CHAPTER - IV METHODOLOGY

Transcription

1 GENERAL CHAPTER - IV METHODOLOGY This chapter describes the methodology adopted in this research. This methodology includes data collection, data preprocessing and image classification using object oriented classification methods. The advantage and disadvantage of this classification method are discussed. There are several types of guidelines for urban design. The first type of guidelines relates to urban design frameworks, development briefs and master plans. Urban design framework mainly consists of two dimensional vision of future infrastructure requirements. Development briefs usually contain a more indicative vision of future development from master plans are detailed plans usually prepared by the Organization that owns the site. The second type of guidelines relates to it, specific topics these usually called design guides cover topics such as fronts, house extensions, lighting and cycling. The third type of guidelines relates to specific policies, such as policies on conservation areas, transport corridors, water fronts and green belts. An established example is the user centered guidelines, which was derived from user specifications and preferences. The fourth type of guidelines relates to a whole local authority area. These may give general urban design guidance for the whole city or country. The development of database for urban design guidelines require resources such as common urban features, like, land coverage, plot size, parking and their guiding regulations, i.e.,

2 47 FAR, set back, land uses, growth space" addition, sections of plots and building heights. The guidelines may provide classification of urban features. The development of urban design guidelines database requires an integrated and multidisciplinary team that understands the importance of quality of urban design. Here, the description about the land cover types and their distributions of the study area is given. Except this, the remote sensing images, ground truth used in this study is described in detail and also the data preprocessing before conducting the classification is described. 4.2 DATA PRODUCTS USED Depending on the availability of maps for the study area, features for the Base Map and availability of other sources of such data products are derived and extracted through various sources which are given in the following table 4.1,4.2 and Fig 4.1. Table 4.1 Shows Data Sources Type of Data Toposheets (1:50,000 Scale) Satellite Data (IRS ID, LISS III of IRS 1D Census data Meteorological Data Maps showing Existing information of Hyderabad and its boundary of MCH area Software used Autocad, ArcInfo, ArcView, ArcGIS 9.1, Erdas 8.6 Field Data Source of Data SOI (Survey of India), Government of india. NRSC (National Remote Sensing Centre) Bureau of Economics and Statistics (BES), Hyderabad Indian Meteorological Department (IMD) Municipal Corporation of Hyderabad (MCH) Centre for Environment, JNTUH. APPCB APSRAC Licensed Versions from ESRI New Delhi Through intensive field work (Ground truth)

3 48 Table 4.2 Data Type, Important Features and Sources of Acquisition S No. Data Type Features Source of acquisition Use of the data I Thematic Data 1 Land use / Built-up land, Toposheets of Survey of To prepare urban land use Land cover agricultural land, Water bodies, BSA, land with shrub, land without India. State Forest Department. maps in order to decide the future land management, suitability shrub, single and double Satellite data from and allocation proposals crop, plantations etc. NRSA for any given town to meet the growing needs. Also helps to identify the future growth direction and also to conserve and protect the sensitive locations. To assess the land use & land cover in different periods of time. 2 Geomorph ology Pediplain-Inselberg complex, Pediplain with moderate weathering, Pediplain with shallow weathering, Residual hill, Pediment, Alluvial plain, Valley fill etc. Satellite data + SOI Toposheet To understand the genetic origin of the landforms. To delineate the physiographic details useful for urban applications. To identify certain topographical and terrain details such as relative topographic variations, hill boundary, drainage pattern and plateaus etc. Structural landforms can be identified with the associated data interpreted form satellite data. 3 Geology Granite, Pegmatite, AAG, Hyderabad quadrangle To prepare geo data base AMG, AT etc. map from Geological for structures

