OFFICIAL LABWORK REPORT OF

Earth Science

Arranged by :

Aprilia Mantayani (14312241028 )

CLASS I SCIENCE EDUCATION 2014

STUDY PROGRAM OF INTERNATIONAL SCIENCE EDUCATION

MATHEMATICS AND NATURAL SCIENCE FACULTY

YOGYAKARTA STATE UNIVERSITY

2015

Contour Map

A. TITLE

Contour Map

B. OBJECTIVE

1. To develop the concept of representation of the earth, a small part of the earth

on paper.

2. To know the concept of scale as a miniature representation.

C. THEORY

A topographic map is a type of map that shows elevation. Topographic maps

are used by people like hikers and others who need to know what the elevation of

an area is. So what do these lines mean? Why are there so many, and why are they

so crooked? This lesson will be looking at just that: we will cover what a

topographic map is, what those lines are, and how they work. Specifically, we will

delve into the rules that those lines follow and how to make sense of the numbers

associated with them. Later on in the lesson, we'll learn how this information

connects to a true geologic map and how to read all those colors.

Topographic Map Basics

We begin our focus on the basic part of a topographic map, all those lines.

These are known as contour lines. Contour lines connect points of equal elevation.

All that means is that where there's a line, everything on that line is the same

height or altitude. Think of it this way, if you had a tub of water with a big rock in

it and you started filling the tub with water but paused every minute to draw a line

where the water had risen to - those lines would be like contour lines. If you did

this for the entire rock, then drained all the water out, the rock would have lines all

over it. If you looked at this from above, just like the whipped cream from before,

you would see all those lines connecting and forming circles. A topographic map

shows those lines. On most maps like this, these lines are shown with a light

brown color. If you were to look at a topographic map, you would realize that

there's not just one line, but many. Each line is a different elevation, but some of

the lines have numbers on them. These are called index contours. Index contours

display the exact elevation of one specific line. Why not just put numbers on

every line? Space. There just isn't enough room on the map to keep putting

numbers everywhere, and it would get awfully cluttered if we did. We'll touch on

this idea again later on. To put this into perspective, imagine you are somewhere

with a big staircase. Maybe you're at the Pyramids of Giza or one of those big

concrete sports arenas or any other place where there's lots of steps. Imagine you

are at the very bottom of those steps. If you start hiking up the stairs, the tenth step

up would be painted light brown. Not just in one spot, the entire step, all the way

across. It would represent 10 feet high. This would be one of your contour lines.

If you went up another 10 steps there would be another step painted brown there

as well. If you keep going, eventually you will probably lose count of how many

steps you took. Don't believe me? Go run stairs somewhere and try to remember

what floor you are on, try a tall hotel stairwell. After a while you'll get tired and

start to forget. Well lucky for you, after your 50 stairs, you see a painted step that

has a big 5-0 printed on it. Do Why don't you have a seat, catch your breath and

take look around. This step with a big 50 painted on it means that you're now 50

feet above sea level. Each index contour might only be labeled in two or three

other places - it keeps the clutter down (Muhammad:2005).

Contour Ruler

One different thing about topographic maps: they have rules. Specifically the

contour lines have rules - and every topographic map follows them:

1. Lines cannot cross.

2. Lines form circles around hills or depressions.

While that would be pretty cool, being at two different elevations at the same

time would cause some serious issues with physicists because basically you would

need to be in two different places at one time, and that can't happen.

While we're focused on lines here, look at the space between any two

lines. This is called the contour interval. Contour interval is the distance

between any two side-by-side lines. For example, a contour interval of 10

means you would change elevation 10 feet up or down by crossing over those

lines on the map. It depends which way you're traveling. Every space

between every line on that map would be 10 feet of elevation change, no

matter how close or spread out those lines are. This information will either be

printed on the map somewhere or you can figure it out by looking at the

index contours. Now, lines can (and often do) get really close to each other.

The closer those lines, the steeper the hill would be. A sheer cliff would have

lines all piled up to show that drastic elevation change, and a gentle slope

would have contour lines much more spread out. See how these lines are all

bunched up here? This is a topographic map that would represent this type

of cliff landform.

The other rule we need to look at states: contour lines close around

hills and depressions. This is probably best explained by going back to our

step idea. If you were to run all the way around the base of one of the

pyramids, it would make one big square. If you were to then go up 10 feet to

that first painted level of painted step and run around that that, it would make

another square. This would be a little bit smaller, but the same exact shape. If

you kept doing that, eventually you would you would probably be arrested, but

you would up with a bunch of concentric squares. Eventually it would look

like a square bull's eye with the center being the smallest square. The same is

true for hills and mountains. As you go up in elevation, that circle will get

smaller and smaller. Just like lines in the whipped cream, the lines here would

completely surround the pyramid (Gross:2006)

Up until now we've only talked about contour lines going up in elevation.

