TABLE OF CONTENTS · Figure 2: Contour lines. 7 Figure 3: Layer Tinting 8 Figure 4: Spot Height 8...
Transcript of TABLE OF CONTENTS · Figure 2: Contour lines. 7 Figure 3: Layer Tinting 8 Figure 4: Spot Height 8...
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TABLE OF CONTENTS
1. INTRODUCTION: ..................................................................................................................... 4
2. CONCEPT AND CATEGORIZATION OF MAP: .................................................................... 4
3. BASIC ELEMENTS OF TOPOGRAPHIC MAPS: ................................................................... 5
4. METHODS OF SHOWING RELIEF ......................................................................................... 7
5. DEFINITION OF IMPORTANT TOPOGRAPHIC TERMS: ................................................... 8
6. HOW TO DETERMINE A SLOPE: ........................................................................................ 10
7. INTERPRETATION OF TOPOGRAPHIC MAP: ................................................................... 11
7.1: PROVIDED MAP.............................................................................................................. 11
7.2: PHYSICAL ANALYSIS OF THE SUPPLIED MAP ....................................................... 11
7.3: CULTURAL INFORMATION OF THE SUPPLIED MAP ............................................. 12
7.4: ANALYSIS BETWEEN THE PHYSICAL AND CULTURAL RELATIONS OF THE
SUPPLIED MAP ...................................................................................................................... 13
7.5: PREDICTION AFTER 24 YEARS ................................................................................... 14
8. GEOLOGIC MAP AND ITS TYPES....................................................................................... 17
9. IMPORTANCE OF GEOLOGIC MAP: .................................................................................. 18
10. USES OF GEOLOGIC MAPS: .............................................................................................. 19
11. STAGES TO FORM A GEOLOGIC MAP: ........................................................................... 21
12. DEFINITION OF IMPORTANT GEOLOGIC TERMS:....................................................... 24
13. WEATHER MAP ................................................................................................................... 28
14. SIGN AND SYMBOL OF A WEATHER MAP:................................................................... 29
15. DIFFERENCE BETWEEN WEATHER AND CLIMATE: .................................................. 39
16. CONCLUSION: ...................................................................................................................... 40
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LIST OF FIGURES
LIST OF TABLES
Table Page
Table-1: Difference between Weather and Climate 40
LIST OF MAPS
Map Page
Map 1: Geologic map of Bangladesh 20
Map 2: Current Weather map of Bangladesh 28
Attached map from provided sample 12
Figure Page
Figure 1: Basic Elements of a Topographic Map 6
Figure 2: Contour lines. 7
Figure 3: Layer Tinting 8
Figure 4: Spot Height 8
Figure 5: Bench Mark 9
Figure 6: Trigonometrical Station 9
Figure 7: Major fault lines of the world 9
Figure 8: Lithology of Outcrop and Field Structure Sketch. 22
Figure 9: Strike/Dip Data Plot and Indication of Geology Structure. 22
Figure 10: Data Plot on 25° 23
Figure 11: How to Make Cross Section 24
Figure 12: Hutton Unconformity 25
Figure 13: A Faulting in Morocco 26
Figure 14: Strike 26
Figure 15: Time symbol 29
Figure 16: High and Low Pressure Centre 30
Figure 17: Isobar 31
Figure 18: Weather Fronts and Features 32
Figure 19: Weather Station Plot 33
Figure 20: Weather Map Symbols for Current Weather 34
Figure 21: Sky Cover Symbols 35
Figure 22: Weather Map Symbols for Clouds 36
Figure 23: Wind Direction and Wind Speed Symbols 37
Figure 24: Precipitation Areas and Symbols 38
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SECTION-1:
TOPOGRAPHIC MAP
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1. INTRODUCTION: Map study is the essential part for studying geography and gaining advance and basic knowledge
of cartography as well. There are several sorts of map such as topographic map, thematic map,
geologic map, weather map etc. Details of the study of maps are discussed throughout this
notebook. Also the provided sample in the cartographic lab has been analyzed and attached with
the notebook.
2. CONCEPT AND CATEGORIZATION OF MAP: A map is a symbolic depiction emphasizing relationships between elements of some space, such
as objects, regions, or themes. Geographic map is the study and practice of crafting
representations of the Earth upon a flat surface.
Road maps are perhaps the most widely used maps today, and form a subset of navigational
maps, which also include aeronautical and nautical charts, railroad network maps, and hiking and
bicycling maps. In terms of quantity, the largest number of drawn map sheets is probably made
up by local surveys, carried out by municipalities, utilities, tax assessors, emergency services
providers, and other local agencies.
There are several types of maps. Such as-
i. POLITICAL MAPS: A political map does not show topographic features like
mountains. It focuses solely on the state and national boundaries of a place. They also
include the locations of cities large and small, depending on the detail of the map.
ii. PHYSICAL MAPS: A physical map is one documents landscape features of a place.
