Geographical Information System (GIS): October 2014

The British National Grid (BNG)

•The British National Grid (BNG) is based on the National Grid System of England, administered by the British Ordnance Survey. The true origin of the system is at 49 degrees north latitude and 2 degrees west longitude. The false origin is 400 km west and 100 km north. Scale at the central meridian is 0.9996. The first BNG designator defines a 500 km square. The second designator defines a 100 km square. The remaining numeric characters define 10 km, 1 km, 100 m, 10 m, or 1 m eastings and northings.

• British National Grid 100 km Squares

Transverse Mercator

•Transverse Mercator projections result from projecting the sphere onto a cylinder tangent to a central meridian. Transverse Mercator maps are often used to portray areas with larger north-south than east-west extent. Distortion of scale, distance, direction and area increase away from the central meridian.

•Many national grid systems are based on the Transverse Mercator projection

Oblique Mercator

•Oblique Mercator

•Oblique Mercator projections are used to portray regions along great circles. Distances are true along a great circle defined by the tangent line formed by the sphere and the oblique cylinder, elsewhere distance, shape, and areas are distorted. Once used to map Landsat images (now replaced by the Space Oblique Mercator), this projection is used for areas that are long, thin zones at a diagonal with respect to north, such as Alaska State Plane Zone 5001.

• Oblique Mercator (Alaska State Plane Zone 5001)

The Miller projection has straight

•Miller Cylindrical

•The Miller projection has straight meridians and parallels that meet at right angles, but straight lines are not of constant azimuth. Shapes and areas are distorted. Directions are true only along the equator. The projection avoids the scale exaggerations of the Mercator map.

• Miller Cylindrical

The Mercator projection has straight

•Mercator

•The Mercator projection has straight meridians and parallels that intersect at right angles. Scale is true at the equator or at two standard parallels equidistant from the equator. The projection is often used for marine navigation because all straight lines on the map are lines of constant azimuth.

• Mercator

The Peters projection is a cylindrical

•Peters

•The Peters projection is a cylindrical equal-area projection that de-emphasizes area exaggerations in high latitudes by shifting the standard parallels to 45 or 47 degrees.

• Peters

Gall's Stereographic Cylindrical

Gall's Stereographic Cylindrical
Gall's stereographic cylindrical projection results from projecting the earth's surface from the equator onto a secant cylinder intersected by the globe at 45 degrees north and 45 degrees south. This projection moderately distorts distance, shape, direction, and area.
Gall's Sterographic Cylindrical

Behrmann Cylindrical Equal-Area

•Behrmann Cylindrical Equal-Area

•Behrmann's cylindrical equal-area projection uses 30:00 North as the parallel of no distortion.

• Behrmann Cylindrical Equal-Area

Cylindrical Projections

•Cylindrical Equal Area

•Cylindrical Equal-Area projections have straight meridians and parallels, the meridians are equally spaced, the parallels unequally spaced.

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•There are normal, transverse, and oblique cylindrical equal-area projections.

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• Scale is true along the central line (the equator for normal, the central meridian for transverse, and a selected line for oblique) and along two lines equidistant from the central line.

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• Shape and scale distortions increase near points 90 degrees from the central line.

Important

Miscellaneous projections include unprojected ones such as rectangular latitude and longitude grids and other examples of that do not fall into the cylindrical, conic, or azimuthal categories

Projection of a Sphere onto a Plane (Secant Case)

•B- Projection of a Sphere onto a Plane (Secant Case)

•In the secant case, the plane touches the sphere along a small circle if the plane does not pass through the center of the earth, when it will touch along a great circle.

Planer projection

3- Azimuthal projections result from projecting a spherical surface onto a plane.

Planer projection

A- Projection of a Sphere onto a Plane (Tangent Case(

•When the plane is tangent to the sphere contact is at a single point on the surface of the Earth.

Projection of a shere onto a cone

B- Projection of a shere onto a cone (Secant Case)

•In the secant case, the cone touches the sphere along two lines, one a great circle, the other a small circle

Conic projections

2- Conic projections result from projecting a spherical surface onto a cone.

