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Web GIS for Decentralized District Planning :
A Case on Cuddalore & Nagapattinam Districts of Tamil Nadu
http://www.tngis.tn.gov.in
National Informatics Centre, Chennai
Introduction :
 Geographic Information System (GIS) has become an
important tool for managing, analyzing and decision
making, by seamlessly combining both spatial and
non-spatial data.
 In Tamil Nadu, a vast volume of spatial data sets have
been generated through GIS projects undertaken by
several departments and agencies.
 The present challenge is to integrate and coordinate
these varied and disparate efforts to build a GIS
structure for the state as a whole.
 The present project at Cuddalore and Nagapattinam
is a first step towards this larger objective of building
TNGIS.
Basic Issues :
 Need for data/information in decision making
 Huge volume of existing data sets in various departments are
underutilized/unutilized
 Sourcewise variation leads to spatial
information and mismatch in boundaries
/
location
inaccuracy
of
 Varied Data formats and its interoperability
 Proprietary Vs. Opensource Tools in Managing the Spatial and Nonspatial Information
 Data update over time
 Capacity Building in District
 Integration with the National Spatial Data Infrastructure (NSDI)
 Intranet Vs Internet based solutions
 Wider dissemination
Approach and Methodology :
 The major challenge is to integrate and coordinate these varied and
disparate efforts to build a GIS structure for the state as a whole.
 The present project is a first step towards this larger objective.
 To facilitate the district administration to realize the potential of GIS in
their day-to-day affairs by providing the base layers on various
themes and capacity building for necessary update over time.
 Standardized SOI’s District boundary at 1:50 K scale in UTM & WGS
84 projection and datum as the common boundary to be in sync with
TN-SSDI as proposed in TNGIS; and later with National Spatial Data
Infrastructure (NSDI).
 The methodology for establishment of Web GIS at Cuddalore
and Nagapattinam district involves the following steps:
1) Collection and Preparation of Spatial and Attribute Datasets
for the District from the nodal departments in district and State
2) Generic Database Design and uploading Data for the District
3) Generic Web GIS Interface Development
4) Deploy the web based software along with open source GIS
software
5) Training and Handholding
Collection of Spatial and Attribute Datasets for the District
 District boundary, as provided by Survey of India at 1:50 K
scale in UTM & WGS 84 has been standardized keeping in
mind the integration of all spatial layers under State Spatial
Data Infrastructure proposed in TNGIS; and later with
National Spatial Data Infrastructure (NSDI).
 The Spatial and other Non-spatial information (digital and
conventional) were collated from varied sources in the
government domain and the discrepancies in the boundaries,
scale and the co-ordinate systems were removed for
establishing the required authentic layers for these districts.
For instance, the Revenue and Panchayat Village Boundaries
are retained as same for the villages where these boundaries
are co-terminus. Further, the required bifurcation, merging of
boundaries is carried-out for necessary revenue/panchayat
village boundaries.
Collection of Spatial and Attribute Datasets for the District
(Contd.)
 Spatial layers for Cuddalore and Nagai have been collected from
the nodal departments such as :
1. Agriculture Engineering Department
2. Tamil Nadu Water And Drainage Board
3. Institute of Remote Sensing, Anna University
4. Bharathidasan University
5. Institute of Water Studies, PWD
6. Ground Water, PWD
7. NIC / National Spatial Database
 The sources of major attribute datasets are :
1) Population Data (PCA) of Census 2001, DCO
2) Agriculture Department
3) Health Institutions Data - DPH
4) RD Panchayat Villagewise Infrastructure Data – DRD
5) Below Poverty Line Data (BPL) – DRD
6) Educational Institutions Data
7) Rainfall Data – AD, Statistics
Collection of Spatial and Attribute Datasets for the District
(Contd.)
 Necessary linking of these spatial layers with the major attribute data sets
from the respective departments is carried out, so that the regular update
of these data sets can be done without much effort. For instance, the
following major data bases are linked;
G-Return Agriculture Data
Rural Infrastructure Data
Census 2001 - Primary Census Abstract Data
Census 2001 - Village Amenities Data
7th All India Education Survey Data
PHC, HSC, Hospital Data from Public Health Department
 In addition to the above, various spatial layers like location of fire-stations,
police stations etc. are also provided with a scope to add the necessary
attribute data sets.
 Further, major efforts on building necessary spatial layers on various
natural resources like soil, water resources, delineation of watershed,
location of tanks, etc are also provided.
Generic Database Design and uploading Data
 PostgreSQL – an ORDBMS as the Backend Database and PostGIS is
an extension of PostgreSQL to support the storage of Spatial Datasets.
 The database has been designed to store the spatial or map data, the
attribute information with “Master Tables” to store the metadata –
data on spatial and attribute datasets. Master tables act as a directory.
 The design has been made in such a way that any layer would be
dynamically linked to any kind of attribute dataset. For querying and
thematic mapping this gives more scope to add / link any kind of
attribute information in future also.
 The database related activities comprise of - The corrected/reprojected
Spatial Layers (more than 80 layers) in the form of ESRI Shape File
format have been imported into PostgreSQL / PostGIS database.
 Metadata on these layers/attribute datasets have been fed into
respective master tables to enable queries in different styles / kinds of
mapping etc.
Generic WebGIS Interface Development

Web GIS has been adopted as the technology to provide interface for
the various datasets keeping in mind the large number of users

UMN MapServer is used as the Open Source Web GIS Server with
PHP/MapScript as the scripting environment. This would enable us to
host the data on any platform.

