3.2 Case study
3.2.2 Data collection and generation required for model development of the study area
For the study area, although historical urban settlement data can be derived from satellite images, the other sets of data like land values, numbers of commercial units, etc., are not available for sufficient numbers of years. On the contrary, due to the availability of all aspects of data in the recent census year 2011, the model has been formed with spatially variable data of the year 2011 with respect to 15 hills of Guwahati city.
Fig. 3.3: Location of Guwahati city in India (Source: GMC)
3.2.2.1 Determination of urban settlement in hills and free spaces available in AOI A Linear Imaging Self Scanning Sensor (LISS)-IV satellite image of 5.8 m resolution (capture date: 11 November 2011) was used for this purpose. Processing of the multispectral image has been performed in ERDAS Imagine (2014 version) platform.
The image consists of three bands: band 4 (near infrared), band 3 (red) and band 2 (green). These three bands are stacked and a false colour composite is generated in the software where the data collected in band 4, band 3 and band 2 are displayed through the colour red, green and blue, respectively. To have good and distinct visual appearance of the inbuilt geo-referenced image, the brightness and contrast enhancement, atmospheric correction etc. were carried out. Again, the geographic information related tasks such as edition, storage, handling or management of spatial database etc. are executed in ArcGIS-9.3 software. Based on visual interpretations i.e.
depending on their unique texture, shape and tone, the urban settlements, hills and various excluding areas like the river, lake, zoo, etc., are outlined from the image in ArcGIS-9.3. Delineated objects were also checked in high-resolution Google Earth view (imagery date: 31 December 2011). Since the study area (GMCA) has no distinct division based on social and geographical condition, the Euclidian allocation has been
used to assign AOI to every hill. The location of the hills and their AOI in the LISS-IV image of the study area are shown in Fig. 3.4.
(i)
(ii)
Fig. 3.4: (i) Scene of Euclidean allocation (ii) Outlines of the hills (yellow) and AOIs (black line)
N
N
Till 2011, 28.43% of total area of Guwahati Municipal Corporation Area (GMCA) was found to have urban settlements. One important point is that out of the total area of Japorigog hill (9.65 sq. km), an area of 1.57 sq. km is covered by state zoo, which does not have the probability of having urban settlements in future. So, for Japorigog hill, urban settlement till 2011 has been expressed in terms of net hill area (excluding state zoo area). Finally, free space available in AOI of every hill is calculated by using Eq. (3.1) and is shown in Table 3.1.
Table 3.1: Urban settlement in hill and free space available in AOI in 2011
Hill ID
Hill name Hill area (sq. km)
Urban settlement in hill, till 2011 (in % of hill area)
AOI (sq km)
Urban settlement in AOI, till 2011 (sq. km)
Excluding area (sq. km)
Net AOI (sq. km)
*1Free space in AOI in 2011 (%), Af
1 University 2.10 7.85 13.34 1.98 2.95 10.39 80.91
2 Fatasil 15.91 12.47 22.07 6.51 1.77 20.30 67.93
3 Kalapahar 1.98 18.56 6.25 3.12 0.09 6.16 49.30
4 Sonaighuli 0.36 16.54 4.08 0.85 0.04 4.04 78.86
5 Sarania 0.34 28.31 3.62 2.30 0.10 3.52 34.63
6 Kharguli 6.54 25.87 5.26 2.63 0.21 5.05 47.95
7 Japorigog 9.65 17.49 13.14 5.97 0.87 12.26 51.35
8 Burhagosain 2.01 5.70 4.31 0.80 0.00 4.31 81.41
9 Khanapara 6.63 6.44 5.19 1.23 0.07 5.13 76.00
10 Garbhanga 0.95 8.21 2.20 0.73 0.04 2.17 66.30
11 Kamakhya 3.05 22.63 3.16 1.54 0.05 3.11 50.41
12 Kahilipara 6.62 20.91 12.97 8.43 0.34 12.62 33.24
13 Betkuchi 0.24 14.36 5.01 1.42 0.23 4.78 70.37
14 Chunsali 8.93 6.82 2.69 0.64 0.03 2.66 76.06
15 Koinadhara 2.22 14.03 6.93 3.26 0.09 6.84 52.39
*1Free space available in 2011 in AOI is expressed in % of net AOI.