They generally show things like mountains, rivers, and lakes. Bodies of water are always
shown with blue. Mountains and elevation changes are usually shown with different
colors and shades to show relief. Normally on physical maps, green shows lower
elevations while browns show high elevations.
iii. TOPOGRAPHIC MAPS: A topographic map is similar to a physical map in that it
shows different physical landscape features. Unlike physical maps, this type of may uses
contour lines instead of colors to show changes in the landscape. Contour lines on
topographic maps are normally spaced at regular intervals to show elevation changes (e.g.
each line represents a 100-foot (30 m) elevation change) and when lines are close
together the terrain is steep.
iv. CLIMATE MAPS: A climate map shows information about the climate of an area. They
can show things like the specific climatic zones of an area based on the temperature, the
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amount of snow an area receives or the average number of cloudy days. These maps
normally use colors to show different climatic areas.
v. ECONOMIC OR RESOURCE MAPS: An economic or resource map shows the
specific types of economic activity or natural resources present in an area through the use
of different symbols or colors depending on what is being shown on the map.
vi. ROAD MAPS: A road map is one of the most widely used map types. These maps show
major and minor highways and roads (depending on detail), as well as things like
airports, city locations and points of interest such as parks, campgrounds, and
monuments. Major highways on a road map are generally shown in red and larger than
other roads, while minor roads are a lighter color and a narrower line.
vii. THEMATIC MAPS: A thematic map is a map that focuses on a particular theme or
special topic. They are different from the six aforementioned general reference maps
because they do not just show natural features like rivers, cities, political subdivisions,
elevation, and highways. If these items are on a thematic map, they are background
information and are used as reference points to enhance the map's theme.
3. BASIC ELEMENTS OF TOPOGRAPHIC MAPS: The basic elements of a topographic map are discussed below.
1. Title: A topographic map must have a title expressing the primary purpose of drawing
the map at the top corner of the map.
2. Coordinate system: Topographic map must have coordinate system showing the latitude
and longitude. A topographic map May have more than one grid system. Latitude is at the
top and bottom of the map and longitude is found at the both sides of the map.
3. Contour lines: A contour line is the imaginary horizontal line that connects all points in
a field which have the same elevation. A contour line is imaginary but can be visualized
by taking the example of a lake. The water level of a lake may move up and down, but
the water surface always remains horizontal. The level of the water on the shore line of
the lake makes a contour line because it reaches points which are all at the same
elevation.
4. Indicating Color: A topographic map should have some indicating colors such as-blue
for water, green for forest, brown for contour lines, black for cultural features etc.
5. Direction: Like other maps, topographic map should show the direction points such as
northwards or magnetic declination from northwards.
6. Slopes: A slope is the rise or fall of the land surface. It is important for the farmer or
irrigator to identify the slopes on the land.
7. Elevation of a point: Any sort of elevation of a point should be shown in the topographic
map.
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8. Depression of a point: The depression of any point should be shown in the topographic
map in the same way of showing an elevation point.
9. Other elements: The topographic map has other elements of a map such as scale, legend,
boundary, RF etc.
The following legend is a sample showing the various elements of a topographic map.
Figure 1: Basic Elements of a Topographic Map
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4. METHODS OF SHOWING RELIEF Mapmakers use several methods to depict relief of the terrain.
a. Layer Tinting. Layer tinting is a method of showing relief by color. A different color is used
for each band of elevation. Each shade of color, or band, represents a definite elevation range. A
legend is printed on the map margin to indicate the elevation range represented by each color.
However, this method does not allow the map user to determine the exact elevation of a specific
point—only the range.
b. Form Lines. Form lines are not measured from any datum plane. Form lines have no
standard elevation and give only a general idea of relief. Form lines are represented on a map as
dashed lines and are never labeled with representative elevations.
c. Shaded Relief. Relief shading indicates relief by a shadow effect achieved by tone and
colors that result in the darkening of one side of terrain features, such as hills and ridges. The
darker the shading, the steeper the slope. Shaded relief is sometimes used in conjunction with
contour lines to emphasize these features.
d. Hachures. Hachures are short, broken lines used to show relief. Hachures are sometimes
used with contour lines. They do not represent exact elevations, but are mainly used to show
large, rocky outcrop areas. Hachures are used extensively on small-scale maps to show mountain
ranges, plateaus, and mountain peaks.
e. Contour Lines. Contour lines are the most common method of showing relief and elevation
on a standard topographic map. A contour line represents an imaginary line on the ground, above
or below sea level. All points on the contour line are at the same elevation. The elevation
represented by contour lines is the vertical distance above or below sea level. The three types of
contour lines used on a standard topographic map are as follows:
Figure 2: Contour lines.
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(1) Index. Starting at zero elevation or mean sea level, every fifth contour line is a heavier line.
These are known as index contour lines. Normally, each index contour line is numbered at some
point. This number is the elevation of that line.