4 49 Survey of India, Hyderabad 4 Structures Conformed lineaments, Inferred lineaments, faults etc. Hyderabad quadrangle map and Satellite data 5 Soil Clay, gravelly clay, Satellite data + Land gravelly loamy etc. use and Soil Survey Department II Topographic Data 1 Base map Rivers/water bodies, Toposheets of Survey of major roads, railways. India. 2 Drainage map Drainage pattern, rivers, tanks Toposheets of Survey of India updated using the satellite data 3 Transporta Major settlements. major Survey of India tion roads and minor roads Toposheet Network map 4 Watershed Watersheds, drainage Survey of India map pattern, major water Toposheet bodies 5 Slope map Slope classes 1 to 6 Survey of India Toposheet To perceive the spatial continuity of the structures in the areas under thematic mapping. To prepare Soil Map which allows exploiting the inherent relationship between soil and the landscape and this will make it possible to understand nature and distribution of different soil types. To understand the administrative boundary of various administrative units and also to identify various types of water bodies, different categories and grades of roads and railways. To prepare the drainage network map and catchment area maps. To identify and map various types road network and also includes bus terminals, airport, railway station and truck terminals. To identify various types drainage network and identify the watersheds and catchment areas. To prepare a contour map and to identify the levels

5 50 and undulations of the ground. III Data derived from other thematic and topographic maps 1 Physiograp hy Hills, Undulating land and plains Survey of India Toposheet To prepare a contour map and to identify the levels and undulations of the ground. 2 GW Potential map Classification into high, medium and low based on yield/availability Satellite data To identify and map the ground water availability map and thereby identify the potentiality of yield. 3 GW table map High, medium and low zones depending on depth of water table Central/State Ground Water Board To identify and map the ground water availability map and thereby identify the potentiality of yield. 4 Infiltration rate map High, medium and low zones depending on infiltration rate Soil map, agriculture department, infiltration, geomorphology map To prepare infiltration rate map. IV Collateral Data 1 Demograp hic data Population density Bureau of Economics and Statistics Division To identify the distribution, density, growth of population for different locations and for different periods. 2 Rainfall Data Rainfall Bureau of Economics and Statistics Division To prepare the map showing the rainfall distribution during different periods and at different locations. 3 Existing ground water quality Ground water quality Central Ground Water Board, State Ground water Department and APPCB To map the ground water quality map useful for planning various developments data 4 Existing Air quality data Air quality APPCB To prepare the pollution level maps for different periods and for various locations.

6 51 Figure 4.1 Flow chart showing the methods of collecting data in GIS 4.3 GIS DATA TYPES Basically all the GIS data used in this study are classified as Topographical data Thematic data Collateral data The topographical and thematic data are classified as spatial data and the collateral data as attribute data. The details of these types of data products are discussed below. 4.4 SPATIAL DATA The spatial data consists of topographic, thematic and other derivative maps derived from satellite sensing system and SOI toposheets. The

7 52 satellite sensors are Panchromatic (PAN) and LISS-III (Linear Imaging Self Scanner) sensors of IRS-ID satellite, SOI toposheet series are 56K/1 to 56K/16 on 1:50,000 scale. The step-by-step procedure for preparing the spatial data for the entire study area is given in Fig. 4.1 and is discussed below. Step 1: Satellite data processing using image-processing software like ERDAS (Earth Resource Development Application System) and EASI/PACE (EASI - Environmental Analysis and Scientific Interface, PACE Programming language) and hardcopy generation Step 2: Generation of thematic maps viz., land use / land cover, geomorphology, geology, groundwater prospects etc by visual interpretation of satellite imagery and SOI toposheets. Step 3: Generation of topographical maps showing physical characteristics of the study area. The topographical maps extracted from SOI toposheets are base, road network, drainage, watershed, slope and physiography. Step 4: Generation of maps derived from other thematic and topographic maps. Step 5: Scanning and digitization of the thematic, topographic and other derivative maps Step 6: Digital spatial database generation using ARC/INFO and Arc View GIS software Satellite Data Processing The second generation operational Indian Remote Sensing IRS-ID satellite was launched in the year 1998 by the indigenously developed

