Cadastral surveys in India

Cadastral surveys are specially designed large scale surveys, generally on 1:4000 scale which are linked to land ownership and property. In case of urban cadastral surveys, the scales may be as large as 1:500 to 1:4000. This paper is, however, emphasizing the rural and village properties. The urban cadastre, although very vital needs a separate and detailed discussion.

In practical proportion of the importance, the surveys and mapping oriented activities form only 10% of the total cadastral related work. The remaining 90% really fall in the realm of generating appropriate land records. The importance of these land records is, of course, very high because it is only through the cadastral maps and land records that the owner gets legally linked to his property. This property may be a cultivated field, house or a fishing pond. The fact of the matter is that lack of updating the maps and the land records have given rise to the innumerable court cases. The property related court cases are thriving because of the reduced importance of the cadastral surveys.

Can the modern technology of`Geomatics’ (extended version of surveying and mapping) and the body of knowledge of management of change help in mitigating the major lacunae in the professional practice of cadastral surveys and land records? The answer is emphatic YES. It is with this perspective that this paper has been prepared.

Push From Politicians, Press and Parliament (PPP)

It is a common fact that the present `politics of election’ is centred around the theme of `development’. If development is the `push of the politicians’, the cadastral surveys (and better technology) will become most relevant and urgent. The Government can ill afford to ignore the importance of value adding / improvement in the property related surveys. The fact is that cadastral surveys are the only unique surveys of their kind, which are directly connected with the masses.

If there is development, can cadastral surveys be left behind?

Management of Technological Changes

One has to see the introduction of new technology as an important part of the `change-process’. The change has not only to be `right’ but MISRAshould also be made more `acceptable’ to all the stakeholders of the process. Special thought has, therefore, to be given for bringing lasting changes in cadastral surveys in India.

The scope of this paper is, however, limited to the surveys and mapping technology (ies). The subsequent changes in the area of generating land records is not attempted for want of space.

Historical Perspective of Cadastral Surveys in India

Revenue surveys were initiated by East India Company towards the end of 18th Century primarily to establish the `domain of their influence’ through the collection of revenue from the estates. These estates were rather scattered so only village boundaries were established by the traverse method of surveying. The inside details of properties were left to local surveys. Survey of India as a Department of Government of India, established in 1767, was fully involved in the process till 1904.

Following the recommendation of the 1904 Committee of Government of India, the cadastral surveys were delegated (in my opinion, abdicated!) to the States. The States evolved their

The Management of Change

The change is bound to come due to the application of new technology whose appropriateness is to be proved through reducing cost, producing more village maps in a given time and generating more timely and reliable information. In other words, the new technology has to be:
• Professionally right i.e. follows principle of surveying
• Socially acceptable, by a vast majority of land-owners
• Economically viable i.e. the new technology should be less costly when compared to the past methodology

Example: The new technology may bring some changes in the area of plots which may be less than what is shown on the old map or Field Measurement Book (FMB). The authorities will have to adopt acceptable approach or strategy of gradual change with adequate time interval before new measurements are adopted.

In other words, the changes should not only be `right’ but should also be acceptable.

own legal system of revenue surveys. The Northern States of U.P., M.P., Bengal, Rajasthan, Punjab established ‘graphic output’ of surveys as the legal document whereas the Southern states recognised Field Measurement Book (FMB) as the legal document. There was little input from Survey of India. In 1929, Survey of India took to first aerial survey in Malda district of Bengal which was carried out to produce revenue maps on 16 inches to 1mile scale. But no serious attempt was made to transfer the technology to the States. Again during 1939-1945 war Survey of India adopted air-survey methods and later Photogrammetry in 1954. The situation regarding the technology in the States remained the same as was available in 1904.

Later, in 1964, the first State Cadastral Surveys conference was held in Mussoorie which was motivated by the concept that State Department of Settlement Surveys and Land Records should exchange ideas on the subject to provide technical solutions to, for example, town surveys etc. The conferences have been regularly held but the progress has been rather slow. The author, while serving Survey of India organized a Demonstration Seminar for the technology of Aerial Photography, Photogrammetry, Photo Rectification and Records Management etc in 1973. The Government of India (Ministry of Rural Development) has recently taken up computerization of records and introduction of other relevant technologies quite enthusiastically. This has been motivated, due to the success of Madhya Pradesh in utilizing the aerial photography and rectification process for substituting their plane-table (graphical records), improving their record keeping systems and making the whole system farmer – friendly. This process of technology- transfer from Indian Institute of Remote Sensing, Dehradun to the Commissioner of Land Records, Gwalior has been a successful example
of the transfer of technology.

