the organisations are eager to show some results. Poorly designed or incomplete specifications can lead to generating worthless data, resulting in huge loss. Locating major errors and editing them is very expensive and time consuming. The mental block of cartographers while designing the DTDB tends to give more weightage to reproduce the map rather than making it suitable for GIS application. Conceptual modelling of DTDB may be hardware or software dependent.
National Mapping Agencies will no doubt be having requisite data chosen for the proper resolution and scale in the topographic maps. However the major problem is to get the additional data and attribute data for the terrain features which does not exist in the map.
The external views generated by DTDB will have to be done by integrating the user data with DTDB. A national committee has to be formed to monitor the activities for proper co-ordination between the mapping agency and the users.
Any new technology will take some time for it to be accepted and percolated. The management has to be patient and should not expect quick results in a situation such as DTDB which is still nascent and in the domain of researchers. The national level co-ordination is an inescapable requirement without which no high resolution DTDB is possible. The national mapping agency which is a natural choice for carrying out this task has to perform the following functions with the help of a national co-ordination committee:
- Command, Support, Standards
- The resource data gathering and preparation
- Database management and database services
- Information extraction and integration
- Product generation
- GIS services and assistance
A suitable agency should be created in view of the enormous work. For an existing agency which may aleady be burdened with its own responsibilities, it may not be possible to take up extra responsibilities of such a huge task. The mapping agency has to be invested with the required authority to discharge the extra responsibility. On the part of the agency itself, it has to create the awareness among the decision makers and users.
Many organisations in the developing countries like Oman learn about the problems in implementation by trial and error. While the users are clamouring for data, useless data is generated and the hardware and software becomes obsolete in the process. In todays profit driven economy, the organisation may lose the interest in the case of not getting matching returns to the expenditures incurred. Some users start creating their own DTDB resulting in duplication of efforts and infrastructure. Even if they manage to generate some data it will be of no use due to lack of professional expertise and experience. Some of these problems are well documented in the case of developed countries. A country starved of resources cannot afford to repeat the data that too in a non-professional way. In a number of developing countries it has been noticed that the duplication of data is being generated in the hunger of going ahead of others by non-professional people with half knowledge about the data structure and its relation to the accuracy on the earth position of such data.