8 53 Polar Satellite Launch Vehicle (PSLV) from Sriharikota, India. This satellite is placed in a near circular, sun-synchronous, near polar orbit with nominal inclination of at a mean attitude of 780 Km. There are three sensors on-board this satellite, namely 1) Panchromatic Camera (PAN) 2) Linear Imaging Self Scanning Sensor (LISS III) 3) Wide Field Sensor (WiFS) (Anji Reddy, 2001). In this study, digital remote sensing data of LISS III and PAN of IRS ID obtained from NRSC is used. Therefore, it is more appropriate to give the sensor characteristics of LISS III and PAN (Table 4.3). Base map on 1:50,000 scale obtained from SOI toposheets covering the entire study area is used to extract the Ground Control Points (GCPs) and to demarcate the boundary of study area on imagery. This information is then used for image registration of LISS III and PAN digitally using ERDAS image processing software. Table 4.3 Sensor Characteristics of IRS ID (LISS III and PAN) Sensor Sensor Characteristics LISS III PAN Spatial Resolution 23.5 m 5.8 m Spectral Resolution 4 1 Radiometric 6 6 Resolution Swath width Geo-coding and Geo-referencing The following standard techniques employing ERDAS Image Processing software have been adopted for Geo-referencing of LISS III and PAN data covering the study area. Toposheets covering the entire

9 54 study area on 1:50,000 scale are scanned and raster file is created. These are further geo-referenced based on the longitudinal & latitudinal co-ordinates. After geo-referencing all the maps are edgematched and a digital mosaic is prepared which depicts the continuity of the study area. The LISS III data obtained from NRSC is processed for initial corrections like drop outs, stripping and earth rotations. Sufficient number of well-distributed ground control points are selected both on the toposheet and corresponding imagery. Care is taken to satisfy the condition on density of GCPs for image registration. Geo-referencing is carried out using ERDAS image processing software. The georeferenced image is further mosaicked and then feature matching is carried out. Similar procedure is applied for PAN data. At the end of this process the digital data free from all distortions is available for digital image enhancement and thematic map preparation with the help of visual image analysis techniques Digital Image Enhancement of LISS III data Image enhancement procedures are applied to image data in order to more effectively display or record the data for subsequent visual interpretation. Image enhancement deals with the techniques for increasing the visual distinctions between features in a scene (Lillesand and Keifer, 2000). The goal of spectral enhancement is to make certain features more visible in an image by bringing out more contrast. Initial display of LISS III data through ERDAS software revealed that the features like minor roads, streams and river are not

10 55 clear / visible as the contrast of the image is very dull because the raw data values fall within a narrow range. Therefore, an attempt is made to apply linear contrast stretch technique in order to improve the contrast of the image, which can be capable of expanding the dynamic range of radiometric resolution of LISS III digital data. To perform this technique, Look up Table (LUT) is created that convert the range of data values to the maximum range of the display device. Based on these LUT s an enhanced image is produced Merging of LISS-III and PAN data of IRS-ID In order to increase the efficiency of feature extraction, LISS-III (4 band, 23.5m spatial resolution, colored data) and PAN (single band, 5.8m spatial resolution, black and white data) data are merged in ERDAS image processing software to obtain a fused data product having 5.8m spatial resolution of PAN data and color from LISS-III data (Fig. 4.2). A hardcopy of this fused satellite imagery is generated for subsequent analysis which helps in better visual interpretation to extract the thematic data by applying pre-visual interpretation, ground truthing and post visual interpretation techniques Generation of Thematic Maps The thematic maps namely, land use/land cover, geomorphology, geology, groundwater prospects map and soil are generated from hardcopy of the satellite digital data. The standard basic elements and key elements for visual interpretation are applied on the satellite hardcopy image so as to extract the entropy or information content in accordance with the above thematic maps. At the end of the

11 56 interpretation process, the above paper based thematic maps are ready for subsequent scanning and automated digitization for creation of a digital database for GIS data analysis and modeling Generation of Topographic Maps Creating a GIS spatial database is a complex operation, which involves data capture, verification and structuring processes. Raw geographical data are available in many different analogue and digital forms such as toposheets, aerial photographs, satellite imageries and tables. Out of all these sources, the source of toposheet is of much concern to natural resource scientist and an environmentalist. In the present study, the base layers generated from toposheet are, (i) (ii) (iii) (iv) (v) (vi) Base map Drainage map Transportation Network map Watershed map Slope map Physiography map These paper-based maps are then converted to digital mode using scanning and automated digitization process. These maps are prepared to a certain scale and show the attributes of entities by different symbols or coloring. The location of entities on the earth s surface is then specified by means of an agreed co-ordinate system. It is mandatory that all spatial data in GIS are located with respect to a frame of reference. For most GIS, the common frame of reference coordinate system is that of plane, orthogonal cartesian co-ordinates

