Application of Satellite Images and GIS in the Preparation of Development Plans: Case Study: Master Plan for TUDA Region and Zonal Development Plan for Tirupati Town
Architect – Urban Planner
Project Coordinator at EPC, Ahmedabad
Geographer – Urban Planner
Project Manager at EPC, Ahmedabad
Our urban areas are growing rapidly and therefore need to be planned and adequately serviced to avoid problems associated with unplanned and adhoc growth. Planning so far has been a time consuming activity and by the time a plan is prepared and implemented development continues unabated often defeating the very purpose. A part of the delay can be attributed to the current status of data (outdated maps, lack of information) data collection & analysis and techniques employed to prepare plans. Another aspect with the current methods is that it is not easy to make rational and informed planning decisions. Hence there is need for tools/techniques that enable rapid planning and enable taking rational and informed planning decisions that ultimately lead to plans that are better and implementable. Satellite Images and use of Geographical Information Systems (GIS) are examples of such tools that facilitate preparation of rapid, comprehensive, rational and implementable plans as this paper attempts to highlight through the Case Study of Preparation of Master Plan for TUDA Region and Zonal Development Plan for Tirupati in Andhra Pradesh.
A Mater /Development Plan lays down the basic framework for guiding and regulating future growth. This is done through 3 basic instruments:
The plan preparation process is severely constrained by lack of availability of basic information starting with accurate maps, data pertaining to the land uses, road networks, structures, open spaces, water bodies etc. The city maps have been prepared long ago and have not been updated since then and thus redundant for preparing a city plan. Further most of the secondary information is spread across diverse departments/sources, not updated and the process of procuring it is time consuming. Moreover there is no systematic way of collecting, maintaining and analyzing data/information that may be relevant for planning purposes.
The most crucial information for preparing a Plan is an accurate and updated Base Map of the planning area, road networks, spatial extent of development and the information on the use of each parcel of land. It is the basis for making rational planning decisions. Use of Satellite Images and GIS can fill this gap as is illustrated through the preparation of Master Plan for TUDA Region and Zonal Development Plan.
This paper is divided in three sections –
A Use Satellite Images for Preparation of Base Map
A1 Need for Accurate Base Map for a Development Plan
A Development Plan lays down the framework for future growth, determines the infrastructure development proposals & investments and prescribes the use and development rights for each parcel of land. It is therefore absolutely essential to have a reasonably accurate and updated map to lay the road map for future growth. City Maps are prepared on the basis of maps showing plot details that are obtained from the cadastral maps /Land records available with the District Inspector of Land Records and Revenue Department. These were made during the British times and haven't been systematically updated since then. There are piecemeal changes made by individual plot owners owing to sub division of land or when land is acquired for roads/public projects etc. The information regarding these changes vests with different departments and has not been systematically collated to prepare updated maps. Further new growth and development are not reflected on the maps. Also as these maps are rarely computerized and have been manually traced/replicated over the years, they are even inaccurate geographically. Consequently, they don’t serve contemporary requirements as they are mostly outdated, their generation and maintenance is cumbersome, and they are incompatible with the planning and development requirements of the present times.
However it is not only important to have accurate and up to date Base Maps, but also city maps must be computerized so that layers of information can be attached and spatially represented to support and aid planning decisions. Further, computerization ensures accuracy, makes constant updation easier and makes it possible to view and analyze data at various scales. The first major task in any planning exercise is to prepare an accurate, up to date and computerized Base Map.
A2 Available Methods to Prepare a Base Map for an Urban Area
A geographically accurate Base Map can be generated either by undertaking a detailed topographical survey or by using satellite images along with other sources of information. The salient features and pros and cons of both the methods are briefly described.
A2.1 Topographical Survey
A comprehensive physical survey of the planning area can be carried out using total station survey equipment. Several details can be surveyed ranging from all built features, roads, natural elements, levels etc. This process ensures considerable accuracy however stringent controls have to be ensured while setting the traverse and taking measurements. Such a survey can not only serve the planning objective adequately but also can be later used for detailed planing of infrastructure. Detailed surveys are required while planning and implementing infrastructure works such as roads, drainage, water supply works etc., which need not be repeated. Subsequently the survey information can be used to generate other applications such as assessment of property taxes, mapping of other infrastructure networks for the purpose of maintenance, management, planning etc.