(2) Intermediate. The contour lines falling between the indexes contour lines are called
intermediate contour lines. These lines are finer and do not have their elevations given. There are
normally four intermediate contour lines between index contour lines.
(3) Supplementary. These contour lines resemble dashes. They show changes in elevation of at
least one-half the contour interval. These lines are normally found where there is very little
change in elevation, such as on fairly level terrain.
5. DEFINITION OF IMPORTANT TOPOGRAPHIC TERMS: There are some important terms that need to be defined before incepting a in-depth discussion
about the map study. Those are defined below.
Layer Tinting: A method of showing relief on
maps and charts by coloring different levels in
different shades. The basic shades are those of
brown. The darker the shade, the higher is the
height above sea level. The altitudes represented
by each tint are indicated on the maps and charts.
Sometimes referred to as elevation tint or layer
tint. Also called altitude tinting.
Spot Height: A spot height is an exact point on a
map with an elevation recorded beside it that
represents its height above a given datum.It‟s the
eleveation of certain point. Simply, it‟s a mark on
a map indicating the height of a hill, mountain,
etc.
Figure 3: Layer Tinting
Figure 4: Spot Height
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Bench Mark: A benchmark is a point of
reference by which something can be measured.
In surveying, a "bench mark" (two words) is a
post or other permanent mark established at a
known elevation that is used as the basis for
measuring the elevation of other topographical
points.
Trigonometrical Station: A triangulation
station, also known as a triangulation pillar,
trigonometrical station, trigonometrical point,
trig station, trig beacon, or trig point, and
sometimes informally as a trig, is a fixed
surveying station, used in geodetic surveying and
other surveying projects in its vicinity.
Fault Lines: Fault lines are some straight
lines shown in the map to indicate the fault
surface. It‟s often associated with the
topological and geological fetaures of a land
formt. It is a break or fracture in the ground
that occurs when the Earth's tectonic plates
move or shift and are areas where
earthquakes are likely to occur.
Gradient Analysis: Gradient analysis refers to the measurement and interpretation of the
gradients of a topographic map, including the methods to determine the gradients.
Gradient is a term to define the steepness of a slope regarding either the inclination or
declination.
Figure 5: Bench Mark
Figure 6: Trigonometrical Station
Figure 7: Major fault lines of the world
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Frontline: Front refers to the border zone between two contrasting air masses and
usually in temperature. Front lines are used to indicate the border zone in a
topographic map.
6. HOW TO DETERMINE A SLOPE: A To calculate the slope of a line you need only two points from that line, (x1, y1) and (x2, y2).
The equation used to calculate the slope from
two points is:
On a graph, this can be represented as:
𝑆𝑙𝑜𝑝𝑒 =(y2− y1)
(𝑥2− 𝑥1)
There are three steps in calculating the slope of a straight line when you are not given its
equation.
1. Step One: Identify two points on the line.
2. Step Two: Select one to be (x1, y1) and the other to be (x2, y2).
3. Step Three: Use the slope equation to calculate slope.
A moment should be taken to work through an example where we are given two points.
Example
Let's say that points (15, 8) and (10, 7) are on a straight line. What is the slope of this line?
1. Step One: Identify two points on the line.
In this example we are given two points, (15, 8) and (10, 7), on a straight line.
2. Step Two: Select one to be (x1, y1) and the other to be (x2, y2).
It doesn't matter which we choose, so let's take (15, 8) to be (x2, y2). Let's take the point (10, 7)
to be the point (x1, y1).
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3. Step Three: Use the equation to calculate slope.
Once we've completed step 2, we are ready to calculate the slope using the equation for a slope:
We said that it really doesn't matter which point we choose as (x1, y1) and which to be (x2, y2).
Let's show that this is true. Take the same two points (15, 8) and (10, 7), but this time we will
calculate the slope using (15, 8) as (x1, y1) and (10, 7) as the point (x2, y2). Then substitute these
into the equation for slope:
The same is found answer as before.
7. INTERPRETATION OF TOPOGRAPHIC MAP:
7.1: PROVIDED MAP The provided map is named as “BANGLADESH-INDIA; DINAJPUR, JAIPURHAT AND
RANGPUR DISTRICT, WEST BENGAL”. Supplied sample number 78 G/3. It shows the
Physical and Cultural futures of Dinajpur, Jaipurhat and Rangpur districts. It shows both the area
of Bangladesh and India.
7.2: PHYSICAL ANALYSIS OF THE SUPPLIED MAP The physical features are mentioned and analyzed below-
Terrain: The terrain of the supplied map is mostly flat. It contains agricultural
area, transport and cultural phenomena.
Elevation: The elevation points are very few. The area is almost a flat area with
forests and transportation. Much elevation points are not observed.
Depression: The depression points are not as few as elevation points but there
are not greater in number as well. There are few lakes, rivers and water bodies
that can be considered as depression area or points.