The following software modules have been currently created:
Dynamic thematic or choropleth mapping that supports following
classifications over web:
Equal Interval
Equal Count (Including zeros values).
Equal Count (Excluding zeros values)
Custom classification

Based on the metadata fed on the numeric attribute datasets, the
software decides the mapping layer which includes: Revenue villages,
Panchayat villages, Taluks and Blocks
Generic WebGIS Interface Development (Contd.)
 Simple Query module to enable query on the attribute datasets
and Complex Spatial or Administrative queries to query on GIS
and attribute datasets.
 Alphanumeric based dynamic thematic/unique symbol map
creation module to enable mapping on spatial layers like Soil,
Geomorphology, etc. based on an attribute stored in the layer itself.
 Search – Spatial Search on Administrative Units
 Authentication to check the user credentials before showing maps
 Master Entry pages to enable entry into important master tables /
metadata
 Update of attribute datasets through Excel sheets or any other
RDBMS is available for administrators
Deploy the web based software along with
open source GIS software
 The Web based software has been deployed on the Server at
Cuddalore and Nagapattinam
 Quantum GIS open source GIS software has been installed on
Clients
 Sensitization of the GIS program has been done at the district
level
 Key departments have been identified and nodal persons
nominated for taking the project forward by the respective
District Collector.
Design Architecture :
Remote User
Remote User
Remote User
Web Server (Apache / IIS)
Web Design
Style Sheets
Open Layers
JavaScript
Navigational Sequence
MapServer API/CGI
Spatial Data
PHP
Non-Spatial Data
PostgreSQL
PostgreSQL/
PostGIS
Layouts
ESRI
SHP
SQL Server
MS Access
Interaction among the Components :
PHP Scripts create
the map object and
access the database
Web Browser
PHP/Map Script
Map Server
PostGI
S
PostgreSQL Database
Generate map
images
Provides function
to
manage
geospatial data
Defin
e
PHP
class
es for
GIS
object
s
Web Server
Stor
es
Geo
spat
ial
and
busi
nes
s
dat
a
Metadata Design
Meta data
Taluk Layer
Spatial Table Name
Spatial Column to link
Non Spatial Table Name
Non Spatial Column to link
Census Table
Census Codes
…………….
………….....
Census Codes
…………….
………….....
Training and Handholding

Initial sensitization with the user departments in the districts
is done through a consultation process under the
Chairmanship of District Collector.

The necessary training programme organized at Cuddalore
and Nagapattinam in coordination with SPC and district
administration for the key personnel's in various district
departments

Necessary guidance to sustain the efforts made is being
provided for additional requirements over time.

