Technical Session – IV

A GLIMPSE OF THE GIS ACTIVITIES IN NEIGHBORING COUNTRIES

GEOREFERENCING CADASTRAL MAPS IN THE PRETEXT OF DIGITAL CADASTRE

Durgendra M Kayastha
National Geographic Information Infrastructure Project
Survey Department
HMG Nepal


ABSTRACT

For most of the local application, land forms an integral part of the system, thus cadastral maps form the basis of such application. But availability of cadastral maps especially in digital format is still a problem area. Immediate new mapping may be a near impossible task considering the time and resources required for preparing such maps of the entire kingdom; hence efforts should be made towards utilizing the existing maps to create a digital cadastral database.

Analogue map-based land management cannot support the overwhelming demand from the user communities for the land-based information. Digital processing on the other hand would possibly be very efficient due to ease in operation and processing efficiency may, therefore, be dramatically improved.

Conversion of coordinated cadastral maps as well as island maps to digital format is, therefore, needed. For coordinated maps, the process is straight forward, whereas, in case of island maps, geo-referencing is a crucial task. For compatibility, and also to establish a seamless database geo-referencing of maps is a must. Conversion of existing maps to digital format may possibly be the optimum solution.

Some of the problems associated with the conversion process are - unavailability of reference coordinates, physical condition, level of update of details, changes in land use type, and mismatching of details at the edges of the maps.

In order to reference the maps, it would be necessary to select sufficient number of points (features) on the map, that may be identified clearly on the ground. The main problem however would be to find such common points in sufficient numbers as the maps are very old. Based on the common points acceptable transformation is found the rest of the procedure is to digitize individual sheets following the standard specification as to feature coding, attribute coding etc. followed by processing of vector data for geometric editing, building of topology and edge matching etc.

However building control points database may be a big task taking long time considering that such group of points would be required for each individual sheet. GPS method could be a ready assistance in this regard, yet the time required may still be not acceptable. However this is the best method one could adopt.

Alternate solutions may, however, be adopted sacrificing the geometric accuracy of the vectors for a while to make up for the time and avoiding immediate resource allocation.
Digitize the map registering it to the local grid drawn. Create vector database based on the local grid on sheet basis.

This way one can have digital cadastral layers based on individual sheet grid. Continue using the sheet based vector database for general land administration until the time when a single national coordinate system would be applied to all sheet-based database. However, due to independent coordinate system in each sheet, adjoining sheet data may not be edge matched or joined to form a seamless database. Data layers thus obtained would be a direct translation of cadastral sheet to digital cadastral sheet only, however it will facilitate working in digital environment.

Digitizing of maps and thereby creating a database accounts to almost 80 percent of the works in development of a seamless geo-spatial database. So national coordinate system or arbitrary coordinate system, the process of digitizing is the same and takes same amount of time. Without waiting for determination of transformation parameters for individual sheets one can start digitizing them. Once digitized, transformation to national system would entail minimum time once the transformation parameters are ready. Thus work could progress simultaneously in two fronts, viz. digitizing to arbitrary system and measurement for transformation to national system of coordinates.

Creation of geo-spatial database is a long process, but the regular land administration cannot be halted until the system is up and running. So two pronged, phased approach of converting the existing cadastral maps to digital cadastral database is proposed herein. This is especially suited for the case where two different types of cadastral maps are in use. Creation of database to national specification using coordinated sheets may proceed following standard procedure in one side while local grid-based database be created using island maps complemented by control points measurement for determination of transformation parameters on the other. It should however be noted that the accuracy of data created using these approach be closely monitored and modified to make such data acceptable to the database.



APPLICATION OF SATELLITE REMOTE SENSING ASSOCIATED WITH GIS AS A SUPPORTIVE TOOL FOR THE DEVELOPMENT OF RIVER BASINS.

K.M.P.S.Bandara, Department of Irrigation, P.O.Box 1138, Colombo, Sri Lanka.


ABSTRACT

With increasing of pressure on natural resources, patterns of land and water use are in a state of change. Strategic or long-term planning for the development of river basins is one of the key objectives of managing land and water, at local level. Determination of spatial and temporal variations of land surface conditions make a significant contribution for the planning of natural resources development, especially on land and water. Land surface conditions can be considered, as a spatio-temporal continuum in which processes of different kinds take place and such processes could be the development of vegetation, water, landuse etc. Each process is the resultant of interacting forces caused and affected by internal and external factors and will lead to spatial patterns of terrain characteristics, which will change with time. The terrain descriptions refer to these spatial patterns, each pattern is then considered as a state of such a process at some specified moment. In this context, acquisition of real time data, fast processing techniques and management of information system for different user requirements provide better opportunities for river basin planners.