Mountains Valleys: The amount of mountain is closer to zero. No notable
mountains are observed in the map. Consequently, the amount of valleys is few
as well.
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Vegetation Coverage: There is a great area with vegetation coverage. There are
trees, forests, cultivation lands, trees, confines, shrubs, herbs, grass, cane,
bamboo in the map. The vegetation coverage is observed in every transportation
area and settlement area as well.
Hydrology: There are notable number of water bodies, marshes, ponds, rivers,
lakes etc. A branch of Teesta River has been flowing near Chota Padampur. It
has some canals and probable floodplains.
Valley and Floodplains: The river valley creates some notable floodplains in
the mapped area and valleys are not in greater numbers.
7.3: CULTURAL INFORMATION OF THE SUPPLIED MAP The cultural features are mentioned and analyzed below-
1. Settlement Pattern: The settlement patterns in the mapped area are of four
types-nuclear settlement, semi-nuclear settlement, scattered settlement and linear
settlement.
Nuclear settlement: Found in the area of the absence of
transportation or river or canals.
Semi-nuclear settlement: Found between the nuclear and linear
pattern of settlement.
Linear settlement: Found near railroads, roads, rivers and
canals.
Scattered settlement: The scattered settlement in the studied map
is without any pattern. The can be found dispersedly anywhere in
the map; probably because of the domination of the forest areas.
2. Transportation Network: In the studied map, there are 3 types of the
transportation. These are- railroads, roads and water transport.
Railroads: Railroads are found throughout the entire area of the
maps. Both national and international railroads are observed.
Railroads crossed international border area between Bangladesh
and India at the south western part of the map. Broad gauge, small
gauge, double gauge etc. are observed in different parts of the
area.
Roads: Roads are observed at the linkage of railroads. Many
areas where railroads don’t go, roads are the available transport
there, according to the map.
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Water Transport: Water transports are not greater in amount.
Some water routes are observed at the north western part of the
map along with the Teesta River.
3. Occupation: Occupation of the people can be assumed considering the natural
resources, cultural features and physical features of the map. Mainly they are
dependent on primary economic activities for livelihood. Their possible
occupations are given below.
Farming: Vast agricultural areas are available; consequently people are
dependent on agricultural activities such as farming, cultivating, crop
production, crop marketing etc.
Fishing: The existence of river and canals indicate that the inhabitants
rely on fishing and marketing of fisheries for livelihood.
Forest resources: People probably use the forest resources such as
fruits, woods, fire woods, forest farming (rudimentary sedentary tillage),
forest business etc.
Transportation workers: People probably work in the transportation
industries as there is a huge shape of transport network in the area.
Religious institutions: There are a number of mosques, churches and
temple in the studied map. People may get engaged in serving religious
sectors in order to earn livelihood.
Industrial workers: There are few tea gardens in the supplied map.
Probable existence of cash crop industries may influence the inhabitants
to get engaged in laboring work.
4. Agricultural process: Agricultural process of the studied area is probably
primitive as it‟s situated in mostly rural areas. Fallow land, ancient instrument,
uneven land distribution etc. are the major characteristics of the agriculture of the
studied area. A plurality of the mapped location earns their living from
agriculture. Although rice and jute are the primary crops, wheat is assuming
greater importance. Tea is grown in the northeast. Because of Bangladesh's
fertile soil and normally ample water supply, rice can be grown and harvested
three times a year in many areas.
7.4: ANALYSIS BETWEEN THE PHYSICAL AND CULTURAL RELATIONS OF THE
SUPPLIED MAP The physical and cultural relations are quite vivid from the determined assumptions and physical
feature of the studied map. Those are written below-
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i. The studied map area is almost flat; consequently it was possible to establish
such large network in the studied map.
ii. There availability of transport and rivers persuaded the settlement patterns to be
nuclear and linear in the appropriate locations.
iii. The balancing between roads and railroads were possible because of the flat
terrain and unavailability of mountain areas.
iv. Water transport was possible because of the presence of rivers and canals in the
mapped area.
v. The availability of agricultural area persuaded the inhabitants to earn livelihood
from farming and agriculture.
vi. The availability of fluvial area persuaded the inhabitants to earn livelihood from
fisheries.
vii. The availability of forest area persuaded the inhabitants to earn livelihood from
using and manufacturing forest resources.
viii. The availability of cash crops persuaded the inhabitants to earn livelihood from
cash crop industry.
ix. The flat area and dispersed settlement persuaded the inhabitants to establish
village centers and town centers.
x. The physical feature of the area influences the inhabitants to lead their life in
accordance with the terrain and climate.