However this requires considerable amount of resources/investments upfront and in most cases wherein the planning agencies don’t have adequate resources a topographical survey is rarely undertaken. Also considerable amount of time is required to carry out a detailed topographical survey especially when there are densely built up areas which is the case with most Indian cities. But this is highly recommended as the investment is justified given the usefulness of such a survey by building centralized databases for all planning agencies, utility agencies etc.
A2.2 Use of Satellite Images
Given the resource constraints, availability of satellite images has made the task of correcting and updating the existing city maps much easier and faster. A reasonably accurate Base Map can be prepared using the satellite images (PAN and IKONOS) as a base and integrating information from various sources such as aerial photographs, revenue maps, SOI sheets, maps from various departments etc. Appropriate corrections are required to ensure geographical accuracy such as geo-referencing and registration of satellite images with topographical sheets. Accuracy can be ensured depending on the resolution of the satellite images used. Certainly the use of such maps is limited as compared to the ones based on topographical surveys.
This methodology has been used for correction and updation of the region and town map of Tirupati Urban Development Authority. The next section describes the process in detail.
A3 Case Study – Preparation of Base Map for TUDA Region and Tirupati Town
Tirupati Urban Development Authority (TUDA), Andhra Pradesh commissioned Environmental Planning Collaborative (EPC) to prepare the Master Plan for TUDA Region and Zonal Development Plan for Tirupati Town in August 2001. The first task was to prepare a Base Map for the entire planning area.
The entire planning area under the jurisdiction of TUDA has an area of 847.95 sq. km., half of which is covered by Reserved Forest. The TUDA area spans across the four mandals of Tirupati Urban, Tirupati Rural, Chandragiri and Renigunta. It includes well developed towns of Tirupati, Tirumala, Renigunta, Tiruchanur, Avilala and Chandragiri - and 85 rural settlements. There is no computerized Base Map for Tirupati Urban Development Authority area or the Tirupati Town area. The existing Base Maps have not been updated since a long time.
Because of the complexities of the issues involved and the availability of data, the Base Map preparation exercise for the entire planning area was divided into two parts.
TUDA Region comprises of 85 villages and 2 urbanized settlements and the Reserved Forest. Individual maps exist for villages. Each village map includes survey plot boundaries, survey numbers, roads and water bodies and drainage channels (major and minor). TUDA has manually traced and combined to form a seamless Base Map for TUDA Region by TUDA. However in the process a lot of detail was lost in terms of plot boundaries and survey numbers. Further the TUDA Region map was digitized and placed on the satellite images. It was found that the map was not geographically accurate. This is evident from the fact that when this map was digitized and the areas was calculated, it did not conform to published revenue area and various features such as roads, railways, water bodies, plot boundaries etc., did not match with those on the satellite image.
Further the map is outdated and does not reflect the recent developments that have occurred. Individual layouts for major developments are available with TUDA (as they have to be submitted for approval). Some of these layouts have been manually incorporated in the Base Maps for TUDA Region and hence the geographical/locational accuracy is questionable.
Tirupati Town comprises of Tirupati Municipal Limit and Tirupati Non Municipal Area (NMA). Tirupati Municipal Limit further comprises of 53 blocks and the Tirupati Village Revenue Area. Individual maps are available for 53 blocks. The block maps show revenue survey numbers, road plots and water body plots. The area within the blocks has Town Survey numbers and area within Tirupati Revenue Village and NMA has revenue survey numbers. There is no other source for the Tirupati Village Revenue area and NMA apart from the existing Town maps.
A seamless map for Tirupati Town has been prepared by combining Tirupati Municipal Corporation and M.R. Palle (NMA). There are two maps available for the Tirupati Town (at different scales) and both do not contain the same degree of information – in terms of roads, survey plots and survey numbers. Hence features from both maps were brought in. The two town maps were digitized and placed on the satellite images. It was found that both maps are not geographically accurate. This is evident from the fact that when these maps were digitized, and the areas were calculated from these maps they do not conform to published revenue areas and various features such as roads, railways, water bodies, plot boundaries etc. do not match with the satellite image.
Further both the maps are quite outdated and do not reflect the recent developments that have occurred. Individual layouts for major developments are available with TUDA (as they have to be submitted for approval). Some of these layouts have been manually incorporated in the Base Maps for Tirupati Town, but again geographical/locational accuracy is questionable.