D. METHODS

1. Time and location

Location : Laboratorium IPA 2

Date : Thursday , 8th Oktober 2015

Time : 09.20-11.00 WIB

2. Tools and materials

a. clay,

b. a piece of paper,

c. a pencil,

d. skewers,

e. books

f. ruler

E. OBSERVATION PROCEDURE

Shaping clay or plasticine into a miniature mountain, complete with hills and valleys, slopes with a gradual slope at the top of the cardboard.

Put a thick book on a table next to a miniature mountain

Eyes fixed position above the book and then look at the mountain. mark around the highest part of the mountain that part of the book.

Draw a line around the mountain with toothpicks / skewers to connect the sign that was created in step 3.

Observe the lines that have been drawn on tapat mountain from the top of the mountain (perpendicular). whether the line is a circle? The line represents what?

Perform steps 2-4 by using a thinner book and 7. do steps 2-4 using thick and thin books stacked.

Sketch on paper mountain appearance when viewed from above berdasarkab lines already drawn on the mountain

Observe the lines that have been drawn on the right of the mountain from the top of the mountain (perpendicular). apakalh the line apart at the same distance on the

surrounding mountains? section where the lines berdekatab running?

F. OBSERVATION RESULTS

Observation result of the miniatur

With use skala 1:20.000 and with long 47,5 cm to large 28,5 cm.

G. DISCUSSIONS

Percobaan yang berjudul Peta Kontur yang dilakukan pada hari kamis, 8

Oktober 2015 bertujuan untuk mengembangakan konsep respresentasi bumi,

bagian kecil bumi dari bumi pada kertas dan mengetahui konsep skala sebagai

representasi bentuk miniatur. Adapun alat dan bahan yang digunakan adalah tanah

lempung, selemabar kertas, pensil, tusuk gigi, buku-buku, pengaris, dan jarum

pentul. Adapun langkah-langkah yang harus dikerjakan dalam praktikum ini

adalah sebagai berikut menyediakan peta topografi yang akan diinterpretasikan,

selanjutnya menentukan titik ketinggian, kemudian menghubungkan titik ke

tinggian yang sama dengan menarik garis lurus yang tidak putus dan tidak saling

berpotongan, membuat profil peta topografi dari garis kontur yang diperoleh dan

terakhir membuat sketsa penampakan gunung pada kertas. Pada percobaan ini

untuk sketsa penampakan gunung dengan ukuran panjang 47,5 cm dan lebar 28,5.

Garis kontur adalah garis khayal dilapangan yang menghubungkan titik

dengan ketinggian yang sama atau garis kontur adalah garis kontinyu diatas peta

yang memperlihatkan titik-titik diatas peta dengan ketinggian yang sama. Nama

lain garis kontur adalah garis tranches, garis tinggi dan garis tinggi horizontal.

Garis kontur + 25 m, artinya garis kontur ini menghubungkan titik-titik yang

mempunyai ketinggian sama + 25 m terhadap tinggi tertentu. Garis kontur

disajikan di atas peta untuk memperlihatkan naik turunnya keadaan permukaan

tanah. Aplikasi lebih lanjut dari garis kontur adalah untuk memberikan informasi

slope (kemiringan tanah rata-rata), irisan profil memanjang atau melintang

permukaan tanah terhadap jalur proyek (bangunan) dan perhitungan galian serta

timbunan (cut and fill) permukaan tanah asli terhadap ketinggian vertikal garis

atau bangunan.

Garis kontur dapat dibentuk dengan membuat proyeksi tegak garis-garis

perpotongan bidang mendatar dengan permukaan bumi ke bidang mendatar peta.

Karena peta umumnya dibuat dengan skala tertentu, maka untuk garis kontur ini

juga akan mengalami pengecilan sesuai skala peta. Garis-garis kontur merupakan

cara yang banyak dilakukan untuk melukiskan bentuk permukaan tanah dan

ketinggian pada peta, karena memberikan ketelitian yang lebih baik. Cara lain

untuk melukiskan bentuk permukaan tanah yaitu dengan cara hachures dan

shading.