7.5: PREDICTION AFTER 24 YEARS After 24 years, several phenomena can be changed. Some predictions are made on the base of
present condition and assumptions. Those are written below.
i. Prediction about terrain: Several more depression area can be created because of
the mature stage of the river and its continuous changing shape. But the elevation
points should be stable as there is no major fault line in the studied map.
ii. Prediction about hydrology: The river may invade the surface because of the
river bank erosion. The changing feature of the river may influence the banks to be
eroded and deposited inside of the river.
iii. Prediction about vegetation coverage: The vegetation coverage may decrease as
there are a trend of inhabitants to increase the settlement; and also because of
population explosion and urbanization.
iv. Prediction about floodplain: Like any other fluvial area, the floodplain area is
tending to increase and get shaped and may create oxbow lake as well.
v. Prediction about transportation: The number of road and railroads may increase
in the future because of the border transit and international transportations. But it is
unlikely to get decreases the road network considering the demand and necessities.
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vi. Prediction about occupation: People may move to secondary economic activity
rather than primary with the advancement of technology, economy and
industrialization in the both country (India and Bangladesh).
vii. Prediction about agriculture: The advancement in agricultural sector is possible
and it is very likely. Introduction of modern technology, modern machinery,
modern methods of farming, and modern knowledge of farming will probably be
observed within the next 24 years in the study area.
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SECTION-2:
GEOLOGIC MAP
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8. GEOLOGIC MAP AND ITS TYPES A geologic map or geological map is a special-purpose map made to show geological features.
Rock units or geologic strata are shown by color or symbols to indicate where they are exposed
at the surface. Bedding planes and structural features such as faults, folds, foliations, and
lineations are shown with strike and dip or trend and plunge symbols which give these features'
three-dimensional orientations.
Geological maps fall into four main groups. These are: reconnaissance maps; maps made of
regional geology; large-scale maps of limited areas; and maps made for special purposes. Small-
scale maps covering very large regions are usually compiled from information selected from one
or more of these groups.
1. Geological reconnaissance maps: Reconnaissance maps are made to find out as much as
possible about the geology of an area as quickly as possible. They are usually made at a
scale of 1:250 000 or smaller, sometimes very much smaller. Some reconnaissance maps
are made by photogeology, which is by interpreting geology from aerial photographs,
with only a minimum of work done on the ground to identify rock types and to identify
dubious structural features, such as lineaments. Reconnaissance maps have even been
made by plotting the main geological features from a light aircraft or helicopter with,
again; only brief confirmatory visits to the ground itself. Airborne methods are
particularly useful in regions where field seasons are short, such as in northern Canada
and Alaska.
2. Regional geological maps: Reconnaissance may have given the outline of rock
distribution and general structure; now the geology must be studied in more detail, most
commonly at a scale of 1:50 000 or 1:25 000, although any resulting map will probably
be published at 1:100 000.
Regional geological maps should be plotted on a reliable base. Unfortu-nately, in some
countries, geological mapping outstrips topographic coverage when there is a sudden
economic interest in a specific area and geologists must then survey the topography
themselves. An accurate geological map loses much of its point if superimposed on an
inadequate topographic base.
Regional geological mapping done on the ground may be supported by systematic
photogeology, and it should be emphasised that photogeological evidence is not inferior
to information obtained on the ground although it may differ in character. Some
geological features seen on aerial photographs cannot even be detected on the ground
while others can even be more conve-niently followed on photographs than in surface
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exposures (see Section 4.10). All geological mapping should incorporate any techniques
which can help in plotting the geology and which the budget will allow, including
geophysics, pitting, augering, drilling and even the use of satellite images where
available.
3. Detailed geological maps: Scales for detailed geological maps may be anything from
1:10 000 and larger. Such maps are made to investigate specific problems which have
arisen during smaller-scale mapping, or from discoveries made during mineral
exploration, or perhaps for the preliminary investigation of a dam site or for other engi-
neering projects. In Britain 1:10 000 is now the scale used for regional maps by the
Geological Survey to cover the whole country, replacing the older „6 inches to the mile‟
series (1:10 560). Few countries match this detail for their regional topographic and
geological map coverage. This is also the scale most commonly used by British students
for their own mapping projects.
4. Specialised maps: Specialised maps are many and various. They include large-scale
maps of small areas made to record specific geological features in great detail. Some are
for research, others for economic purposes, such as open pit mine plans at scales from
1:1000 to 1:2500; underground geological mine plans at 1:500 or larger; and engineering
site investigations at similar scales. There are many other types of map with geological
affiliations too. They include geophysical and geochemical maps; foliation and joint
maps; and sampling plans. Most are superimposed over an outline of the geology, or
drawn on transparencies to be superimposed on geological maps, to study their
relationship with the solid geology.
9. IMPORTANCE OF GEOLOGIC MAP: An accurate geologic map is needed to understand the Earth‟s resources and hazards. A geologic
map provides basic data for understanding both past and present-day processes affecting a region
of the Earth. This kind of information is important for four main reasons:
1. To provide geologic information that can help to reduce death and damage caused
by geologic hazards such as earthquakes and landslides. Different types of geologic
materials can amplify shaking or even liquefy during earthquakes. Some also are more
likely to produce landslides, or they may contain natural deposits of hazardous asbestos
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or mercury. A geologic map shows where these types of geologic materials are, as well as
the location of faults that might generate earthquakes.
