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MAPS, CARTOGRAPHY

& SIGNIFICANCES

by

Prof . A. BALASUBRAMANIAN

Centre for Advanced Studies in Earth Science,

University of Mysore, Mysore

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What is a map?

A Map is a drawn, pictorial representation of the earth

or its features.

Most maps show part or all of the earth's surface

features.

Maps express information through lines, coloured

zones, shapes, and other symbols.

These symbols stand for such features as rivers, roads,

and cities.

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To analyse the earth’s surface features, we need some

accurate information about their distribution. These

information are available only on maps.

Maps are used to locate places, measure distances,

plan trips, and find our way.

People probably made crude maps even before the

development of written language sometimes

before 5,500 years.

Through expeditions and explorations more and

more information were added to the old maps.

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Map is a drawn or printed representation of the

physical features of the Earth.

It is the best tool to show, understand and analyse

the features of an area.

Cartography is the art and science of making maps.

Pilots of ships and aeroplanes use maps to navigate.

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Maps may also give us information about the

variation of a property, such as the climate,

population, and transportation routes.

Scientific discoveries have made maps more accurate.

Today, most maps are based on photographs taken

from the air.

Maps express information through lines, colours,

shapes, and other symbols.

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These symbols stand for such features as rivers, roads,

and cities.

It is not possible to show features at their actual size

nor is it possible to show full detail.

The features represented on a map are greatly reduced

in size. Every map has its own scale. Scale is the

ratio between the distance of a part of a map and its

ground distance.

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For example, one centimetre on a map might

represent a distance of 500 metres.

Different scale maps provide different levels of detail

in terms of features presented.

Different types of maps are prepared for different

purposes.

For geological exploration, geologists use the

topographic maps.

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The spatial information displayed in a topographic

map are more when compared to the general maps.

Understanding the features of these topographic maps

require some basic skills. Today let us see the

features of a topographic map.

Topographic maps:

Topographic maps usually portray both natural and

man-made features.

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The natural features include mountains, valleys,

plains, lakes, rivers, and forests.

The man-made features include roads, boundaries,

transmission lines, and major buildings.

Maps express these information in the form of lines,

colours, shapes, and other symbols.

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The wide range of information provided by a

topographic map makes it extremely useful to

professional geologists.

These maps are made in two standard scales. The first

one is of 1: 250000 scale. In this large scale map, a

feature of 1 cm is equal to 2,50,000 cm.

The second one is 1: 50000 scale.

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These are small scale maps. One cm over this map is

equal to a distance of 500 metres.

One topographic map of 1: 250000 scale includes 16

sets of 1: 50000 scale maps.

Let us see the features of a Topographic Map:

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Topographic maps show four categories of features

as:

1. Geographic features

2. Topographic features

3. Hydrographic features

4. Cultural features.

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Geographic features:

This category includes the spatial distribution of

earth’s features with reference to their geographic co-

ordinates, its index, the boundaries covered with

reference to both latitudes and longitudes, scale and

links to other maps and their features.

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Topographic maps render the three-dimensional ups

and downs of the terrain on a two-dimensional

surface.

The characteristic that distinguishes topographic maps

from other maps is the use of contour lines to portray

the shape and elevation of the land.

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Topographic maps are used for engineering, energy

exploration, natural resource conservation,

environmental management, public works design,

commercial and residential planning, and outdoor

activities like hiking, camping, and fishing.

Map Symbols

All features are represented on a topographic maps

by a set of standard symbols.

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For example, the topography (the shape of the land) is

shown by contour lines. Usually brown, these lines

show the ground surface at a constant elevation.

Woodlands are shown in a green tint;

waterways, in blue.

Buildings may be shown on the map as black squares

or outlines. Recent changes in an area may be shown

by a purple overprint.

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A road may be printed in red or black solid or dashed

lines, depending on its size and surface.

Reading a map:

Using a map requires certain skills.

To read a map, it is necessary to understand map

legends, scale, geographic grids, and map indexes.

Map legends list and explain the symbols and colours

on a map.

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Some map symbols resemble or suggest the features

they represent. For example, a tree-shaped symbol

may stand for a forest or an orchard. But many

symbols have no resemblance to what they represent,

as when a circle stands for a city. In addition, the

same symbol may represent different features on

different maps. A circle, for instance, may represent

20 mobile homes on one map and a petroleum deposit

on another. It is important to read the map legend to

find out exactly what the symbols mean.