3.2.2.2 Calculation of average slope and average elevation of hills
A slope map is prepared from Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) of 1 arc-second resolution (downloaded from USGS earth explorer) in ArcGIS 9.3. Then, average elevation and slope for every hill are obtained by inputting the DEM and the slope map of the study area to the ‘‘zonal statistics as table tool’’ of ArcGIS 9.3. The DEM and the slope map of the study area are shown in Fig. 3.5 and Fig. 3.6, respectively. The average slope and elevation of individual hill are shown in Table 3.2.
Fig. 3.5: DEM of the study area.
Fig. 3.6: Slope map of the study area
Table 3.2: Average elevation and average slope of hills
Hill ID. Name of hills
Average slope (degree), G1
Average elevation (m), G2
1 University 13.78 90.85
2 Fatasil 12.96 127.72
3 Kalapahar 9.74 90.59
4 Sonaighuli 11.62 77.86
5 Sarania 19.68 99.35
6 Kharguli 10.94 98.91
7 Japorigog 13.76 119.13
8 Burhagosain 13.67 108.01
9 Khanapara 14.11 153.21
10 Garbhanga 10.97 88.60
11 Kamakhya 18.68 137.05
12 Kahilipara 13.12 118.37
13 Betkuchi 10.98 76.81
14 Chunsali 12.84 117.39
15 Koinadhara 10.57 85.03
3.2.2.3 Calculation of commercial unit density in AOI of hill
Numbers of commercial buildings lying in every ward of GMCA for the census year 2011 were collected from Property Tax Division of GMC. Different wards are contributing different amount of areas to AOIs of hills. Hence, numbers of commercial units in every AOI are calculated based on the percentage of ward area shared by an AOI. Fig. 3.7 shows the wards lying in the AOIs of the hills of Guwahati city. The calculated commercial unit densities (numbers of commercial units per unit AOI) are shown in Table 3.3.
: AOI boundary : Serial numbers of AOI : GMC ward Fig. 3.7: GMC wards lying in areas influence of hills Table 3.3: Commercial unit density (2011) in AOIs of hills
Hill ID.
Name of hills
Numbers of commercial units (2011)
AOI (sq km)
Commercial unit density (numbers/sq km), Cu
1 University 419 13.34 31.39
2 Fatasil 3953 22.07 179.09
3 Kalapahar 966 6.25 154.55
4 Sonaighuli 743 4.08 182.34
5 Sarania 851 3.62 234.94
6 Kharguli 1956 5.26 371.81
7 Japorigog 890 13.14 67.77
8 Burhagosain 148 4.31 34.34
9 Khanapara 267 5.19 51.35
10 Garbhanga 267 2.20 121.26
11 Kamakhya 377 3.16 119.34
12 Kahilipara 2909 12.97 224.33
13 Betkuchi 533 5.01 106.31
14 Chunsali 26 2.69 9.49
15 Koinadhara 611 6.93 88.24
3.2.2.4 Determination of land value in the AOI of a hill
Lists of land values of Guwahati city for the census year 2011 were collected from Revenue Branch of Kamrup Metropolitan district. In these lists, the land value of a
locality within an AOI varies depending on its distance from main roads. An average land value has been determined for every AOI based on area-weighted method. In the official list, land values have been expressed in a unit of 'bigha'. In Assam, 1 bigha is equal to 1340 m2. Here, the calculated average land values have been expressed in square metre. These are displayed in Table 3.4.