Meanwhile, new contemporary technologies namely, Global Positioning System (GPS) and Orthophoto Mapping are being harnessed for projects in India. The same technologies could prove very beneficial to the cadastral mapping.

It is suggested that Survey of India should again take the professional lead to `hold-hands’ of States in so far as technological leadership and contributions are concerned.

The Proposed Technology For Cadastral surveys

A cadastral map (or for that matter any map) will generally have the following characteristics:

Geometry (Accuracy of Position) By GPS

The geometry of the map is achieved through use of appropriate instruments. The traditional technology of traversing for establishing ground stations on the periphery of the village revenue map will be replaced by GPS. GPS is very accurate and simple for establishing control points.

GPS technology in `differential mode’ (DGPS) should be employed to accurately fix the `most sacred’ control points i.e. `tri-junctions’ (where boundaries of three or more villages meet).

The main advantage of GPS technology is that ground control stations can be provided even for isolated villages and patches of the area. The technology is not hampered by day / night or weather.

It is recommended that this project i.e. provision of field control should be provided under the supervision of State Government / Government of India in a Public-Private Participation mode. The whole process
should be well documented.

Provision of Heights

In addition, height Bench-marks should be provided on the GPS stations. Presently, no heights are shown on cadastral maps. It is envisaged that heights will have good utility for irrigation projects etc. It is, therefore, recommended that suitable amendments to the present specifications should be made in the State Manuals.

Contents of Cadastral Map-use of Aerial Photography

Traditional methods of creating map-contents have been ground-basedmethods of plane-tabling and / or actual measurements of the plot (followed in Field Measurement Book). These methods have their own shortcoming of inaccuracy etc. But the traditional methods need not be criticized as these have stood the test of time and courts. It is only now that newer technologies are available as replacement of the old technology.

The field methods have been replaced by the aerial photography (Photogrammetry for urban cadastre) and has been extensively used by Madhya Pradesh and some other States. A process known as `Rectification of aerial photography has been adopted by Madhya Pradesh. In this process the positional inaccuracy of land feature is removed. The condition is that the terrain has to be free from major undulations. Technically, rectification removes the distortions due to `tilt’ of aerial photography.

Orthophoto Mapping

Orthophoto is an aerial image (aerial photograph) from where all the distortions, which adversely affect the geometry of the photograph, have been removed. These distortions are due to inherent `tilt’ of aerial photograph and the `relief’ (elevated / undulated terrain) of the objects on the ground. The process of `rectification of aerial photograph practised in Madhya Pradesh suffers because of the errors due to relief. The rectification is, therefore, not recommended for the terrain, which is highly undulated or hilly.

Thus Orthophoto technology will be an acceptable and recommended technology for future cadastral surveys.

The productivity i.e. the reduction of the cost (one third) and increase in production (2 to 3 times) will make this technology soft on budget.

Updating the Cadastral Maps

In view of the legal importance of the cadastral maps which are invariably referred to in matters of compensation for land acquisition etc, the updating is not only necessary but vital. Administratively, this process can be best performed by the persons who are already engaged in the preparation of records. If the original cadastral map has been well supported by GPS and Orthophoto technologies, the updating
of the map becomes quite easy.

The above recommended technological processes lead us to reach to more intense technical discussions. These are motivated primarily due to useful satellite based technologies.

Role of High Resolution Satellite Imagery

Presently two commercial satellites with one-metre resolution are available from USA. The imagery is distributed by National Remote Sensing Agency, Hyderabad. From surveying point of view it should be noted that imagery of 1 metre resolution is able to give a Planimetric accuracy of about 3-4 metres [ 1 ] and that too when one uses the precise (costly) version of the imagery. Therefore, the imagery may not neccesarily be suitable for producing original cadastral records.

This imagery is, however, quite useful in updating 1:4000 scale cadastral records, especially those which have been based on more accurate technology of aerial photography or precise ground methods.