12 57 oriented conventionally North-South and East-West. This entire process is called geo-referencing. The same procedure is also applied on remote sensing data before it is used to prepare thematic maps from satellite data Derived Thematic Maps Although using remote sensing satellite data and survey of India toposheets for making thematic maps as well as topographical maps is very attractive, serious attention is paid to develop maps showing, (i) (ii) (iii) (iv) (v) Ground water potential Ground water table Infiltration rate Ground water quality Air quality The first three maps are derived from hydro-geo-morphological characteristics and the groundwater quality and air quality maps are prepared from collateral data collected from various related organizations. 4.5 Attribute Data The attribute data in the present study consists of collateral data, which includes demographic details, solid waste generation rates, ground water levels, water quality data and air quality data acquired from various Government organizations like Andhra Pradesh Pollution Control Board (APPCB), Central Ground Water Board (CGWB), Bureau of Economics and Statistics (BES) etc. 4.6 Requirements Study Phase:

13 58 In this phase, it is required to finalize the scope of work and identify the customization needs for the study area of Hyderabad and also for the components which are related to urban planning and management. The full scope of work is documented as the Software Requirements Study (SRS) Designing Phase: This will include the details of the interface, database and the software developmental issues. i Development and Unit Testing: Based on the design, the development work will be taken up for preparing the database and the interface. This will be followed by the testing. ii. Implementation: After preliminary testing it will be followed by the implementation and testing and if any modifications are required the same will be incorporated and final system will be installed. iii. The Modules being proposed in the GIS Solution are 1. GIS based modules 2. Non-GIS based modules MIS iv. The GIS based Modules would cater to a. Property Tax b. Municipal Properties c. Solid Waste Management d. Storm Water Network

14 59 e. Drainage Network f. Road Network a. Property Tax In this module, it would be possible to generate the following On Click Thematics on the Property, Sub Locality, Locality, Ward and Circle. Property Map i. Land use (Open Spaces, parks, play grounds) ii. iii. Assessment workflow based. Property Taxation. Property Tax Assessment Collection Arrears Defaulters. iv. Commercial Permits and Taxes v. Floor wise Land use vi. vii. Excluded Properties. User defined queries. Sub Locality, Locality, Ward and Circle Maps 1. Assessment Assessed and Non assessed 2. Property Tax 3. Bills Sent 4. Collection 5. Arrears

15 60 6. Defaulters 7. Registration Taxes 8. Commercial Licenses 9. User Defined Queries. b. Municipal Properties In this module, it would be possible to generate the following On Click Thematics 1. Based on the Rent / Lease 2. Land use 3. Maintenance schedules 4. Green zones (trees, parks, etc.) (Open spaces, Parks, play grounds). c. Solid Waste Management In this module, it would be possible to generate the following On Click Thematics 1. Types of Bins 2. Types of Collection methods (hand cart, truck, door to door, paid collection) 3. Dumping Grounds 4. Shortest Route Analysis for Garbage Collection d. Storm Water Network In this module, it would be possible to generate the following On Click Thematics i Type of pipe sizes ii Types of Connectors (T, etc.,)

16 61 iii Type of water flow regulation iv Maintenance schedules: working, non working, closed. e. Drainage Network In this module, it would be possible to generate the following On Click Thematics 1. Type of drainage (L, channel, open, closed) 2. Types of Connections 3. Manholes 4. Type of water flow regulation 5. Maintenance schedules: working, non working, closed. 6. Encroachments having the decision support model for nalas and storm water drainage system. f. Road Network In this module, it would be possible to generate the following On Click Thematics 1. Type of roads (Main, by-lanes, etc) 2. Types of Connections (traffic islands, etc.,) 3. Type of traffic flow (one way, two way with barriers) 4. Pavements 5. Maintenance schedules: working, non working, closed. 6. Encroachments having the decision support model for road widening. g. Non-GIS based modules MIS i Assessment of Property