A- Projection of a sphere onto a cone (Tangent Case)

•When the cone is tangent to the sphere contact is along a small circle.

Projection of a sphere onto a cylinder

D- Projection of a sphere onto a cylinder (Oblique case)

•When the cylinder is at some other, non-orthogonal, angle with respect to the poles, the cylinder and resulting projection is oblique.

Transverse Projection of a Sphere

C- Transverse Projection of a Sphere onto a Cylinder)tangent Case)

When the cylinder upon which the sphere is projected is at right angles to the poles, the cylinder and resulting projection are transverse

Projection of a Sphere

B- Projection of a Sphere onto a Cylinder (Secant Case)

In the secant case, the cylinder touches the sphere along two lines, both small circles (a circle formed on the surface of the Earth by a plane not passing through the center of the Earth).

Cylindrical projections

Map projections fall into four general classes.

1- Cylindrical projections result from projecting a spherical surface onto a cylinder.

A- Projection of a Sphere onto a Cylinder (Tangent Case

When the cylinder is tangent to the sphere contact is along a great circle (the circle formed on the surface of the Earth by a plane passing through the center of the Earth).

Important

•Radius of the Earth is R= 6371 km

•Periphery of the Earth = 2pR (p = 22/7)

•Distance between one degree separated latitudes is represented by 2pR/360

•Lengt•Length of i Longitude = 2pR/2

•Distance between one degree separated longitudes at Equator is represented by 2pR/360

•Distance between one degree separated longitudes at i latitude is represented by 2pR * cosqi /360

•equator to pole approx. 10,000,000 meters

• h of i Latitude = 2pR * cosqi

Top 5 Skills You Need for a Successful Career in GIS,

Conclusion Of the Study of Remote Sensing and GIS POST 7 (LAST)

Compiled By: Rauf Tabassum

Conclusion:

GIS systems have been expanding across the Country and becoming integral parts of municipal information systems. Several reasons for this are presented below:

Most municipal and county information relates back to Area ID. This information can be associated with map locations which can be efficiently and easily accessed by staff or the public using graphics-based computer programs rather than traditional paper filing systems.

A GIS allows a community to produce custom map representations upon demand. The capabilities of which are limited only by the content of the database. These capabilities are simply not feasible with manual mapping techniques.

One geo-base and set of maps are shared by all department. Updates are therefore universally available to everyone. This also translates to the ability to divide up responsibilities for system support among various departments

Geographic Information Systems (GIS) at the City may be used to:

Respond to public inquires and provide demographic information

Display and analysis of place information, such as assessed values.

Show infrastructure layouts and conditions in a clear and understandable manner

Analyze patterns such as traffic patterns and crime incidents

Perform routine operations such as application reviews and permit approvals & Provide timely information and analysis on larger policy issues requiring action

Work Flow Chart POST 6

Activities of Remote Sensing and GIS POST 5

Compiled By: Rauf Tabassum

Activities

Preparation of Project work plan for effective planning &

implementation of project.Procurement of latest high resolution

ortho satellite images (Quick bird with 0.6 m resolution/Geoeye

with 0.5m resolution) for the town planning area from NRSC

Establishment of Ground control points for georeferencing the

Satellite Images.Georefrencing the satellite images and report

generation.Digital base map creation for the project area using

rectified satellite images.Preparation of final base maps in the scale

1:5,000 & 2000 for hard copy prints.GIS digital map creation for

project area using satellite images and preparation of geodatabase

for further analysisIntegration of base map & existing land use

maps, approved layouts and administrativeboundaries for approval

and updates as per town planning department feedbacks in order to

generate a multi layered GIS map

Project Objectives POST 4

Compiled By: Rauf Tabassum

Project Objectives:

The main objective of this article explains the Preparation of

Digital base map for urban/town Planning Area by GIS

Method using High resolution Satellite images

with a resolution of 0.61m/0.51m and updations of missing

details by Total Station Survey, to generate 2D digital map

data to fit for producing hard copies of maps at basic scale of 1: 2000 & 5000 and this base map data will be

incorporated in a GIS system This Base Map will be the

base for infrastructure development for Urban/Town

planning areas in Cities.