Researchers in various national and international programs have shown increasing interest in using satellite measurements for the determination of land and water use patterns. These studies have demonstrated that quantitative assessment of the atmosphere transfer process of soil and vegetation can lead to a better understanding of the relationships between plant growth and water use. Evapo-transpiration is an important factor in water balancing of river basins. Remote sensing produces the spectral measurements that provide biophysical input data needed to determine actual and potential evapo-transpiration. This information can help solve basic issues on regional scale water use and water requirements. Growth of biomass or plant growth occurs through the mechanisms of photosynthesis and carbon assimilation, which needs light in the visible part of the spectrum, beside carbon dioxide and water as major inputs. Remote sensing techniques are now being used for the estimation of biomass and crop yield variations from AVHRR satellite measurements. Performance assessment of irrigation systems is as essential component of river basin management in Sri Lanka in case of increasing the food production of the country. Remote sensing may now provide viable solutions in some situations, allowing repeated sampling of field conditions in units as small as 100 ha. Satellite data acquired for the estimation of land surface parameters can be easily used for land surface classification (thematic classification) and delineation of permanent and semi-permanent features such as streams, roads, urban areas, forests etc.

In the process of topological and hierarchical object modelling for Geographical Information Systems (GIS), the emphasis will be on the relationships between the geometric and non-geometric (thematic) aspects of the terrain descriptions. Availability of past data as well as current data makes this process successful. But, unavoidable time delays encountered in traditional field surveying techniques obstruct furnishing real time data. The time factor is rather dependent on the capability and rapidity of acquisition and receiving field data. Therefore GIS associated with Satellite Remote Sensing will solve the time factor at a considerable extent and could be used as a supportive tool for the development of river basins.


GIS APPLICATION FOR LANDUSE PLANNING, BHUTAN

Deki Wangmo
GIS Unit, LUSS, PPD
Min. of Agriculture, Thimphu, BHUTAN


ABSTRACT

Beginning from mid 1980s, the government of Bhutan has increasingly used Geographical Information Systems (GIS) for natural resources planning and management. The Department of Forestry was the first organisation to establish a GIS Unit using ESRI product Arc/Info software. This department used GIS for mapping forestry types and preparing forestry management plans. Its coverage was, however, quite limited and the benefits of GIS couldn’t be used to its maximum. The required information was still not available especially in digital format.

In 1992, the Royal Government of Bhutan (RGoB) and DANIDA agreed on a Land Use Planning Project (LUPP). Among various components, an important one was to collect all the required information and develop base data. This was to be done through the application of GIS. The first step was to gather all the available information that could be entered into a GIS database. LUPP bought topographic maps and SPOT Panchromatic satellite images covering the whole country. Initially, all features from the topographic maps that included contour lines, hydrography network, administrative boundaries, roads and settlements, were digitized covering the whole country. This went on to form the first digital topographic database for the Bhutan. Once this was completed, the panchromatic satellite images were used for mapping land use and land cover through desktop work, field visit and with the help of district officials.

Output from the above activities included a land use-working map at 1:50,000 scale and the relevant statistics. The draft products were sent through a process of quality check both in-house and from the districts. After making the required changes and incorporating the feedback, the final land use working maps were produced. These maps were latter combined to prepare the district land use and land cover maps for twenty districts in Bhutan. Later, these district maps were used for the preparation of a national land cover map at 250,000 scale. Land cover information, with additional description of the district, was also compiled in the form of The Atlas Map of Bhutan.
It was already the end of 1994 by the time we have achieved this much. But, all in all, it was a great achievement not only in the application of GIS but more importantly in what GIS has done to us – the creation of an important digital database for the country. From then on, the journey ahead was much smoother.

As one important component of the LUPP, four Plilot Studies were conducted in different parts of the country covering different agro-ecological zones. This was done mainly to test the applicability of the knowledge, database and experiences gained so far in land use planning taking the case of some small representative areas. The base data available with LUPP was very useful in preparing various thematic maps and carrying out some of the required analysis.

