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Manipur
Manipur is one of the seven North-Eastern States in India with a total area of 22,327 sq. km.and a population now of just over two million. Imphal, the centrally located capital has an elevation of about 800m above sea level .To the east and south east of Manipur is Myanmar, to the north is Nagaland ; to the west is Assam and to the south-west is Mizoram(See Figure 1). In 1991 the population of Manipur was 1,837,149. There are nine Districts :-

Valley : -Imphal (East pop 330,480) & (West pop 380,801), Thoubal(pop 293,958), and Bishnupur(pop 180,773)

Hills : Senapati (pop 208,406), Ukhrul (pop 109,275), Chandel (71,014), Churachandpur (pop 176,184) and Tamenglong (pop 86,278)

The Imphal Valley (1,843 sq km) is surrounded by hills which rise in places to 3,000 m. Another smaller valley at or near sea level lies on the western border between the Barak and Jiri rivers (395 sq km).. Whereas the valleys comprise about 10% of the land area they are the home to over two thirds of the people. Loktak Lake - the largest in NE India lies in the Imphal Valley varies in size from 60 to 260 sq km depending on the season.

The climate is pleasant with temperatures ranging from 0 to 38 degrees. Rains occur during the south-west monsoon generally from June to September and weather is cooler and drier for the remaining months. At the airport the rainfall May through August averages 225mm compared to 35mm November through March. In the hill regions the steep gradients create fast run-off of surface water leading to low water retention in the soil and also to landslips interrupting transport communiucations. Due to poor drainage the rains cause many roads to become impassable.

The oldest rocks in Manipur include shales, slates, siltstone, sandstone and quartzites. Geologically, Manipur can be said to belong to recent formation, which has implications on the prospect of mineral exploitation. The surface rock is loose and soft in nature and, therefore vulnerable to the weathering process. This peculiar characteristic also accentuates erosion, silting and sedimentation.

Hill soils being acidic are not suitable for much plant growth and traditional shifting cultivation together with indiscriminate cutting and burning of forest (jhum) over the years have seriously affected the ecological balance leaving the soil barren. In the valley region the deep soils are poorly drained and low in available phosphorus content. They are also susceptible to flood hazards. Peat soils are found in the low lying areas and marshy lands around Loktak Lake.

In 1987 the total length of surfaced roads including National and State Highways, Major and Other District Roads and Inter-Village Roads was 4,279 km..

Manipur is one of the least industrialised states in India. Limited infrastructure and inadequate power supply do not help this situation.

The PCCS Project (Project Co-ordinating Consultancy Services)  
The Government of India is proposing, with the help of a World Bank Loan to prepare a major states' roads upgrading, major maintenance and rehabilitation programme with the aim to stimulate economic development by improving accessibility.
The project started with the Strategic Options Study; the result of which was the identification of 1,300 km of State, Major District and Other District road to be assessed in more detail in the Feasibility Study which is now in progress. (National Highways, Inter-Village and Village Roads are excluded from the project). To assist this work a comprehensive Transport GIS has been built.

Major Components of the GIS

The major components of the GIS are :-

• Road Network
• Towns, Villages
• Public Transport
• Earth Sciences
• Raster Images including Topographical Mapping
• Other

Before looking at each of the above components the choice of software, the method of digitising and the use of handheld GPS are discussed..


Choice of Software  
Some of the reasons, not necessarily in order of importance, for choosing MapInfo were

• its successful application on other similar projects
• SQL processor with string, numerical functions for analysing geographic and non-geographic data.
• Availability of ProViewer a MapInfo facility to provide mapping and information on a CD that can be viewed but not changed.
• Interfaces with MS Office (Excel & Access), AutoCAD, ArcInfo
• Buffer facility
• Facility for heads-up digitising (see below)
• Ability to include photographs (or indeed other raster images in a table)
• Ease of use to refine the digitising of roads etc as the project progresses)
• MapBasic - application language
• Same "feel" as many Windows programs making it easier for senior staff to use.
• Raster image processing
• People, once trained in ArcInfo or AutoCAD, often move jobs to capitalise on their "new" skills

Method of Digitising
The main methods of digitising are

• Using A Digitising Tablet (A0, A1 or A2),
• Heads-Up ie displaying a registered raster image on the computer screen and then using a mouse trace a road or river or to pinpoint the centroid of a village or to pinpoint the location of a bridge or to specify the an area of say a District.
• Manually from map sheets such as the 1:50,000 or 1:250,000 (usually limited to point objects)
• Output from a handheld GPS.(Global Positioning System).

The Department of Earth Sciences, University of Manipur when they have undertaken digitising for us have mostly used an A0 digitising tablet. Tables (layers) digitised in this way were the transport network in NE India and 100 metre contours in the Imphal Valley and surrounding foothills. Before starting the digitising the features - roads, contours are often traced and the tracing sheets placed on the A0 digitising tablet. In this way the information such as contours or rivers from a number of 1:50,000 toposheets can be consolidated on one A0 tracing.

Most of the geographical data in the GIS was generated using the Heads-up Method. A big advantage is that with a notebook this method can be deployed any where - office, home, airport waiting room, in the garden or near the beach. Furthermore every computer in an office can be a "digitising work station". It is also possible to digitise initially by viewing toposheets at say a scale of 1:100,000 to get the GIS up and running and the refine the digitising by viewing at a scale of between 1:25,000 and 1:50,000. Of course the ability to use this method requires maps to be scanned. The valley toposheets have been scanned using large format commercial scanners and the other maps available to us using a Logitech "Freescan" Scanner. Using the latter method toposheets are scanned as three strips. Large hand drawn or annotated blueprints can also be readily scanned.

The information that was initially digitised manually from toposheets were the locations of bridges and culverts - objects were assigned unique identifiers of the form G16.85 ie the 85th bridge/culvert identified on toposheet G16. It must be added that this process also served to familiarise staff to the co-ordinate system.

A hand-held GPS displays X and Y co-ordinates, altitude and trip distance. Whilst out on site the above information (excluding altitude which I have found to be unreliable in any event) can be automatically recorded as waypoints and downloaded back in the office. This method has been used to record the location of photographs - road condition, adjacent land coverage and the precise location of potential quarry sites. It has also been used to convert data such as roughness and strip plans that are recorded on a chainage basis to road links in the GIS. (Another application is to use the tracking facility to record the alignment of say, a road through the hills - the BCEOM team working on the Imphal - Ukhrul Road Project used this facility.)

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