Use of large-scale cadastral maps
Preparation and use of large-scale maps, especially for rural areas, is not as good as in developed and other developing countries (Rudraiah). Maps are required by many department, NGOs, agencies, companies to carry out developmental activities in the area. Local authorities, public undertakings, service organisation require maps. However, the requirement of maps in terms of quantity, quality and accuracy vary from organisation to organisation. It is important to note that all the agencies aforementioned and others do not need comprehensive map, i.e. all the information in map.
Need For Computerised Village Maps
Cartographers use methods of showing objects on maps in various ways- for example symbols or objects, lines, hatching boundaries etc. Usually separate maps are created for different subjects or themes, thus, giving rise to numerous maps of the same area. Since in most cases these maps are produced by different agencies using no common methodology, the scales of these maps are also quite different. Computerised maps comes very handy for these initial stages of mapping and prove much more useful when mapped data is put to use. Computerised maps allow mapping of details and minor alterations wherever required. The selected superimposition of selected themes gives idea of an integrated picture and helps to understand area by considering variety of features together.
Lacunae in Existing Cadastral Maps
Exhaustive information is available but hardly used. The information collected from the revenue departments is exhaustive but not used at par. This ignores the logical information principle that as far as possible collection of information should be avoided if it is not going to be used. Further, a number of registers need to be unnecessarily maintaining the auxiliary information. Hard print cadastral maps are not easily available for planning process and area away from the reach of common people. Such maps are only the property of government authority and are used as desired by them.
Development in Digital Cartography
The move towards automation has necessitated some redesigning of maps by eliminating some content (Hadley, 1987) and modifications of others like the conventional hatching replaced by coloured filling of specific symbol.
Simplification of information and graphic design are often undertaken simultaneously in manual generalisation, in digital cartography there is a need to distinguish between information generalisation and display generalisation; the former contributes to digital mapping, the latter to visual mapping. Both types of transformations are intellectually demanding and involve a variety of subtasks and processes. Many applications use maps of the same entities compiled at a variety of scales with different content and symbolism. Many land information systems focus on the land parcel and are concerned with the areal extent of such linear objects. A number of users, such as in local government and NGOs, need both detailed and simplified representations of the same objects. At present, scale-related requirements are met by multiple definitions of the same areas. The scale of display appropriate for each feature is also recorded within a scale-integrated database. Systems based on raster/video images zoom by retrieving images captured at the next larger scale. Other researchers are manually integrating road networks captured at different scales for route planning and are investigating database designs for supporting scale-free mapping (Abraham, 1989). The digital mapping has completely transformed cartography since the mid 1980s where map output in fast multiple reproduction made easier.
Methodology
Monitoring is exercised to make a definite assessment of results of actions and activities and there by decide if any change required. Monitoring through digital maps is very effective and useful. By pointing initial and current status on maps the impact area may be easily seen. Creating maps, union, intersection, subtraction and analyses are easily carried out.
Computerization: There is a considerable effort in culling out the information from the registers to prepare reports in the current manual system. The load of processing/calculation is currently placed on lower staff to maintain documents. The objective is to map out land parcel wise basic indicators / vital statistics. It is envisaged that all data would be computerised and presented in a visual form on a digitised map.
After the initial exercise, including necessary amendments to methodology; it is decided to undertake the task for cadastral mapping. The mapping involved the following two processes being undertaken simultaneously:
- Computerised digitization of maps
- Data collection and updation.
Both processes converged once they were individually completed - i.e. the land parcel-wise data was entered into tabular fields that were linked to each land parcel on the digital map.
Computerised digitization of maps and data is undertaken using cadastral maps basic data like land parcel size, ownership, landuse, cropping pattern and infrastructure details obtained from the “Patwari” as a base. Basic physical features, boundaries and important landmarks were digitized. Other primary baseline and temporal data collected entered in computer system the formulate database.
Cadastral Mapping
Village Khasra (Cadastral) map is very vital and important because it carries the smallest ever mapped land unit in it. The villagers use the maps for general observation at village level and useful for macro level application. Cadastral maps are generally available on 1:6000 or 1:4000 scales. The cadastral maps are consists of all three types of geometries, i.e. point, line and area (polygon). In GIS based cadastral maps all the characteristics like geometry, attribute and map objects are present.