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Most maps are printed to show north at the top. Many

map legends include an arrow that indicates which

direction is north.

Uses of Maps:

People probably made crude maps even before the

development of written language some 5,500 years

ago.

Through the years, people have explored more of the

world, adding new information to maps. Scientific

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discoveries have made maps more accurate.

Today, most maps are based on photographs taken

from the air.

We use maps to locate places, measure distances, plan

trips, and find our way.

Pilots of ships and aeroplanes use maps to navigate.

Maps may also give us information about a place,

such as its climate, population, and transportation

routes.

Maps can also show such patterns as where people

live and how they use the land.

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We also use maps to make comparisons and draw

conclusions.

Geologists study maps of the earth's structure to help

locate natural resources.

Map legends list and explain the symbols and colours

on a map.

Some map symbols resemble or suggest the features

they represent.

For example, a tree-shaped symbol may stand for a

forest or an orchard.

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But many symbols have no resemblance to what they

represent, as when a circle stands for a city.

In addition, the same symbol may represent different

features on different maps.

It is important to read the map legend to find out

exactly what the symbols mean.

Scale - Every map may have a scale.

The features represented on a map are greatly reduced

in size, as per its scale.

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For example, on a 1:50,000 scale map, one centimetre

on a map might represent a distance of 500 metres.

A map's scale shows the relationship between

distances on the map and the corresponding distances

on the earth's surface.

Many maps show scale by marking off distances on a

straight line.

Each mark represents a certain number of kilometres

or miles.

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Other maps indicate scale in words and figures.

For example, the scale might appear as "1

centimetre:10 kilometres."

In other words, a distance of 1 centimetre on the map

represents 10 kilometres on the earth's surface.

Another common method of expressing scale is by a

representative fraction, such as "1:100,000" or

"1/100,000."

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This means that a single unit of length on the map

represents 100,000 of those units on the earth's

surface.

Reading a map:

Map Legend. Using a map requires certain skills. To

read a map, it is necessary to understand map legends,

scale, geographic grids, and map indexes.

Longitude and latitude can be used to pinpoint any

place on earth.

For example, only one place can lie at 30° north

latitude and 90° west longitude.

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Map indexes help us locate places on a map.

A map index lists the features shown on a map in an

alphabetical order.

In many atlases, each entry in the index is listed with

its longitude and latitude.

We can then use the longitude and latitude to find a

feature on a map.

Many maps are divided into horizontal rows and

vertical columns by an index grid.

In most cases, letters along the sides of the map label

the horizontal rows.

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Numbers across the top and bottom of the map label

the vertical columns.

General reference maps identify and locate a variety

of geographic features.

Such maps may include land features, bodies of water,

political boundaries, cities and towns, roads, and

many other elements.

People use general reference maps to locate specific

places and to observe their location in relation to other

places.

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The maps of states, countries, and continents in

atlases are examples of general reference maps.

Maps that emphasize the boundaries of counties,

states, countries, or other political units are called

political maps.

Maps that emphasize the location of such features of

the earth's surface as mountains, rivers, and lakes are

called physical maps or terrain maps.

Mobility maps are designed to help people find their

way from one place to another.

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There are mobility maps for travel on land, on water,

or in the air.

A map used to navigate a ship or an aeroplane is

called a chart.

Road maps are the most familiar kind of mobility

map.

Road maps represent different categories of roads,

such as motorways, four-lane roads, and scenic routes.

They also show the cities, towns, parks, and other

places connected by those roads.

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Travellers use road maps to plan trips and follow

lengthy routes.

Street maps are similar to road maps. But street

maps show a much smaller area in much greater

detail. People use street maps to find specific

addresses and to plan and follow short routes.

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Transit maps show the routes of buses, underground

railways, and other systems of mass transit (public

transport in cities).

Such maps help people reach their destinations by

means of public transport.

Aeronautical charts are maps used to navigate

aeroplanes.

Many pilots of small, low-flying aircraft plan and

follow a course by using VFR (visual flight rules)

charts.

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VFR charts show such landmarks as bridges, roads,

railway tracks, rivers, and towns.

Nautical charts are maps used to navigate ships and

boats.

Nautical charts show water depths, lighthouses,

buoys, islands, and such dangers as coral reefs and

underwater mountains that come near the surface.

They also locate the source of radio signals that

navigators use to determine their course and position.

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Thematic maps:

Show the distribution of a particular feature such as

population, rainfall, or a natural resource.

They are used to study overall patterns.