Handholding support at the District is also extended for
some period to stabilize the system and ensure its
sustenance.
Achievements:
 The spatial queries / administrative queries will provide a good
Decision Support System for the administrators. Since the queries can
be directly made on the spatial datasets in an RDBMS environment,
the results will ensure only the up-to-date output. Any change in the
layer would reflect immediately on the result sets.
 The application provide means for importing attribute datasets even
from an Excel sheet and update the datasets periodically so that
maps would reflect the latest information. In addition, one can also
import datasets from other databases like SQL Server / MS Access
etc.
 The administrator has the complete control of the application through
which he / she may add more parameters for thematic mapping /
querying, etc by altering the metadata through the forms provided for
this purpose.
 The district environment does not restrict users with only the web
based interface. Provision of Quantum GIS – a full fledged Open
Source GIS software ensures a full functionality GIS tool for the
authenticated users in various departments to leverage the full
potential of the GIS prepared for the district.
Achievements(contd.):
Without any fresh digitization of maps and by collecting the spatial
layers from different agencies, more than 80 layers of data have been
brought under SOI’s common district boundary. Bringing these layers
within one common boundary itself had been a major task accomplished
in this project.
The deployment proposed is modeled on open source software
mentioned below. This will enable easy replication at minimum cost for
the Software tools for promoting GIS in Decentralized Planning and
development in district.
Server OS
Database
: Suse Enterprise Linux 10
: PostgreSQL / PostGIS for Attribute and
Spatial datasets
GIS Server : UMN MapServer with Open Layers for
AJAX based map rendering
Scripting
: PHP with PHP/MapScript wrapper for
MapServer
Client OS
: Suse Desktop Linux 10
GIS Software : Quantum GIS with PostgreSQL / PostGIS
Support
Achievements(contd.):
 Through State SDI initiatives (TNGIS) for the State, all the layers
prepared have been collated from different departments in digital
vector formats to avoid re-digitization activities. This could be
possible only through the SPC’s active involvement in identifying
and collecting the datasets from different the nodal departments.
 The generic database model created will enable faster replication of
the GIS application to other districts and easy integration with
attribute datasets later by the District GIS Administrator.
 Web based application interface ensures wider scope for the project
and the number of users who can access the system. The user
needs only internet connection and a browser to access the system.
 Almost all the above maps are customizable for size, colour, fill
style, titles, etc. so that the user is provided with a more flexible
map making interface.
 The application also provides a PDF output which can be used for
presentations / reports, etc.
Water bodies in Cuddalore district with Overview
window, Info Window, Legend Window
20
Spatial / Administrative Queries
TN SPC & NIC, TNSC
SKOCH SUMMIT 2009
Administrative queries
Villages with more than 6000 population but without any Health facility
22
Dynamic Buffer Map around National Highways
Administrative queries
Villages from where people have to walk
at least 1.5 km to access a health facility
24
Simple Thematic Maps - Theme on Total Population
Attribute Query and Map Output – Total Literates less
than 3000
Dynamic Unique Symbol Map Generator
GPS Schools – Source – School GIS (BDU)
Search – Chidambaram Taluk
Overlay Layers Dynamically – Apply fill styles / colours / size, etc.
Overlay layers – Taluk boundaries and Railway Lines
Layer Category wise List of Layers
List of layers prepared under this common District Boundary
Cuddalore District Layers’ Details
No
Layer Names
1
District Bounday of Cuddalore
2
Revenue Divisions of Cuddalore District
3
Taluks of Cuddalore District
4
Blocks of Cuddalore District
5
Firka of Cuddalore District
6
Assembly Constituency in Cuddalore
District
7
Parliamentary Constituency in Cuddalore
District
8
Chidambaram Parliamentary Constituency
in Cuddalore District
9
Cuddalore Parliamentary Constituency in
Cuddalore District
10
Revenue Villages of Cuddalore District
List of layers prepared under this common District Boundary
Cuddalore District Layers’
Details
No
Layer Names
11
Panchayat Villages of Cuddalore
District
12
Urban Areas of Cuddalore District
13
District Capital Location of
Cuddalore
14
Revenue Divisions Locations of
Cuddalore District
15
Taluks Capitals of Cuddalore
District
16
Blocks Capitals of Cuddalore
District
17
Firka Locations of Cuddalore
District
18
MLA's Office Locations in
Cuddalore District
19
MP's Office Locations in
Cuddalore District
20
Urban Areas Locations of
Cuddalore District
List of layers prepared under this common District Boundary
Cuddalore District Layers’ Details
No
Layer Names
21
Land Use
22
Habitations
23
District Roads
24
NH Roads
25
Railway Lines
26
Water Bodies
27
Drainage
28
Settlements
29
Forest
30
Canal
List of layers prepared under this common District Boundary
Cuddalore District Layers’ Details
No
Layer Names
31
Wells
32
Watersheds
33
Sub Watersheds
34
Mini Watersheds
35
Micro Watersheds
36
Structure
37
Wasteland
38
Wetland
39
Soil
40
Lithology
List of layers prepared under this common District Boundary
Cuddalore District Layers’ Details
No
Layer Names
41
Geomorphology
42
Agriculture
43
Wasteland
44
Rivers
45
SROs in Cuddalore
46
BSNL Exchanges Covered
47
Raingague Stations in Cuddalore
48
PHC's in Cuddalore
49
HSC's in Cuddalore
50
MLA's in Cuddalore
51
Main Locations in Cuddalore
List of layers prepared under this common District Boundary
Cuddalore District Layers’ Details
No
Layer Names
Vellar River Basin Layers
52
Vellar River Basin Boundary
53
Settlement
54
Hill
55
Hill1
56
Control_well
57
FinalControl_well
58
NewControl_well
59
Tank
60
Sub_basin_boundary_final
List of layers prepared under this common District Boundary
Cuddalore District Layers’
Details
No
Layer Names
61
Stream
62
River (Line)
63
Reservoirs
64
Rivers (Polygon)
65
Canal
66
Anaicut
67
Land Use
List of layers prepared under this common District Boundary
Cuddalore District Layers’
Details
No
Layer Names
Drainage
67
Tank
68
Sub Basin Boundary
69
Stream
70
River Line
71
Reservoir
72
River (Polygon)
73
Canal
74
Anaicut
List of layers prepared under this common District Boundary
Cuddalore District Layers’
Details
No
Layer Names
Ponnaiyar River Basin Layers
75
Ponnaiyar River Basin Boundary
76
Control Wells
77
HP&U
78
Anaicut
79
Reservoir
80
Canal
List of layers prepared under this common District Boundary
Cuddalore District Layers’ Details
No
Layer Names
81
I Order Streams
82
II Order Streams
83
III Order Streams
84
Rivers
85
Structure
86
Tanks
87
Geology
88
Geomorphology
89
Ground Water Potential
90
Land Use
91
Intersections
92
Lineaments
List of layers prepared under this common District Boundary
Cuddalore District Layers’
Details
No
Layer Names
Paravanar River Basin Layers
93
Paravanar River Basin Boundary
Other Layers
94
Police Stations
95
Accident Prone Areas
96
EB Substations