Table 3.4: Land value (2011) in AOIs of hills
Hill ID. Name of hills Land Value (Rs/Bigha) (2011) Land Value (Rs/sq m), Lv
1 University 4167000 3109.70
2 Fatasil 5535750 4131.16
3 Kalapahar 8085000 6033.58
4 Sonaighuli 7000000 5223.88
5 Sarania 15800000 11791.04
6 Kharguli 13965000 10421.64
7 Japorigog 8060000 6014.93
8 Burhagosain 2475000 1847.01
9 Khanapara 4950000 3694.03
10 Garbhanga 6200000 4626.87
11 Kamakhya 12220000 9119.40
12 Kahilipara 11835000 8832.09
13 Betkuchi 6760000 5044.78
14 Chunsali 3200000 2388.06
15 Koinadhara 6720000 5014.93
3.2.2.5 Assignment of favouring index to AOI
Names of the major educational institutes (Govt./provincialised) are taken from Directorate of Higher Education and Directorate of Technical Education, Govt. of Assam. On the other hand, tourist places and economically active areas are obtained from the master plan of Guwahati Metropolitan area-2025 (GMDA 2009). For the study area, no statistical data are available on the contribution of components of favouring index on increasing urban settlement. Hence, an expert opinion survey has been conducted among the urban planners and other stakeholders who are closely related to the city development programs and have knowledge on historical growth of the city.
Through this survey, weights to every component of ‘‘F’’ have been applied on a scale of 0–1. Based on their view on the role of every institute of an AOI on increasing settlement in its corresponding hills, experts were asked to categorize the educational institutes into two classes—significant level and average level. AOI of Sarania and Kahilipara hills, having the highest numbers of higher educational institutes (2
significant and 5 average levels), gets the highest weight (=1). Next, AOI of university hill which contains 3 significant institutes acquires the second highest weight (=0.6).
Accordingly, weights applied to every average and significant level institute is obtained as 0.12 and 0.2, respectively. Similarly, Kamakhya temple, located on the top of the Kamakhya hill, is the most prominent tourist place in Guwahati, and hence, it gets the highest weight (=1) in the expert opinion survey. Weights to the other tourist places were assigned by experts based on the role of tourist places on providing job/business opportunities and growing developmental activities in the neighbouring area.
Depending on the degree of economic activeness, weights have been applied by the experts to these places. On the other hand, weights for the location of the hill with respect to the core city area have been assigned based on the percentage of AOI lying within the core city area. Here, the old municipal area of Guwahati city has been considered as the core city area. Finally, ‘‘F’’ for every hill is calculated by taking the average of the weights given to all of the four components. These values are displayed in Table 3.5.
Table 3.5: Favouring indices for hills of Guwahati city
Hill ID. Name of hills
Total weight for educational
facilities in AOI of hill
Weight for Major tourist places in
AOI
Weight indicating
present economic activities in
AOI
Weight indicating Location of hill in heart
of city
Favouring index, F
1 University 0.60 0.35 0.00 0.00 0.24
2 Fatasil 0.36 0.00 0.40 0.30 0.27
3 Kalapahar 0.00 0.00 1.00 0.70 0.43
4 Sonaighuli 0.00 0.00 0.30 0.00 0.08
5 Sarania 1.00 0.20 1.00 1.00 0.80
6 Kharguli 0.40 0.90 0.90 1.00 0.80
7 Japorigog 0.00 1.00 0.40 0.30 0.43
8 Burhagosain 0.00 0.00 0.00 0.00 0.00
9 Khanapara 0.00 0.60 0.00 0.00 0.15
10 Garbhanga 0.00 0.30 0.00 0.00 0.08
11 Kamakhya 0.24 1.00 1.00 0.80 0.76
12 Kahilipara 1.00 0.00 1.00 1.00 0.75
13 Betkuchi 0.00 0.00 0.90 0.00 0.23
14 Chunsali 0.00 0.00 0.00 0.00 0.00
15 Koinadhara 0.40 0.00 0.80 0.00 0.30