A thematic map might show, for example, where

petroleum is produced in Asia or how the average

yearly rainfall varies from one part of one place to

another.

Some thematic maps express quantities by using lines

that pass through points of equal value.

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General terms for such lines include isograms,

isolines, and isarithms.

Specific types of isograms have special names.

On a weather map, for example, lines called isobars

connect places that have the same air pressure (eg.

Isobar).

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Isograms may also indicate temperatures,

precipitation, and other measurements.

On topographic maps, which show surface features of

the land, isograms called contour lines are used to

depict areas of equal elevation.

Some thematic maps use variations in size and shape

to express quantities. A map of the international

petroleum trade might indicate a large flow of oil with

thick arrows and a small flow of oil with thin arrows.

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Inventory maps, like thematic maps, concentrate on a

specific feature.

But unlike thematic maps, which show distributional

patterns, inventory maps show the precise location of

the specific feature.

A map showing every building in a community is an

example.

Map projections:

Any system for transferring parallels and meridians

from a globe onto a flat map is called a projection.

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Mapmakers create projections according to

mathematical formulas, often with the aid of

computers.

It is impossible to project a sphere, such as the earth's

surface, onto a flat surface with complete accuracy.

Every flat map has inaccuracies in scale that result

from shrinking the globe in some places and

stretching it in others to flatten it.

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Some maps distort (show inaccurately) distances.

On such maps, equal land areas may not appear of

equal size.

Many maps distort angles, resulting in misshapen seas

and continents.

Nearly all maps have one or two points or lines where

there is no distortion.

These are called standard points or standard lines.

As we move away from them, the distortion of scale

increases in a predictable way.

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How maps are made?

Experts from many fields gather the information that

cartographers need.

The cartographer then transforms this information

into a meaningful visual representation.

In general, mapmaking follows these steps:

(1) observation and measurement,

(2) planning and design,

(3) drawing and reproduction, and

(4) revision.

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Cartography is the art of making and study of maps.

Someone who makes or studies maps is a

cartographer.

Types of maps:There are many kinds of maps.

The most familiar types are

(1) general reference maps,

(2) mobility maps,

(3) thematic maps, and

(4) inventory maps.

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Observation and measurement:

A variety of experts obtain the information shown on

maps. The geodesist provides precise measurements

of the earth's size and shape.

The surveyor works out the location and boundaries

of places by measuring distances, angles, and

elevations.

The photogrammetrist obtains measurements from

aerial photographs.

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Some of the other specialists who contribute

information include census takers, geographers,

geologists, and meteorologists.

The production of new maps based on aerial

photographs and other original surveys is called base

mapping.

Most maps made by base mapping are topographic

maps that are large in scale and include much detail.

They become the basis for many other maps made by

the process of compilation mapping.

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HISTORY OF MAPS-

Ancient maps.

The oldest existing map appears on a clay tablet made

in Babylonia (now part of Iraq) around 2500 B.C.

This map seems to show a settlement in a mountain-

lined river valley.

The Egyptians made maps as early as 1300 B.C. They

developed techniques of surveying, probably to remap

property boundaries each year after the Nile River

flooded its banks.

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The Greeks made great advances in geometry and

surveying, and they developed systems of map

projection.

The Greeks also speculated about the size and shape

of the earth.

Many of them believed it was a sphere.

The Greek mathematician Eratosthenes calculated the

circumference of the earth with remarkable accuracy

around 250 B.C. The development of thematic

mapping. By the 1800's, the systematic collection of

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data through censuses had become common.

Cartographers then created thematic maps to display

and study this wealth of new information.

Mapmaking and modern technology:

During the 1900's, improvements in printing and

photography have made it cheaper and easier to

produce maps.

Maps became more widespread as a result.

The development of the aeroplane during the early

1900's helped to prepare maps faster.

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Space exploration has also contributed to mapmaking

and has furthered the mapping of moons, other

planets, and the vast reaches of space.

Artificial satellites carry remote sensing devices that

send a variety of signals back to earth. These signals

can be used in mapping landforms, mineral deposits,

patterns of vegetation growth, environmental

pollution, and other subjects.

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Some of the Major Types of Maps:

Physiographic map,

Topographic map,

Drainage maps .

Geological map,

Structural map,

Infrastructural maps.

Geophysical maps,

Hydrogeological maps.

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Mining maps,

Hazard zonation maps.

Environmental -

Landscape,

Vegetation,

Precipitation,

Climatic, etc.