17 62 ii Billing application for Property Tax, Registration Fees and Commercial Permits. The proposed solution would have the capability for linkages with other user departments as stamps and registration, telecom, postal, police, water supply, AP Transco etc. For this purpose a common identification number would have to be selected in conjunction with MCH and the other user departments. h. Building Approvals: Any new building approval can be added to the GIS. Any modifications to the building, i.e. addition of new floor / apartment, modification of the buildings in the dimension, or the use, the approval is required. This is available in the solution. Also building plans, as scanned images can be stored in the GIS and can be viewed any time. Even the old plans can also be viewed. Plans submitted for approval and plans approved can be retrieved. i. Trade Licenses: Food Licenses, Trade Licenses, Entertainment Licenses, etc., are stored in the GIS and are available as thematics. Thematics can be prepared based on the validity of the licenses i.e. licenses valid or expired. 4.7 WORK STAGES The objective of this study is to develop a detailed large scale map and to create computerized user interactive conceptual model for urban activities based thematic maps in an integrated GIS environment. The

18 63 various physical features of study area have to be considered to ensure adequacy of planning to meet multitude of objectives. This requires an understanding of the complete ground situation of various physical spatial features, facilities and the socioeconomic parameters of the study area by conducting a comprehensive field survey. Details of Works involved: The following stages of work are involved in the present project work. Preparation of Base map Field Survey Digitization of surveyed map Generation of themes Integrated application development. 4.8 DATA PROCESSING The project is executed through the following steps a) Acquisition of satellite data from NRSC, Balanagar, Hyderabad and toposheet from survey of India (SOI), Hyderabad. b) Geocoding and Georeferencing of LISS III and PAN digital data by extracting the Ground Control (GCPs) from SOI toposheet c) Digital Image enhancement and application of correction models for making the digital data free from error and distortions in terms of radiometry and geometry of the satellite data. d) Fusion of PAN and LISS III for merged product preparation of a mosaic. This is FCC mode and is used for visual interpretation

19 64 to extract the land use/land cover information by applying both previsual interpretation ground truthing and post visual interpretation of this image mosaic. e) Preparation of cartographic output for making the data layer ready for scanning for further GIS analysis. f) Scanning of cartographic output using Ao scanner, digitized data compatible to ARC/INFO GIS software. g) GIS data manipulation and analysis, linking the spatial data file and attribute data file for the creation of topology. h) GIS output in the form of land use/land cover map showing various land use/land cover patterns of MCH jurisdiction. i) Overlay of major road network on the land use/land cover map for the final project as required by MCH administration.

20 65 Data Capture Creation of Database using satellite data Creation of Database using existing Maps IRS 1C LISS III and PAN data Transformation of GCP on Digital image, Registration and Georeferecncing of satellite digital data. Survey of India Toposheets Zonal Maps from MCH Scanning and Digitization of all maps State Road Network Maps Preparation of PAN and LISS Fuged Data Using EASI/PACE Software Editing of all scanned Data using Auto CAD, ARC-INFO Softwares Preparation of Base Map Using SOI Toposheets Preparation of Pre-Field Visual Interpretation of Land Use/land cover map Field work for collecting Ground Truth Data Preparation of Final Land Use/Land cover Map Preparation of Zone wise Maps Identification of GCPs from Maps of SOI Zone wise Preparation of Zone wise Fuged Satellite Data Using EASI/PACE Software Preparation of Overlay map of Road Network and Satellite Data Preparation of Softcopy of Land Use/ Land cover, using ARC-Info Software Quality check with field data Plot File/Print Out of the Land Use/Land Cover Map Preparation of Plot File Soft Copy GIS Product Generation Figure 4.2 Flow chart showing the methodology for urban GIS data processing