2. To better find and protect or safely extract geologic resources. Concrete, sand,
metals, petroleum, even groundwater, are all important geologic resources, but to benefit
society, they first must be found. A geologic map shows the distribution of the rocks and
sediments that are most likely to contain these resources.
3. To improve our stewardship of the Earth through informed agriculture,
construction, and environmental practices. A geologic map shows the distribution of
the types of geologic materials that are likely to produce poor soils that are unsuitable for
agriculture (for example, map unit Jsp). It also shows which rocks will provide the safest
foundations for buildings and roads, as well as those which can help support important or
endangered species.
4. To help geologists unravel the geologic history of the region. The relations between
the geologic materials and structures shown on the geologic map give clues about the
sequence of events that happened in the area in the past. An improved understanding of
the geologic history helps us to better understand the region's geologic resources and
hazards.
10. USES OF GEOLOGIC MAPS: Geologic map can be applied to assist the following phenomena-
Rock Descriptions
Identifying and Naming Rocks in the Field
Litho-stratigraphy and Sedimentary Rocks
Fossils Determination
Phaneritic Igneous Rocks Determination
Aphanitic Igneous Rocks Determination
Veins and Pegmatites Determination
Igneous Rocks Determination in General
Pyroclastic Rocks Determination
Metamorphic Rocks Determination
Interpretation of Economic Geology Aspects
Distribution of Geological Features
Land Planning
Construction Activities etc.
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Map 1: Geologic map of Bangladesh
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11. STAGES TO FORM A GEOLOGIC MAP: The main equipment needed to do geological mapping is:
1. Base Map: is used to show an overview of the area that will be mapped.
2. Compass and Clinometer: is used to measure the strike and dip from a rocks and
geological structure.
3. Stationery and field notebook: is used to record and describe the characteristic of
rocks was found at the observation location.
4. Hammers and Chisels: is used to take rocks samples.
5. Hand lens: is used to observe the characteristics of rock that cannot be seen with the
eye directly, such as the grain size and others
6. Gauge: is used is used to determine the length of an outcrop or structure.
7. GPS: is used to determine the outcrop location.
The steps to do geological mapping activity are:
1. We make outcrop observation, and make a description of it.
2. We measure the position of rocks (strike and dip), geological structure elements, and
other geological elements.
3. We make a record observations in a field notebook
4. We determine the outcrop location by using GPS.
STEPS TO CREATE GEOLOGICAL MAPS:
1. Make Geological Maps Framework
Geological maps framework is a set of data that is used to the process of makinga map. The
contents is:, symbols of station number (track); types of rock symbol; Plotting symbol of
strike/dip; Plotting symbol of structure element.
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Figure 8: Lithology of Outcrop and Field Structure Sketch.
2. Make a Strike and Dip Map
This map shows the plots of strike and dipfrom a region. In the reconstruction, it necessary some
step:
Inventory a required data, such as strike and dip, and the description ofrockintorock
unitsalong withits contacts as well asan indication ofthe geologicalstructures(faults,
folding)
Plotting data on the map. We make a contour map based on the similarity towards the
strike and dips of outcrops were obtained.
Figure 9: Strike/Dip Data Plot and Indication of Geology Structure.
How to reconstruct the pattern of strike of the rock layering pattern is as follows: plot the
data needed; create key strike/dip contour; reconstructs the geological structure if any;
and reconstructs the pattern of strike and dip.
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Figure 10: Data Plot on 25°
3. Make Geological Map
Some things that need to be considered in making geological maps is: determining the spread of
the unit and formation. restrict the lithology in accordance with the lithology contacts on the
strike and dip map. Also draw the location of geological structures in accordance with the
boundary of the strike and dip map. Give lithology colour in accordance with the standards
colour and provide explanation too. And the last, make the cross section from its map.
Cross Section
Geological maps can not be considered complete until there is at least one cross section has been
created to show the geology below the surface. Cross section describes the structure of a region
that is much clearer than a planimetris map.cross section can be drawn in addition to a map of
the fair copy,and simplified again as an illustration in a cross section of the report.it can show
geological formation boundary at depth,and can also be used to display a fault, cleavage and
surface folds on the map.
Measures to make a Cross section:
1. Draw the line section (A-B) on face of the map.
2. Fasten the map to the drawing board or table with the line Section in parallel on the lower
edges of the drawing board or table,
3. Tape part map, a few centimeters below the line section, then the line of paper to do the
plot lines of the section.
4. Basic line drawings on paper are parallel to the lines of the section of the map. Then pull
a series of parallel lines on a contour intervals selected Above. The distance of these lines
should be aligned with the vertical scale contour maps.