Besides fulfilling the GIS requirements of various customers from outside the ministry, an important activity included the preparation of block land use maps. This was done as part of the government’s policy of block-based developmental planning during the coming 9th Five Year Plan.

It is also relevant to note that a lot of other organisations that started to use GIS took their base data from this office. They include the Forestry Department, WWF, Nature Conservation Division, National Soil Services Centre and the Department of Geology and Mines. Apart from providing base data, LUPP was also able to train quite a number of people and took some of them for apprenticeship.

Within the ministry, the GIS operators were trained from the four regional research centres after which they provided with the base data and the required GIS facilities. Today, they are fully operational and have been able to share a large chunk of the workload of the centre (LUPP).

Present activities include updating the existing land use and land cover information and maps. The office acquired Landsat TM images of 1998-99 covering the whole country. About 65% of updating work have already been completed. Such activities will continue in future too and we will need to acquire additional satellite images.

The main GIS software used include ESRI product Arc/Info, IDRISI, TIN, ArcView and for remote sensing – ERDAS IMAGINE.


POTENTIAL FOR GIS BASED TECHNOLOGY FOR COMMUNITY FOREST BOUNDARY SURVEYING IN NEPAL

Krishna Acharya and Ananta Parajuli


ABSTRACT

Two GIS based methods- GPS and Orthophotos Use

Forest boundary surveying is an important planning tool for hand over process in Community Forestry (CF) in Nepal. It is a mandatory activity required for the formal hand over of a government forest to the local users. Presently in CF at least five different boundary-surveying methods are in practice. The most commonly practised surveying system in the CF is Chain and Compass survey. In this system maps are generally prepared by joining the straight lines with little or no references. Consequently such maps are less informative and less useful to rural people. On the other hand, CF in future requires surveying and mapping of a huge number of community forests for the hand over process and also for the up dating of the existing Operation Plans. To prepare quality maps and to meet this target within limited time, there is a need of an alternative surveying technique having the potential to replace all surveying practices so far applied in CF. Such technique must be accurate and produce quality maps efficiently. As in Nepal land ownership receives highest social recognition especially in the rural areas where CF is being implemented. The paper suggests the need for more discussion and interpretation on the issue. It is recommended to explore the potentiality of combining existing surveying system and GIS based techniques in CF boundary surveying and mapping.


BANQUET DINNER LECTURE
CURRENT RESEARCH ISSUES IN GIS

Michael F. Goodchild, University of California, Santa Barbara
USA


ABSTRACT

The paper addresses four issues at the forefront of GIS research. First, many of the frustrations encountered by GIS practitioners stem from the long elapsed time characteristic of many projects. Although GIS analysis proceeds at electronic speed, the majority of project time is spend in preparing data, by digitizing, scanning, and retrieval from archives. Paradoxically, the arrangements adopted for production and dissemination of geographic data contribute to this, by making it far easier to retrieve many data sets on the same theme for different areas, than many themes for the same area. Recent research in digital libraries, and in search mechanisms for navigating distributed archives, are promising to revolutionize arrangements for data dissemination. The Alexandria Digital Library is a large instance of a geolibrary, a digital library designed to be searched for information about a specified location. The current state of research in this area is described.

Second, quality of geographic data continues to be a major issue for research, since all GIS results are to some degree uncertain. This research involves the identification of sources of uncertainty and error; the description and modeling of uncertainty; methods for visualizing and propagating uncertainty to obtain measures of confidence in results; and methods for incorporating uncertainty into the decision-making process. The state of research in this area is described, and examples are given of the severity of the problem and of the progress that has been made in the past decade.

Third, GIS is in many ways a technology of static geographic information, and methods for representing and analyzing temporal change continue to be elusive. Recently there has been much interest in the research community in geocomputation, or the use of computational methods to simulate processes operating in the real world, and modifying aspects of the human and physical landscape. In addition to representing knowledge of dynamics, the primary purpose of such models is prediction, and the evaluation of what-if scenarios. Examples are given, and recent research on the requirements of an infrastructure to support easier sharing of models is described.

Finally, technology has now advanced to the point where it is possible to consider performing GIS functions in the field. It is now possible to provide all of the services associated with a desktop computer, including communication, storage, processing, and output, in a computer than can be worn on the human body. The implications of wearable computing for geographic field work are exciting, and provide an instance of a class of location-based services, or services provided by included in the presentation.