System Requirement Study on GIS & Remote sensing requirement on project area POST 3

Compiled By: Rauf Tabassum

System Requirement Study on GIS & Remote sensing requirement on project area:

Objective of System Requirement Study (SRS) is to study, understand, analyze and put forth the broad requirements of GIS & Remote sensing technology to achieve their functional needs through GIS system development. By blending technical expertise and client requirement, the technical needs are analyzed and a System Requirement Study (SRS) document will be submitted to Town Planning department(In Future it will be called as TPD in this document) for approval and implementation.

Upon freezing Town Planning department’s requirement as detailed in this document, the further development of GIS system such as detailed design document and Prototype development shall be taken up. However for Geodatabase Design, the live data system will be shown for Town planning authorities review & approval. GIS Geodatabase creation is focused to provide the Basic layers like Road Networks, Utility lines, Infrastructure Facilities, Water bodies etc.,. Provision is kept for both vertical and horizontal expansion for the future needs of the agencies

Importance of Remote Sensing and GIS POST 2

Compiled By: Rauf Tabassum

Importance of Remote Sensing and GIS

Geographical Information system & Remote Sensing is a vital technology in any evolving national Infrastructure planning environment. Therefore, it’s a collection, interpretation, analysis, managing, storing and distribution of Geospatial data. It is very much important for urban planning activities & environmental improvement.

Efficient urban information system is a vital pre-requisite for planned development. The increasing demands in urban planning and management sectors call for co-ordinate application of Remote sensing and Geographic Information System (GIS) for sustainable development of Urban areas. There is an urgent need to adopt Remote Sensing and Geographic Information System approach in Infrastructure development. And monitoring process for implementing pragmatic plan of Urban development. The plan must incorporate an integrated approach of spatial modeling using Remote Sensing Data, GIS database and GPS solutions. This helps in evolving efficient and economical models for development and location of industries, education, housing, water supply, and service facility and disposal system.

The availability of high resolution data like WorldView-1 (0.5m), Worldview-2 (0.46m), Quickbird (0.6m) & Ikonos (1m) Resolution image satellites has revolutionized the process of masterplan map preparation & thematic mapping and spatial data base creation, specially, in the context of urban and regional planning. Whereas the technologies such as GIS has emerged as a powerful tool in integrating and analyzing the various thematic layers along with attribute information to create various planning scenarios for decision making . Remote Sensing (RS) data provides reliable, timely, accurate, and periodic data, while Geographic Information System (GIS) provide various methods of integration tools to create different planning scenarios for decision making. Therefore, the task force on urban and rural studies setup by the Planning Commission suggested the use of RS and GIS techniques for meeting the information and analysis needs of urban areas.

A Geographic Information System (GIS) may be defined as .a computer based information system which attempts to capture, store, manipulate, analyze and display spatial and tabular attribute data, for solving research, planning and management problems." A GIS is a special case of information systems where the database consists of observations in space as points, lines or areas Within a GIS distinct point, line and polygon layers are displayed together much like overhead transparencies on a projector to create maps A Geographic Information System (GIS) centrally stores information about the world in a collection of digital map layers. Rather than having information in many formats stored in multiple places like filing cabinets, different computer systems, large binders or static paper maps, a GIS pulls together very different pieces of information into one system. These map layers may be over-laid and linked together to create maps, integrate information, visualize and compare scenarios, solve problems, and more effectively manage resources.

Scientific GIS Digital Base Maps (Introduction) POST 1

Compiled By: Rauf Tabassum

Scientific GIS Digital Base Maps - Urban Planning using GIS/RS Technologies

Introduction
To achieve the objectives of making metropolis cities more livable and of international standard, a co-coordinated and integrated approach among the various agencies involved in urban development and provision of services are needed including participatory process in planning and implementation at local body levels. As well as to have planned and organized disposal of population through growth centers, which will acts as counter-magnets to the cities growth. This growth may not able to withstand the existing infrastructure, traffic, road, drainage and utility networks etc.,. Advance urban planning is required for a planned development of the area for which an accurate & up-to-date GIS digital map is a must.