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5. Press the plastic ruler or a straight steel edge on paper until it cannot move, so that the
paper remains parallel to the base line.
6. By shifting the point of elevation along the edges, and drop a perpendicular down to the
appropriate height on the paper section of every point where this part is cutting the
contour lines on a map. Follow these points to give a profile of topography.
Figure 11: How to Make Cross Section
12. DEFINITION OF IMPORTANT GEOLOGIC TERMS: Bearing: Bearing refers to direction, especially angular direction measured from one
position to another using geographical or celestial reference lines.
Unconformity: An unconformity is a buried erosional or non-depositional surface
separating two rock masses or strata of different ages, indicating that sediment
deposition was not continuous. In general, the older layer was exposed to erosion for
an interval of time before deposition of the someonenger, but the term is used to
describe any break in the sedimentary geologic record.
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Figure 12: Hutton Unconformity
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Faulting: A faulting or fault is a planar
fracture or discontinuity in a volume of rock,
across which there has been significant
displacement as a result of rock-mass
movement. Large faults within the Earth's
crust result from the action of plate tectonic
forces, with the largest forming the
boundaries between the plates, such as
subduction zones or transform faults. Energy
release associated with rapid movement on
active faults is the cause of most earthquakes.
Strike: Strike is associated with dip. Dip
is the acute angle that a rock surface
makes with a horizontal plane. Strike is
the direction of the line formed by the
intersection of a rock surface with a
horizontal plane. Strike and dip are
always perpendicular to each other on a
map.
Line match: Line match refers to matching up, repairing, correcting and merging of
lines in a geologic map. A line is a straight one-dimensional figure in a geologic map
having no thickness and extending infinitely in both directions.
Figure 13: A Faulting in Morocco
Figure 14: Strike
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SECTION-3:
WEATHER MAP
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13. WEATHER MAP A weather map displays various meteorological features across a particular area at a particular
point in time and has various symbols which all have specific meanings. Such maps have been in
use since the mid-19th century and are used for research and weather forecasting purposes. Maps
using isotherms show temperature gradients, which can help locate weather fronts. Isotach maps,
analyzing lines of equal wind speed, on a constant pressure surface of 300 or 250 hPa show
where the jet stream is located. Use of constant pressure charts at the 700 and 500 hPa level can
indicate tropical cyclone motion. Two-dimensional streamlines based on wind speeds at various
levels show areas of convergence and divergence in the wind field, which are helpful in
determining the location of features within the wind pattern. A popular type of surface weather
map is the surface weather analysis, which plots isobars to depict areas of high pressure and low
pressure. Cloud codes are translated into symbols and plotted on these maps along with other
meteorological data that are included in synoptic reports sent by professionally trained observers.
Map 2: Current Weather map of Bangladesh
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14. SIGN AND SYMBOL OF A WEATHER MAP: There are several signs and symbols of a weather map. They have been discussed below.
TIME SYMBOL:
Figure 15: Time symbol
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HIGH AND LOW AIR PRESSURE CENTERS
Figure 16: High and Low Pressure Centre
Blue H's and red L's on weather maps indicate high and low pressure centers. They mark where
the air pressure is highest and lowest relative to the surrounding air and are often labeled with a
three- or four-digit pressure reading.
Highs tend to bring clearing and stable weather, whereas lows encourage clouds and
precipitation; so pressure centers are sort of "x-marks-the-spot" areas for determining where
these two general conditions will occur.
Pressure centers are always marked on surface weather maps. They can also appear on upper air
maps
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ISOBARS
Figure 17: Isobar
On some weather maps somone may notice lines surrounding and encircling the "highs" and
"lows." These lines are called isobars because they connect areas where the air pressure is the
same ("iso-" meaning equal and "-bar" meaning pressure). The more closely the isobars are
spaced together, the stronger the pressure change (pressure gradient) is over a distance. On the
other hand, widely-spaced isobars indicate a more gradual change in pressure.
Isobars are found only on surface weather maps -- although not every surface map. Be careful
not to mistake isobars for the many other lines that can appear on weather maps, like isotherms
(lines of equal temperature)!
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WEATHER FRONTS AND FEATURES
Figure 18: Weather Fronts and Features
Weather fronts appear as different colored lines that extend outward from the pressure center.
They mark the boundary where two opposite air masses meet.
Warm fronts are red curved lines with red semi-circles.
Cold fronts are blue curved lines with blue triangles.
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Stationary fronts have alternating sections of red curves with semi-circles and blue
curves with triangles.
Occluded fronts are purple curved lines with both semicircles and triangles.
Weather fronts are found ONLY on surface weather maps.