Berdasarkan hasil praktikum mengenai peta kontur, dapat menginterpretasi

suatu daerah berdasarkan sketsa penampakan gunung dengan tanah lempung. Pada

praktikum ini dengan mengambarkan sketsa gunung dapat menunjukan kondisi

suatu daerah yaitu dengan adanya lembah, daratan yang tinggi maupun tegak,

misalnya dari kerapatan garis kontur kita dapat mengetahui kondisi bentang alam

suatu daaerah, dari pola aliran sungai yang nampak pada peta. Dapat juga dari

interpretasi suatu sketsa gunung kita juga dapat menghitung beda tinggi yang

berguna untuk mengetahui berapa beda antara tempat tertinggi dengan tempat

terendah suatu daerah. Mengukur jarak datar yang berguna untuk mengetahui

jarak kelandaian suatu daerah, mengetahui persen suatu kemiringan lereng yang

berguna untuk menentukan tingkat kemiringan.

Dari hasil percobaan tersebut untuk Interval kontur yang merupakan jarak

vertikal antar garis yang satu dengan garis kontur yang lainnya secara berurutan.

Pada percobaan ini skala 1: 20.000 dicantumkan interval konturnya 2 cm.

Pada sketsa gambar peta kontur berskala 1:40.000 mempunyai ukuran

23,7 x 14,25 cm dan diberi nomor dengan angka ke arah horizontal, dengan makin

besar arah vertikal menggunakan angka Romawi dengan makin kebawah makin

besar. Seperti gunung merupakan rangkaian garis kontur berbentuk huruf U

dimana U dari huruf U menunjukan tempat atau daerah yang lebih pendek dari

kontur diatasnya. Lembah atau Sungai Lembah atau sungai merupakan rangkaian

garis kontur yang berbentuk n (huruf V terbalik) jung dengan Ujung yang Tajam.

Daerah landai datar dan terjal curam Daerah datar/landai garis konturnya jarang,

sedangkan daerah terjal atau curam garis konturnya rapat.

Gambar peta kontur menurut literatur

Untuk dapat lebih mempermudah pembacaan garis kontur, maka dibuat

kembali model penggambaran dengan tampilan tiga dimensi. Dimana pada tampilan

tiga dimensi, beda ketinggian dari suatu daerah dengan garis kontur dapat terlihat

dengan lebih jelas dan mudah. Untuk membuat tampilan tiga dimensi tersebut maka

diperlukan data masukan berupa peta topografi yang dianalisa dan diproses kedalam

output model objek tiga dimensi.

H. CONCLUSION

Based on the results of experiments conducted can be concluded that:

1. Topography map is a map that shows the state of the earth of an area, usually

using contour lines in modern maps.

2. Topographic maps also illustrate as much as possible the characteristics of the

surface of a specific area within the limits of the scale.

I. DISCUSSION

1. What a contour map?

The map that you have been given contains elevation point. Based on these

oints you are to draw in the countur lines. Choose an appropriate contour

interval by examming the elevation ponts on your map. If your total relief( the

difference between the highest and lowest elevation) is large, you wikneed a

large contour interval. The most common intervals are 10 0r 20 ft for less

relief and 100 ft for greater relief. Refer to the following guidelines and 2

when drawing.

2. How to read a map contour?

Ruler for contour lines

a. A contour line must never divide or sprit

b. A contour line ush never simply end. Somewhere (usully off the map) the two ends of a contour line must join to endclsoe an irregulary circular region.

c. A contour line must represent one and only one elevation

d. A contour line may never intersect other lines (overhanding cliffs a rare excpetion, in which case the hidden contours are dashed).

e. Contour line from a V pattern when crossing streams. The V always points upstream (uphalll)

f. Closely spaced contour lines indlcate a steep slope; widely spaced lines inslacate a gentle slope.

g. Concentric circles of contour lines indlcate a hilltop or mountoin peak

h. Concentric circles of hachured contour lines indlcate hollow or closed depression.

3. what it means when the contour lines coincide?

contour lines indicate a steep slope coincide

REFERENCES

Gross, M.G.2006. A View of Earth. Prentice Hall, Inc. Englewood Cliff . New

Jersey.

Muhammad, hamid. 2005. Ilmu Pengetahuan Sosial-Geografi. Jakarta:

Departemen Pendidikan Nasional.

http://study.com/academy/lesson/how-to-read-topographic-and-geologic-

maps.html, diakses pada sabtu, 10 oktober 2015 pada pukul 19.00 WIB.

http://adventure.howstuffworks.com/outdoor-activities/hiking/how-to-read-a-

topographic-map5.htm. Diakses pada sabtu, 10 oktober 2015 19.10 WIB.

Lampiran