The use of IKONOS, Digital Globe of USA and in future, Cartosat of India has to be appreciated in the light of limitations and effectiveness:

Achievable Accuracies

GPS in differential mode will generally be able to provide accuracies of less than 5 cms to the control points. This is more than adequate for cadastral surveys.Map on 1:4000 Scale Produced by Accurate Ground Method. Considering a point of 0.2 mm on the map of 1:4000 scale, the smallest possible dimension determined on the ground will be:

Aerial Photograph on 1:20000 scale to Produce 1:4000 Scale Cadastral Map – Orthophoto (digital).

Considering accuracy of 20 microns on the negative scale of 1:20000, the smallest dimension on the ground (represented by 1:4000 map scale)

taking into account the other errors due to photogrammetric processes (of aerial triangulation and Digital Terrain Model), the accuracy can be taken as 60 cms.

High Resolution Satellite Imagery 3 to 4 Metres as established by research papers. See references [ 1 ].

Height Accuracy of Aerial Photo 0.1 per thousand feet of flying height; scale 1:20000

Therefore, contours can be drawn at (1.0 x 5) 5 feet, say 2 metres contour interval.

Methodology in Brief

Based on the above discussions, the recommended methodology is given below:Aerial Photography At 1:20000 scale; black and white

GPS Control (Differential GPS) All tri-junctions and some more identifiable
points are controlled. Sketches of the points are made. GPS will provide X, Y and Z coordinates of the points in terms of WGS 84 system. The Z can be ignored as the values are not in terms of spirit levelling procedures.

Photogrammetric Process – Aerial Triangulation and Digital Terrain Model (DTM) After this operations all model / overlaps would have control points. One can resort to Photogrammetry or digital Orthophoto Mapping

Digital Orthophoto Mapping Recognised Orthophoto Mapping software(s) can be utilized to produce images which are true substitute of maps.

Cadastral Records Not all what is shown on an image is relevant. The property / parcel numbers have to be identified on the photo / image by revenue authorities.

Cadastral Map The line-cadastral or digital cadastral map will be prepared after the properties are identified by tracing or digitising.

Ground / Field check by Revenue Officials Revenue officials will make sure that all properties are taken care of attribute information can also be verified and completed at this stage.

Optional Work

• Heights of Objects can be surveyed
• Other information about soil, vegetation etc can also be picked up from photos and verified on ground.

Cost Aspect of the Methodology

The break up of the cost is as follows:

• Aerial Photography The cost depends on the location of the town and its distance from Hyderabad, from where the aircraft commences the flight. As a guide, the cost at Delhi will range from Rs 40 to Rs 50 per hectare.
• GPS control and other field surveys e.g. levelling cost range – about Rs 60 to Rs 70 per hectare.
• Digital Orthophoto Mapping Range …. about Rs 100 to Rs 125 per hectare
• Field / Ground Verification Along without attribute data – Rs 20 to Rs 30 per hectare

Taking the overall cost, it will range from Rs 175 to Rs 200 per hectare. For comparison the cost in a case study of similar nature done in Khamam District of Andhra Pradesh came to Rs 165 per hectare in late nineties.

Recommendations

What is recommended in this paper is the technical aspect of cadastral surveys which is appropriate, modern, acceptable, practical and will provide a big push to the profession of cadastral surveys. The sound base will be given by the technology which eventually will reduce the ambiguity regarding recordsThis technology can be practised in the model o f Public-Private-Participation (PPP). The State Government Departments need not spend huge money in procuring of equipment and instruments.

It is recommended that at initial stages, and in order to increase acceptability of the technology, the job should be done in some selected Taluks as Pilot Project. The technology can be transferred to States after adequate confidence is built up in State Cadastral Organizations. The Survey of India should take a lead role in the introduction of technology,
say, up to establishment of ground control by GPS. The resources generated by private sector in Geomatics can be harnessed through appropriate PPP model.

References

1. Davis, Curt.H; “Planimetric Accuracy of IKONOS, 1 metre Panchromatic Image Products” University of Missouri-Columbia

2. Dikshit, Sanjay; “Integration of Satellite Survey Techniques…..”; Paper in LIS National Conference, Oct 2000 organized by CSDMS, NOIDA.

3. Misra, Prabhakar; “Cadastral Surveys in India A Critique”; Paper in LIS National Conference 2000.

4. Upadhaya, A; “Statewide Digital Data Base and GIS of Cadastral maps, Paper in GIS Development, Dec 2000.