Unlike other major cities such as Delhi, Mumbai etc., in our country, realization of the plan through large scale acquisition and development of land, to ensure spatial pattern of development and provision of recreational, educational and other institutional facilities, was not aimed at. Public sector lead growth and development process was not envisaged, but it was of private involved growth process (regulated by public) to achieve the objectives of town planning. The land use zoning concept adopted since 1975 was the ‘Mixed Zoning Concept’ which suit better city’s social way of life considerations, and not exclusive zoning (mostly adopted in western countries and also in zone of our metro cities) which have created major problems in our Indian cities.

To solve this problem, well planned master plans GIS maps are required for proper town planning, So this article will explaining the Concept and Preparation of Scientific GIS digital base map of major cities/for entire State by GIS/RS Method using High Resolution Satellite images with a resolution of 0.6m/0.5m and updations of missing details by Total Station Survey, to generate 2D digital map data to fit for producing hard copies of maps at basic scale of 1:5,000 & 1: 2,000 and this base map data will be incorporated in a GIS system for further town planning for Infrastructure management.

Projection Classification

Some Facts

Compiled By: Rauf Tabassum

•Length of i Longitude = 2pR/2

•Distance between one degree separated longitudes at Equator is represented by 2pR/360

•Distance between one degree separated longitudes at i latitude is represented by 2pR * cosqi /360

•equator to pole approx. 10,000,000 meters

Map Projections: the concept

Compiled By: Rauf Tabassum

•A method by which the curved 3D surface of the earth is represented on a flat 2D map surface.

•a two dimensional representation, using a plane coordinate system, of the earth’s three dimensional sphere/spheroid

•location on the 3D earth is measured by latitude and longitude;

•location on the 2D map is measured by x,y Cartesian coordinates

•unlike choice of spheroid, choice of map projection does not change a location’s lat/long coords, only its XY coords.

•Geoid and Spheroids: modeling the earth

•Latitude and Longitude: position on the model

•Datums and Surveying: measuring the model

•Map Projections: converting the model to 2 dimensions

•Scale: sizing the model

Choosing a Map Projection

Compiled By: Rauf Tabassum

•Issues to Consider:

–extent of area to map: city, state, country, world?

–location: polar, mid-latitude, equatorial?

–predominant extent of area to map: E-W, N-S, oblique?

•Rules of thumb

–Choose a standard for your organization and keep all data that way.

–Also retain lat/long coords in the GIS database if possible

–for small areas, projection is less critical and datum is more critical; reverse for large areas

–check contract; does it specify a required projection? State Plane or UTM often specified for US gov. work.

–use equal-area projections for thematic or distribution maps, and as a general choice for GIS work

–use conformal projections in presentations

–for navigational applications, need true distance or direction.

–Even though modern GIS systems are sophisticated in their handling of projections, you ignore them at your peril

Introduction To Map Projection

Compiled By: Rauf Tabassum

Introduction

Map projections are attempts to portray the surface of the earth or a portion of the earth on a flat surface. Some distortions of conformality, distance, direction, scale, and area always result from this process. Some projections minimize distortions in some of these properties at the expense of maximizing errors in others. Some projection are attempts to only moderately distort all of these properties.

Conformality

When the scale of a map at any point on the map is the same in any direction, the projection is conformal. Meridians (lines of longitude) and parallels (lines of latitude) intersect at right angles. Shape is preserved locally on conformal maps.

Distance

A map is equidistant when it portrays distances from the center of the projection to any other place on the map.

Direction

A map preserves direction when azimuths (angles from a point on a line to another point) are portrayed correctly in all directions.

Scale

Scale is the relationship between a distance portrayed on a map and the same distance on the Earth.

Area

When a map portrays areas over the entire map so that all mapped areas have the same proportional relationship to the areas on the Earth that they represent, the map is an equal-area map.

Different map projections result in different spatial relationships between regions.