Geographic Maps -

Political, Country, State, Local, City, Highway, Road .

Statistical - Population,

Economic activity,

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Linguistic maps,

Urban settlement maps,

Aviation maps,

Navigational maps,

Cadastral maps,

Resource maps- land, soil, water, vegetation, wildlife,

mineral, fuel, energy, etc.

KINDS OF MAPS PREPARED :

Geology ,Forest Fires, Land , Hydrology , Natural

Hazards, Ecology, Age of Rocks, Geological

Provinces, Major Rock Categories, Fire Danger

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Rating, Forest Fire Hotspots, Land Cover, Permafrost,

Relief, Surficial Materials, Surficial Materials, World

Heritage Sites, Current Water Levels, Drainage

Basins, Major Avalanches ,Major Earthquakes, Major

Floods, Major Forest Fires, Major Hailstorms, Major

Hurricanes ,Major Landslides, major Tornadoes,

Major Volcanic Areas, Tsunamis, Ecological

Framework , Ecosystem Components, Human

Activities in Ecosystems, Protecting Ecosystems,

Threats to Ecosystem Ecological Framework,

Terrestrial Ecozones, Endemic Plant Diversity, Land

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Cover Diversity ,Rare Plant Diversity, Wetland

Diversity, Mining Sites, Productive Forest Land Use

.Protected Areas ,Industrial Discharge Sites.

Population Variation by Eco-Province, Road Density

,Sewage Treatment, Species at Risk, Aboriginal

Languages, Aboriginal Population, Population, Age ,

Families ,,Official Languages, Aboriginal Languages

by Community, Index of Aboriginal Language Ability,

Percentage of Population by Census Division,

Population Density, Population Distribution, Youth

,Family Structure, Marital Status,

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Families With Children Living at Home

Mining, Special Places ,Transportation Infrastructure,

Active and Closed Mines,

Mineral Exploration , Drainage Basins, geological

Provinces, Permafrost . Snowfall ,Aboriginal Cultural

Areas,

Heritage Rivers, Migratory Bird Sanctuaries,

National Historic Sites ,

National Parks, National Wildlife Areas ,Air Routes.

Marine Transportation, Bilingualism, Knowledge of

English, Mother Tongue,

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Agriculture, Income, Diamond Exploration,

Renewable Energy,

Resource Reliant Communities,

Electric Power Generating Stations, Beef Cattle by

Census, Dairy Cattle by Census .

Small Farms by Census,

Wheat Acreage by Census. Median Income of

Individuals, Male Median Income. Female Median

Income.

Areas for MINERAL Exploration, Surficial Materials.

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Renewable Energy,

Combined Energy,

Forestry , Minerals,

All Resources, Energy, Forestry, Utility Stations,

Mining and Energy Industries,

Territorial Evolution, International Outline Maps,

Political Divisions, Coastline Boundaries, Coastline,

Adjacent Regions, lakes, Rivers, Capital City

Locations,

Place Locations & Names,

Climate Warming, Potential Impacts,

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Stress to the Atmosphere, Human Activities Leading

to Emissions , societal Responses ,annual

Temperature,

Coastal Sensitivity to Sea-level Rise,

Sensitivity of Peatlands to Climate Change, Severity

Ratings for Forest. Wind Erosion Risk and Climate

Sensitivity, Greenhouse Gas Emissions by Gas

,Greenhouse Gas Emissions by Sector ,Trends in

Greenhouse Gas Emissions ,Light-duty Vehicle Fuel

Efficiency. Market Share,

Change in Market Share. Distribution of Freshwater ,

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Water Consumption. Recreational Uses,

Drainage Patterns, Glaciers and Icefields,

Groundwater, Wetlands,

Domestic Water Consumption,

Commercial and Institutional Water Consumption,

Agricultural Water, Consumption / Irrigation,

Hydroelectricy and Freshwater, Swimming ZONES,

Recreational Fishing,

Boating TYPES.

Health Resources,

Health Status ,

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Non-medical Determinants of Health, Health

Behaviors ,

Health Services Utilization, Population-to-physician

Ratios.

Population-to-family Physician Ratios, Population-to-

nurse Ratios, Low Birthweight,

Physically Active Population, Population Who Were

Overweight.

Dental Services Utilization,

Where to Purchase, Natural Resources,

Find a Place.

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Natural Resources Mapping:

Earth’s environmental segments contain innumerable

natural resources for human use and consumption.

Maps depict most of them for human use and

analysis.