S Krishna Raj Adhikary
Kha-1-126 Bhimsengola Baneswor
Email: [email protected]
Understanding change in surveying and mapping activities requires interpretation of the present in terms of the past. Knowing change in the past will prepare us for the future. In Nepal, the history of surveying and mapping activities excluding cadastral survey is not so long. Surveying and mapping activities up to 1970s AD were mainly concentrated on the preparation of cadastral maps and related documents. The Geodetic Survey and Topographical Survey in Nepal was established during 1970s. The initiation to define the spheroid with projection system and the national datum of the country was taken during those period. Earlier the system of map projection and preparation of topographical maps were all done with the help of Survey of India through Colombo Plan agreement. The ground control system were prepared by extrapolating the trigonometric control network system of India and adjacent countries.
Twenty-five Years in Retrospective
Survey Department was established, as a department status of the His Majesty’s Government of Nepal, in 1975 AD. Topographical Survey, Geodetic Survey, Cadastral Survey and Survey Training Centre are the main branches of the department. Aviaries function were carried out by different branches of the Department during past twenty five years. What are the major changes in the field of surveying and mapping activities during past twenty five years of time? There are a number of specific development which are changing the faces of Survey Department.
- Establishment of napigoswara and preparation of cadastral maps/documents in national level in 1964 AD.
- Completion of a series of cadastral maps of cultivated areas for all the seventy five districts of Nepal.
Fig. 1: Administrative infrastructure of cadastral survey
- Establishment of Geodetic survey in 1971 AD.
- Establishment of higher and lower order national Geodetic control network.
- Establishment of lower order national levelling net work.
- Establishment of observatory tower, base stations, gravity station and laplace station.
Fig. 2: Infrastructure of geodetic survey
- Establishment of Survey Training Centre in 1969 AD.
- Production of different level of survey technicians (Basic, Junior and Supervisory level).
- Updating knowledge on surveying and mapping techniques for working surveyors by refresher courses on various subjects.
- Establishment of topographical survey in 1976 AD.
- Establishment of aerial survey lab, installation of photogrammetry, cartography and printing equipments.
- Preparation of aerial photos of whole kingdom of Nepal (1979 and 1992 AD) at 1:50,000 scale.
- Preparation of land use maps (at 1:50,000 scale) and subsequent report of whole kingdom of Nepal 1980 AD.
- Preparation of topographic base maps (1:25,000 and 1:50,000 scale) of whole kingdom of Nepal except some portion of north-western region of Nepal.
- Preparation of Nepal China International boundary maps (1979 AD).
- Preparation of large scale maps of specific regions of the country.
Fig. 3: Organisational structure of Ministry of Land Reform and Management
The Survey Department is one of the three departments of the Ministry of Land Reform and Management. Survey Department has four different branches, the activities of them are as follows: (a) Establishment of national network of horizontal and vertical control points, (b) Prepare and update topographic base maps and other types of maps, (c) Prepare and update topographic base maps and other types of maps, (d) Human resource development in the field of surveying and mapping, (e) To conduct and monitor the surveying and mapping activities of the country. Geodetic Survey Branch of Survey Department has different sub-branches e.g. Trigonometrical gravity, GPS, Astronomical, Levelling and Survey Computation. Similarly, topographical survey has the following sub-branches: Photogrammetry, Field Survey, Cartography, Printing, Boarder Survey, and Integrated Survey. The proposal is to merge survey maintenance offices of Survey Department and District Land Revenue Offices in one office. Survey Training Centre will act as Land Management Training Institution under the Ministry with the departmental status. Land Information System and Land Archives Department will newly be established in order to have an integrated Land Information System with central level archived. The name of the Land Revenue Department will be changed as Land Reform and Land Management Department after merging Land Reform Department into Land Revenue Department.
Today surveyors are familiar with a new generation of surveying equipment and techniques. Traditional system of surveying and mapping has been replaced by semi-modern or modern techniques that can be characterised as ‘black box technology’, giving results in real time and in digital form. Many of the surveying activities including field operation have been using ‘Push of Bottom’ System with limited use of knowledge and experiences of the survey professionals. This technical evolution has influenced the instrumentation and techniques used in surveying and mapping. In Nepal, plane table surveying for cadastral survey is still popular. More than 2000 surveyors are still working on this technology. However, topographical surveying is carried out using aerial photos with photogrammetric analogue plotter and geodetic surveying is still using triangulation traversing by theodolite and distance metre. Higher order geodetic controls and precision levelling works are carried out by precise theodolite and levels. Attempts to automate and make the surveying and mapping process more efficient, have also been going on for considerable time.
GPS Methods for Control Points
Global Positioning System (GPS) was used in the production of topographical base map for Eastern Nepal, Topographical base maps were at 1:25,000 scale in the plane and 1:50,000 scale at the mountain. The aerial photography was taken with the help of kinematics GPS techniques in order to have the minimum control for the aerial triangulation singular on an unaccusable Himalayan part of the country. Similarly, the same method was used for the Western Nepal Topographical Mapping Project. The extension of ground control for large-scale cadastral maps is also carried out by GPS methods.
National Topographic Data Base
The utilisation of digital geographic information has been growing fast in all sectors of the society of the world. Also, in Nepal, this has given a great influence to different organisations and in some of the sectors of society. Recently, Survey Department has already prepared the specifications for geographic information service and national topographic database to ensure homogeneous quality and availability of needed geographic information with this national database standard. Survey Department runs digital mapping applications on environment. It is utilising cadcore/Tracer software for on-screen vectorising and ARC/Info as their editing and map use software. ARC/Info database is used as data storage format. Digital geographic information is also used in producing graphic maps. The objective of the product specification is to ensure the sufficient information content for the user and the specification for topographic maps at the scale 1:25, 000 and 1:50, 000 are aiming to fulfil the needs of users, as most updated maps of most of the regions of the country are easily available.