GIS: TYPES OF MAP SCALES

MAPS AND MAP SCALES

Map Scale

The size of earth is too big to be represented as it is on a map. It is the relationship between distance on map and distance on ground that tells what distance on map corresponds to what distance on ground.

GIS: MAPS AND MAP SCALES

Introduction

A map is a two dimensional representation of earth surface which uses graphics to convey geographical information. It describes the geographical location of features and the relationship between them. Maps are fundamental to society.

Improvements in the fields of Geodesy, Surveying and Cartography helped in bringing the maps to their present form. The digital technology has altered the way of creating, presenting and distributing the geographic information. The conventional cartography is now getting replaced by computer aided designs and graphics, and the analog maps (paper maps) by digital maps. The growing field of technology promises to bring more advances to Cartography to render maps and allied services that serve the society in a better manner.

Source: NPTEL

CIVIL ENGINEER: Application of GIS: Tax Mapping, Business, Logistics, Emergency evacuation, Environment

Application of GIS

These include topographical mapping, socioeconomic and environment modeling, and education. The role of GIS is best illustrated with respect to some of the representative application areas that are mentioned below:

Tax Mapping:

Information about property with its geographical location and boundary is managed by GIS. Querying the GIS database can locate similar type of properties in an area. The characteristics of these properties can then be compared and valuation can be easily done .

Business: 

A GIS with relevant data such as number of consumers, brands and sites they go for shopping can give any business unit a fair idea whether their unit if set up is going to work at a particular location the way they want it to run.

Logistics:

It is necessary for the shipping companies to know where their warehouses should be located, which routes should the transport follow that ensures minimum time and expenditures to deliver the parcels to their destinations. All such logistics decisions need GIS support.

Emergency evacuation: 

It is important to know in which area the risk is higher, the number of individuals inhabiting that place, the routes by which the vehicles would move to help in evacuating the individuals. Thus preparing an evacuation plan needs GIS implementation.

Environment: 

GIS is being increasingly involved in mapping the habitat loss, urban sprawl, land-use change etc. Mapping such phenomena need historical landuse data, anthropogenic effects which greatly affect these phenomena are also brought into GIS domain. GIS models are then run to make predictions for the future.

References

Burrough, P. A & McDonnell, R. A. 1998, Principles of geographical information systems, Oxford University Press, UK.

CIVIL ENGINEER: Introduction TO GIS, Objectives of GIS, Components of GIS

1. INTRODUCTION TO GIS

GIS stands for Geographical Information System. It is defined as an integrated tool, capable of mapping, analyzing, manipulating and storing geographical data in order to provide solutions to real world problems and help in planning for the future. 

Objectives of GIS

Some of the major objectives of GIS are to:

-Maximizing the efficiency of planning and decision making

-Integrating information from multiple sources

-Facilitating complex querying and analysis

-Eliminating redundant data and minimizing duplication

-Components of a GIS

A GIS has following components:

Hardware : It consists of the equipment's and support devices that are required to capture, store process and visualize the geographic information. These include computer with hard disk, digitizers, scanners, printers and plotters etc.

Software : The GIS software must have the basic capabilities of data input, storage, transformation, analysis and providing desired outputs. The interfaces could be different for different software's. ArcGIS by ESRI is the widely used proprietary GIS software. Others in the same category are MapInfo, Microstation, Geomedia etc. The development of open source GIS has provided us with freely available desktop GIS such as Quantum, uDIG, GRASS, MapWindow GIS etc., GIS softwares.

Data : The data is captured or collected from various sources (such as maps, field observations, photography, satellite imagery etc) and is processed for analysis and presentation.

Procedures : These include the methods or ways by which data has to be input in the system, retrieved, processed, transformed and presented.

People : This component of GIS includes all those individuals (such as programmer, database manager, GIS researcher etc.) who are making the GIS work, and also the individuals who are at the user end using the GIS services, applications and tools.

(Source IIT DELHI)