Features for the Base Map
Before commencing the exercise the features required and their sources were determined and they are as follows:
Key Features of the Process Adopted to Prepare the Base Map
On the basis of the availability of maps for TUDA Region, Tirupati Town, features for the Base map and the availability of other sources of information, a well structured process was adopted for the preparation of the Base Maps. Key features are:
The flow chart illustrates the process of preparation of Base Map for TUDA Region and the various stages are described in detail (Fig No 1a).
The flow chart illustrates the process of preparation of Base Map for TUDA Region and the various stages are described in detail (Fig No 1b).
The next major task in the exercise of preparing a Development Plan is the land use mapping. Usually an extensive physical survey for this task is a must and this process is quite time consuming. Hence for the TUDA Region a preliminary land use map with over 70% of the land use marked was prepared by visual interpretation of the satellite images. Interpretation was based on shape, patterns, textures, location and shades. This was then taken for ground truthing and updated. This considerable saved the time and resulted in a fairly accurate land use map. In case of Tirupati Town a far more detailed break up of land uses was required. The Base Map was superimposed on the IKONOS Image and uses such as open spaces, channels, agricultural areas and water bodies were easily marked. Further using the knowledge of the local officials certain institutional uses and important areas were marked. Then a detailed land use survey was carried out. This process considerably shortened the survey period.
C Use of Satellite Images and GIS to support Planning Decisions
After preparing the Base Map and undertaking the land use survey, a database was developed in GIS environment. This section illustrates the use of the satellite images and GIS to support planning decisions and frame rational proposals.
C1 Developing Land Use Database on GIS
For the built up area in the Town a very detailed and systematic land use survey was carried out. There were various layers of information to be represented such as major land use, land use by floor, intensity of development for each plot and building typologies. A GIS environment was required to reflect and represent such a wide range of information, which was not possible through the Auto CAD software (Fig No 14). Further by attaching a database of varied information to the map, it was possible to carry out several types of spatial analysis, to support land use planning decisions. Moreover in Arc View it is possible to generate areas of major categories and sub category of uses which cannot be done in AUTOCAD (where it is a manual process of calculation and prone to errors).
The various thematic layers that were built were:
The most important application of the satellite images was the mapping of the development sprawl. It gave an indication of the growth directions. It also became evident for the first time that the town of Tirupati had doubled in size and that most of the development was happening outside the municipal limits. The town area is 16 sq km and about 8.5 sq km of development had already occurred outside the municipal limits and another 8 sq km of area is already under layout formation. This has tremendous implications on provision of infrastructure. It is essential to identify an urbanizable zone and plan for infrastructure in this area in the near future to avoid problems of adhoc and unplanned growth.
The various thematic layers that were built were (Fig Nos 16, 17, 18):
Road network planning and proposals are a crucial aspect in a Development Plan. In case of Tirupati town all the minor and major networks were mapped from the satellite images and an updated network was prepared. This formed the basis of evolving a rational structure plan for roads to cater to the future growth. Appropriate hierarchies were delineated and proposals were framed. A road network thus evolved is more implementable.
The satellite images were used for updating the road network in terms of (Fig No 19):
Environmental issues generally are not given sufficient importance while planning for urban areas. TUDA Region has a total of 241 tanks interconnected by water channels. This is fantastic system of natural drainage, which ensures ground water recharge and support the needs for agriculture. Unfortunately this system is getting disrupted as quite a few tanks are getting encroached by development particularly near the town. Tirupati Town had 38 tanks and now only 8 are functional and the remaining have been encroached. While preparing the Development Plan for TUDA Region Tirupati a systematic inventory of all the water bodies was done using the satellite images and topo sheets and various proposals have been framed.
The satellite images were used for (Fig Nos 21, 22):
Environmental Planning Collaborative established in 1996, is a private not for profit, professional planning and development management company incorporated under Section 25 of the Companies Act, 1956. EPC provides professional consultancy services primarily to urban local bodies including Municipal Corporations and Urban Development Authorities. EPC also works with a variety of other agencies involved in urban development such as State Government Departments, International Funding and Lending Agencies, Special Purpose Vehicles for urban development and non-government/autonomous organisations. Most projects are undertaken in a collaborative manner with significant involvement of the client and other related agencies.