SURFACE WEATHER STATION PLOTS
Figure 19: Weather Station Plot
As seen here, some surface weather maps include groupings of numbers and symbols known as
weather station plots. Station plots describe the weather at a station location, including reports of
that location's...
air temperature (degrees Fahrenheit),
dewpoint temperature (degrees Fahrenheit),
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current weather,
sky cover,
atmospheric pressure (in millibars),
pressure tendency, and
wind direction and speed (in knots).
If a weather map has already been analyzed, someone'll find little use for the station plot data.
But if someone'll be analyzing a weather map by hand, station plot data is often the only
information someone start off with. Having all stations plotted on a map guides someone as to
where high and low pressure systems, fronts, and the like are located which ultimately helps
someone decide where to draw them in.
WEATHER MAP SYMBOLS FOR CURRENT WEATHER
Figure 20: Weather Map Symbols for Current Weather
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These symbols are used in weather station plots. They tell what weather conditions are currently
happening at that particular station location.
It is only plotted if some type of precipitation is occurring or some weather event is causing
reduced visibility at the time of observation.
SKY COVER SYMBOLS
Figure 21: Sky Cover Symbols
Sky cover symbols are used in station weather plots. The amount that the circle is filled
represents the amount of sky that's covered with clouds.
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The terminology used to describe cloud coverage -- few, scattered, broken, overcast -- are also
used in weather forecasts.
WEATHER MAP SYMBOLS FOR CLOUDS
Figure 22: Weather Map Symbols for Clouds
Each cloud symbol is labeled with an H, M, or L for the level (high, middle, or low) where it
lives in the atmosphere. The numbers 1-9 tell the priority of the cloud reported; since there's only
room to plot one cloud per level, if more than one cloud type is seen, only the cloud with the
highest number priority (9 being highest) is plotted.
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WIND DIRECTION AND WIND SPEED SYMBOLS
Figure 23: Wind Direction and Wind Speed Symbols
Wind direction is indicated by the line that extends out from the station plot sky cover circle.
The direction the line points is the direction that the wind is blowing from.
Wind speed is indicated by the shorter lines, called "barbs," which extend from this longer line.
The total wind speed is determined by adding together the different sizes of barbs according to
the following winds speeds that each represents:
Half barb = 5 knots
Long barb = 10 knots
Pennant (flag) = 50 knots
Wind speed is measured in knots and is always rounded to the nearest 5 knots.
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PRECIPITATION AREAS AND SYMBOLS
Figure 24: Precipitation Areas and Symbols
Some surface maps include a radar image overlay (called radar composite) that depicts
where precipitation is falling based on returns from weather radar. The intensity of rain, snow,
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sleet, or hail is estimated based on color, where light blue represents light rain (or snow) and
red/magenta indicates flooding rains and/or severe storms.
WEATHER WATCH BOX COLORS
If precipitation is severe, watch boxes will also show up in addition to precipitation intensity.
Red dashed = tornado watch
Red solid = tornado warning
Yellow dashed = severe thunderstorm watch
Yellow solid = severe thunderstorm warning
Green = flash flood warning
15. DIFFERENCE BETWEEN WEATHER AND CLIMATE: Weather is the day-to-day state of the atmosphere in a region and its short-term (minutes to
weeks) variations, whereas climate is defined as statistical weather information that describes the
variation of weather at a given place for a specified interval. They are both used interchangeably
sometimes but differ in terms of the length of time they measure and what trends affect them.
Weather is the combination of temperature, humidity, precipitation, cloudiness, visibility, and
wind. In popular usage, climate represents the synthesis of weather; more formally, it is the
weather of a locality averaged over some period (usually 30 years), plus statistics of weather
extremes.
Although they have similarities, but the both phenomena are different from each other in many
ways. The keys differences between weather and climate are shown below.
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Topic Weather Climate
Definition Weather is the state of the
atmosphere on a current day at a
current time. It changes day to day.
Climate is the average
conditions that are expected
at a certain place over a
number of years.
Components Weather includes sunshine, rain,
cloud cover, winds, hail, snow,
sleet, freezing rain, flooding,
blizzards, ice storms,
thunderstorms, steady rains from a
cold front or warm front, excessive
heat, heat waves and more.
Climate may include
precipitation, temperature,
humidity, sunshine, and
wind velocity, phenomena
such as fog, frost, and hail
storms over a long period
of time.
Forecast Day to day forecast can be done
depending on the air pressure,
temperature and other similar
factors.
Climate forecast can only
be done over longer periods
of time, such as 30 years.
The average of weather
over 30 years helps
determine the climate of a
certain area.
Determined by Real-time measurements of
atmospheric pressure, temperature,
wind speed and direction,
humidity, precipitation, could
cover, etc.
Aggregating weather
statistics over periods of 30
years
Study Meteorology Climatology
Table-1: Difference between Weather and Climate
16. CONCLUSION: The topographic, geologic and weather map all are essential for comprehending map study and
cartography. The understanding of weather symbol is essential for explaining weather map.
Altogether, it‟s essential to study each of them elaborately and vividly.